1 Introduction

Photosynthesis, as the core physiological process of plant material accumulation and energy conversion, directly determines the biomass formation and yield potential of crops through its efficiency in converting light energy into chemical energy. In the current global food security context, enhancing photosynthetic efficiency through multidimensional strategies has become an important direction in crop physiology research. Current research mainly focuses on: (1) genetic improvement pathways, including rate limiting enzyme expression optimization based on dynamic modeling (such as the synergistic regulation of Rubisco activating enzyme and SBPase in potatoes) (Vijayakumar et al., 2023), as well as the modification of photoresponsive pathways by transgenic technology, although the latter has genotype dependent expression differences (Lehretz et al., 2022); (2) The agronomic regulation system optimizes the efficiency of light interception and carbon assimilation allocation through cultivation measures. These studies provide a theoretical basis for analyzing the coupling mechanism between photosynthesis regulatory networks and crop yield formation.

Potato (Solanum tuberosum L.), as a globally important non cereal crop, has a significant synergistic effect on yield formation and stress resistance enhancement due to the improvement of its photosynthetic efficiency. Research has shown that genetic improvement can effectively promote carbon assimilation flux and tuber biomass accumulation. For example, heterologous expression of Arabidopsis thaliana light signal regulator AtBBX21 gene significantly increased net photosynthetic rate and tuber yield while maintaining water use efficiency (Crocco et al., 2018). In addition, comparative physiological analysis of multiple varieties confirms that under CO₂ enrichment conditions, some potato germplasm resources exhibit a dual improvement in photosynthetic performance and water use efficiency, thereby achieving yield gains (Theeuwen et al., 2022; Dahal et al., 2023; Manning et al., 2023; Tao and Han, 2024). These findings provide important physiological solutions for addressing food security challenges in the context of climate change.

The aim of this study is to systematically analyze the genetic regulation methods and agronomic optimization methods involved in the current strategies for improving the efficiency of potato photosynthesis, with a focus on exploring the regulatory mechanisms of genetic improvement techniques (including overexpression strategies for key genes in photosynthesis and optimization of enzyme activity of ribulose-1,5-diphosphocarboxylase/oxygenase Rubisco) on photosynthetic physiological processes. At the same time, the study examines the synergistic effects of agronomic management measures (such as light environment parameter regulation and CO₂ concentration gradient optimization) on photosynthetic performance indicators and yield formation. Based on the principles of plant physiological ecology, the mechanism analysis and solution demonstration of metabolic limiting factors (such as source sink imbalance and light adaptation mechanism obstacles) that may exist in the technical implementation process are conducted. By integrating the latest experimental evidence and theoretical models in the field of photosynthesis research, this review aims to construct a multidimensional technical framework for improving the photosynthetic efficiency of potatoes, providing theoretical basis and practical guidance for improving the theoretical system of high and stable yield and stress resistance improvement of this crop.

2 Photosynthesis in Potato: Basics and Challenges

2.1 Anatomy and physiology of potato photosynthesis

As an important non-gramineous food crop in the world, potato has a typical C3 plant photosynthesis system, including complex anatomical structures and physiological and biochemical regulatory networks. This process mainly occurs on the chloroplast thylakoid membrane, where chlorophyll molecules capture light quanta, drive the electron transport chain of photosystems II and I, and ultimately convert CO₂ and H₂O into carbohydrates and release O₂. In this process, Rubisco enzyme is the key rate-limiting factor of the Calvin cycle, and its carboxylation efficiency directly affects the fixation rate of CO₂ to 3-phosphoglycerate (Vijayakumar et al., 2023). Molecular genetic studies have shown that the expression level of the light signal regulator AtBBX21 is significantly positively correlated with the photosynthetic efficiency of potatoes. This gene not only increases the maximum photosynthetic rate (Pmax) by stabilizing the synthesis of the photosystem II reaction center protein D1, but also significantly reduces the light inhibition induced by high light intensity (Crocco et al., 2018). These findings provide new molecular targets for analyzing the gene regulatory network of potato photosynthesis.

2.2 Key factors limiting photosynthesis efficiency in potatoes

The regulation of potato photosynthesis efficiency is influenced by multiple levels of physiological limiting factors. At the gas exchange level, stomatal conductance directly affects the carbon supply to the chloroplast microenvironment by regulating the diffusion rate of CO₂/O₂; And the mesophyll conductance further restricts the transport efficiency of CO₂ to carboxylation sites. At the biochemical metabolic level, the carboxylation/oxygenation activity of Rubisco enzyme and the productivity efficiency of the thylakoid membrane electron transport chain jointly constitute the core limiting factors for photosynthetic carbon assimilation (Flexas et al., 2016). The genetic improvement strategy faces significant challenges: on the one hand, the high synergy of various components of photosynthesis (light harvesting complexes, Calvin cycle enzyme systems, stomatal regulatory networks, etc.) limits the effectiveness of single target modification; On the other hand, overexpression of key photoprotective genes (such as the non photochemical quenching related gene PsbS) can enhance light stress resistance, but under dynamic light conditions, it may lead to a decrease in net photosynthetic rate and tuber yield due to energy allocation imbalance (Figure 1) (Lehretz et al., 2022). These findings highlight the complexity of the potato photosynthetic regulatory network and the necessity for systematic improvement.

2.3 Environmental constraints and their impact on photosynthetic performance

The photosynthetic efficiency of potato is regulated by multiple environmental factors. In terms of light stress, high irradiance can trigger the degradation of D1 protein in the reaction center of photosystem II, leading to photoinhibition; while the expression of AtBBX21 gene significantly improves the efficiency of light energy utilization and reduces the risk of light damage by stabilizing the structure of photosynthetic membrane complex (Crocco et al., 2018; Ocampo et al., 2021). Water stress inhibits the activity of the electron transport chain and induces reactive oxygen burst by destroying the proton gradient of the thylakoid membrane, but the introduction of alternative electron transfer pathways mediated by flavoproteins can effectively maintain the efficiency of photosynthetic phosphorylation under water deficit conditions (Karlusich et al., 2020).

As a key substrate for chlorophyll synthesis and Rubisco enzyme assembly, nitrogen nutrition utilization efficiency (NUE) is significantly positively correlated with the photosynthetic carbon assimilation rate. Genome-wide association analysis combined with physiological phenotype screening confirmed that optimizing the coordinated expression of nitrogen transporters (such as NRT2.1) and assimilation enzymes (GS/GOGAT) can increase photosynthetic output per unit nitrogen input (Tiwari et al., 2018; Tiwijari et al., 2020). These findings provide a theoretical basis for constructing an "environmentally adaptive" photosynthetic regulatory network. By integrating molecular design breeding (such as the introduction of C4 metabolic modules) and precision agronomic management (coordinated regulation of water and fertilizer), it is expected to break through the current yield bottleneck.

3 Genetic Approaches to Enhance Photosynthesis Efficiency

3.1 Advances in genetic engineering for photosynthesis enhancement

In recent years, genetic engineering technology has shown significant potential in improving crop photosynthetic efficiency, and potatoes, as a typical C3 plant, are no exception. The research focuses on the molecular modification of Rubisco enzyme (ribulose-1,5-diphosphate carboxylase/oxygenase), aiming to improve its carboxylation efficiency and inhibit oxygenation activity. For example, by heterologous expression of Rubisco variants with high CO₂ affinity (such as RbcL2 derived from red algae), an increase in carboxylation rate has been achieved in tobacco and rice, but no significant biomass advantage has been shown under standard growth conditions (Iñiguez et al., 2021). In addition, introducing the carbon concentration mechanisms (CCMs) of blue-green and green algae, such as carboxylase structures, into higher plants has shown the potential to enhance carbon assimilation efficiency by increasing the CO₂ concentration at Rubisco binding sites (Nowicka et al., 2018). These studies provide new technological pathways for breaking through the evolutionary limitations of C3 plant photosynthetic efficiency.

3.2 Case Study: CRISPR-based modifications for rubisco efficiency in potatoes

The CRISPR-Cas9 gene editing technology provides precise molecular manipulation for optimizing the function of potato Rubisco enzyme. The study successfully regulated the catalytic kinetic parameters of Rubisco by targeting the coding genes of its large subunit (rbcL) and small subunit (rbcS), including improving carboxylation efficiency and reducing oxygenase activity. It is worth noting that when combined with the synergistic expression regulation of key enzymes in the Calvin cycle, such as FBP aldolase and SBPase, this strategy increased the net photosynthetic rate of potatoes by 28% (Vijayakumar et al., 2023). This achievement not only confirms the effectiveness of multi gene collaborative editing in photosynthesis improvement, but also provides a new technological paradigm for molecular design breeding to increase crop yield.

3.3 Integration of photosynthetic pathway genes from C4 and CAM plants

The introduction of key genes of C4 and CAM photosynthetic pathways into C3 crop potatoes is an important direction of current photosynthesis improvement research. The CO₂ concentration mechanism unique to C4 plants (such as corn) significantly improves photosynthetic efficiency by reducing photorespiratory losses. Although there are challenges such as tissue differentiation and metabolic coordination in transferring the complete C4 metabolic pathway into C3 plants, the selective introduction of Rubisco into NADP-ME type C4 plants has shown the potential to improve the carbon assimilation efficiency of C3 plants in simulation experiments, especially in the high CO₂ environment under the background of future climate change (Sharwood et al., 2016). Also worthy of attention are the gene resources of the CAM pathway, whose characteristics of fixing CO₂ at night can significantly improve photosynthetic productivity under water stress conditions. Studies have shown that by introducing genes encoding key enzymes of CAM plants (such as PEP carboxylase), potatoes can maintain carbon assimilation while keeping daytime stomata closed, thereby significantly improving water use efficiency (Éva et al., 2019). These cross-photosynthetic gene transfer strategies provide new ideas for breaking through the evolutionary limitations of photosynthetic efficiency of C3 crops.

3.4 Role of molecular markers and QTL mapping in breeding programs

Molecular markers and quantitative trait loci (QTL) mapping technology have important application value in modern potato photosynthetic efficiency improvement breeding. These molecular genetic tools can accurately analyze genetic variations related to key physiological parameters of photosynthesis, providing a theoretical basis for screening excellent genotypes. Research has shown that QTL mapping can effectively identify chromosomal segments that regulate core traits such as Rubisco enzyme activity, stomatal conductance, and electron transfer efficiency. "- Flexas et al., 2016. Integrating the above molecular markers into the marker assisted selection (MAS) breeding system can significantly improve selection efficiency and accelerate the cultivation of new potato varieties with high photosynthetic performance and yield potential. This strategy provides a molecular level solution to overcome the bottleneck of traditional breeding.

3.5 Genetic diversity in potato germplasm for photosynthesis traits

The analysis of genetic diversity of photosynthetic related traits in potato germplasm resources is an important foundation for improving photosynthetic efficiency. Research has shown that there is significant natural variation in the temperature response characteristics and catalytic efficiency of Rubisco enzyme among different genotypes of potatoes (Galmés et al., 2019). This variation provides a genetic basis for screening materials with excellent photosynthetic characteristics through traditional hybrid breeding. Meanwhile, in-depth analysis of the genetic mechanisms of these traits can guide the development of precision breeding strategies and provide molecular targets for targeted gene editing (Hussain et al., 2021). At the technical application level, the gene editing system based on CRISPR-Cas9 and the cross species transfer of key genes in the C4/CAM pathway provide new ideas for breaking through the limitations of C3 plant photosynthetic efficiency. By combining molecular marker assisted selection (MAS) and QTL mapping techniques, efficient screening of complex traits related to photosynthesis can be achieved. These technological advancements, combined with abundant potato germplasm resources, have laid a theoretical and practical foundation for cultivating new varieties with high photosynthetic efficiency and environmental adaptability.

4 Agronomic Practices to Improve Photosynthetic Efficiency

4.1 Optimized nutrient management (e.g., nitrogen and phosphorus application)

The improvement of photosynthetic efficiency in potatoes is closely related to nutrient management strategies, among which nitrogen (N) and phosphorus (P) are key macronutrients, and their supply patterns directly affect chloroplast development and photosynthetic enzyme activity. Excessive nitrogen fertilizer application not only poses a risk of environmental pollution, but also causes resource waste, therefore improving nitrogen use efficiency (NUE) has become a research focus. Through multi omics joint analysis, multiple key gene loci regulating nitrogen assimilation (such as GS/GOGAT cycle) and transport (such as NRT gene family) have been identified, providing targets for molecular marker assisted breeding (Tiwari et al., 2018; Tiwari et al., 2020).

At the practical level of agronomy, the precise regulation strategy of combining slow-release nitrogen fertilizer with staged fertilization can significantly improve the nitrogen supply dynamics throughout the entire growth period of potatoes. Research has shown that phased nutrient supply based on crop fertilizer requirements can maintain the continuous synthesis of photosynthetic active substances in leaves, resulting in a 15% to 20% increase in net photosynthetic rate (Koch et al., 2019; Shrestha et al., 2023). This "genetic agronomic" collaborative optimization model provides theoretical basis and technical support for achieving a resource efficient potato production system.

4.2 Impact of irrigation strategies on photosynthetic capacity

Irrigation regulation strategy is a key agronomic measure to maintain the photosynthetic physiological activity of potatoes. The appropriate soil moisture condition directly regulates CO ₂ assimilation efficiency by affecting stomatal conductance and mesophyll conductance. Research has shown that root zone hypoxia caused by excessive irrigation can inhibit mitochondrial respiration and ATP synthesis, thereby reducing the rate of photosynthetic electron transfer; The use of deficit irrigation (reducing water by 10%~30% compared to full irrigation) can induce crops to produce osmoregulatory substances, significantly improving water use efficiency while maintaining net photosynthetic rate (Shrestha et al., 2023). A more precise water fertilizer collaborative management technology - drip irrigation fertilization system, achieves spatiotemporal matching between crop demand and resource supply by synchronously supplying water and mineral nutrients (such as nitrogen). This technology not only increases the nitrogen content of leaves (directly affecting Rubisco enzyme activity), but also optimizes the source sink allocation of photosynthetic products, resulting in synchronous improvement of yield and water productivity (Li et al., 2021). This precise irrigation mode based on crop physiological needs provides a reliable solution for high-yield and efficient cultivation of potatoes in arid areas.

4.3 Use of intercropping and canopy management for light optimization

Intercropping system and canopy regulation technology are important agronomic measures to improve the light energy utilization efficiency of potatoes. Studies have shown that the intercropping pattern of potatoes and leguminous crops (such as Canavalia ensiformis and Phaseolus lunatus) significantly improves the photosynthetically active radiation utilization efficiency (RUE) and crop water productivity (CWP) by increasing the leaf area index (LAI) and light interception rate of the composite population (Figure 2) (Gitari et al., 2018; Nyawade et al., 2019). This planting system also improves the field microclimate environment and maintains soil temperature and humidity conditions that are conducive to photosynthetic carbon assimilation. In terms of canopy structure optimization, directional pruning and plant shaping technology can adjust the leaf inclination distribution so that light energy is more evenly distributed inside the canopy. This regulation not only avoids the waste of light saturation of the upper leaves, but also alleviates the light limitation of the lower leaves, thereby improving the photosynthetic efficiency of the population as a whole. Relevant agronomic measures provide a practical basis for building an efficient photosynthetic production system.

4.4 Role of biostimulants and growth regulators in photosynthesis efficiency

Biological stimulants and plant growth regulators are novel regulatory methods for enhancing the photosynthetic efficiency of potatoes, exerting their effects through multiple physiological mechanisms. This type of active substance includes natural extracts (such as seaweed polysaccharides, amino acid complexes) and synthetic compounds. Its mechanism of action mainly includes: (1) promoting chloroplast development and increasing chlorophyll content per unit leaf area; (2) Enhance root morphology and expand nutrient absorption surface area; (3) Activate the antioxidant defense system to alleviate damage to photosystem II caused by environmental stress. Research has shown that treatment with seaweed extract can increase the maximum photochemical efficiency (Fv/Fm) of PSII in potato leaves by 12% to 15%, while promoting the transport of carbohydrates to tubers (Tiwari et al., 2020). In terms of plant hormone regulation, cytokinins (such as 6-BA) maintain photosynthetic activity by delaying leaf senescence, while gibberellins (GA3) enhance light harvesting ability by expanding leaf area. When combined with precision irrigation, optimized intercropping systems, and other agronomic measures, these bioactive substances can form a synergistic effect, increasing the population photosynthetic rate by 18% to 22%. This integrated strategy of "physiological regulation agronomic optimization" provides a new technological approach for achieving resource efficient potato production.

5 Case Study: Enhancing Photosynthesis Efficiency through Chloroplast Engineering

5.1 Overview of chloroplast-targeted modifications

Chloroplasts, as the core organelles for energy conversion in photosynthetic eukaryotic cells, directly affect the carbon assimilation ability of plants in terms of their efficiency in converting light energy into chemical energy. Modern genetic engineering technology has achieved precise modification of chloroplasts at multiple levels: (1) by introducing efficient Rubisco variants of purple non sulfur bacteria (Rhodospirillum rubrum), carbon fixation efficiency comparable to the wild type can be maintained under CO₂ enrichment conditions, while significantly improving carboxylation reaction rates (Manning et al., 2023); (2) The potato chloroplast proteome map constructed based on high-throughput mass spectrometry technology revealed key targets including electron transfer chain complex regulatory proteins and redox modification sites, providing a molecular basis for optimizing the photosynthetic metabolism network (Liu et al., 2022); (3) Nanocarrier technology, such as chloroplast targeted liposomes, has achieved efficient delivery of exogenous genes and co factors. By precisely regulating the assembly of thylakoid membrane proteins, the quantum yield of photosystem II has been increased by 18% (Santana et al., 2022). These breakthrough advances provide multi-scale regulatory strategies for the rational design of photosynthetic systems.

5.2 Application in enhancing light energy capture and carbon fixation

As a cutting-edge field in photosynthesis improvement, chloroplast engineering optimizes the efficiency of light energy capture and carbon fixation through multidimensional strategies. Research has shown that binding fluorescent molecules with aggregation induced emission (AIE) properties, such as TPE derivatives, specifically to thylakoid membranes can significantly broaden the range of light absorption spectra (400~700 nm) and increase the utilization efficiency of photosynthetically active radiation by 23% to 28% (Bai et al., 2020). At the level of carbon assimilation, by biomimetic construction of blue-green algae type carboxylase micro chamber structures, the concentration of CO₂ around Rubisco enzyme can be increased by 5~8 times, effectively inhibiting oxygenase activity and increasing net carbon fixation rate by more than 35% (Giessen and Silver, 2017). These engineering transformations have achieved full chain optimization from light energy absorption to carbon assimilation, providing a new paradigm for breaking through the evolutionary limitations of C3 plant photosynthetic efficiency.

5.3 Challenges and future perspectives of chloroplast engineering in potato

Although chloroplast engineering has made some progress in improving the photosynthetic efficiency of potatoes, it still faces several key scientific problems and technological bottlenecks: (1) Photosynthesis, as a complex metabolic network with multiple components working together, requires precise regulation of gene expression balance in key links such as photosystem complex assembly, electron transport chain reconstruction, and Calvin cycle optimization for engineering transformation. Single target modification is often difficult to achieve phenotypic breakthroughs (Vijayakumar et al., 2023); (2) The introduction of exogenous genes may disrupt the redox homeostasis of chloroplasts, induce reactive oxygen species bursts, and exacerbate photoinhibition, which requires the establishment of a more comprehensive physiological risk assessment system (Santana et al., 2022).

Future research directions should focus on: (1) developing spatiotemporal specific delivery systems based on nanocarriers and viral vectors to achieve efficient and precise editing of chloroplast genomes; (2) Systematically analyze the allelic variations of photosynthetic related traits in potato germplasm resources and identify key natural variation sites that regulate light energy utilization efficiency (Sakoda et al., 2022). By integrating synthetic biology and population genetics methods, chloroplast engineering is expected to break through existing technological limitations and provide innovative solutions for increasing potato yield potential.

6 Interdisciplinary Approaches

6.1 Role of systems biology and computational modeling in understanding photosynthesis pathways

Systems biology and computational modeling techniques provide an important research paradigm for analyzing and optimizing the photosynthetic metabolic network of potato. By integrating multi-omics data (transcriptome, proteome, metabolome), the rate-limiting steps and potential genetic regulation targets in the carbon assimilation pathway can be systematically identified. Mathematical model simulation based on enzyme kinetics shows that in theory, CO₂ assimilation can be increased by 67% by globally regulating the gene expression network, but experimental verification shows that selective optimization of the activity combination of core enzymes such as Rubisco, FBP aldolase and SBPase can achieve a net photosynthetic rate gain of 28% (Theeuwen et al., 2022; Vijayakumar et al., 2023). Such models provide a theoretical basis for optimizing the resource allocation of photosynthesis-related enzymes by quantifying the metabolic flux allocation efficiency, thereby guiding the formulation of precise gene editing strategies.

6.2 Integration of remote sensing technologies for real-time monitoring of photosynthetic traits

Remote sensing technology, as an important tool for studying photosynthetic phenotypes, provides multidimensional data support for evaluating potato photosynthetic efficiency through non-contact measurements. This technology can synchronously obtain chlorophyll fluorescence parameters (such as Fv/Fm, Φ PSII), canopy temperature, and hyperspectral reflectance, which are significantly correlated with physiological processes such as photosystem II quantum efficiency and non photochemical quenching. A high-throughput phenotype platform based on chlorophyll fluorescence imaging can achieve dynamic analysis of photosynthetic function from single leaf to population level, which is particularly suitable for studying the adaptive regulation mechanism of photosynthetic mechanisms under environmental fluctuations (Van Bezouw et al., 2019). By integrating remote sensing phenotype data with genome-wide association analysis (GWAS), QTL loci regulating photosynthetic efficiency can be accurately located, providing targets for molecular design breeding (Manning et al., 2023). This "phenotype genotype" collaborative analysis model significantly improves the genetic analysis efficiency of complex traits.

6.3 Potential of artificial intelligence in optimizing photosynthesis-related agronomic practices

Artificial intelligence technology has shown significant potential for paradigm innovation in the field of photosynthesis and agronomic optimization. Its core advantage lies in integrating heterogeneous data from multiple sources (genome, phenotype group, environmental parameters, etc.), constructing predictive models through deep learning algorithms, and achieving intelligent agricultural decision-making. Taking the optimization of nitrogen use efficiency (NUE) in potatoes as an example, phenotype image analysis based on convolutional neural networks (CNN) combined with genome-wide association analysis (GWAS) can accurately identify key gene loci regulating nitrogen assimilation and transport (such as GS2, NRT2.1), providing molecular targets for variable fertilization strategies (Figure 3) (Tiwari et al., 2020).

More importantly, the artificial intelligence system can dynamically adjust irrigation and fertilization plans by processing IoT sensor data (soil moisture, meteorological information, etc.) in real time, thereby increasing photosynthetically active radiation utilization efficiency (RUE) by 12%~15%. When coupled with chlorophyll fluorescence remote sensing monitoring and metabolic flux models, a closed-loop control system of "perception-decision-execution" can be constructed to achieve accurate optimization of potato population photosynthetic efficiency. This multidisciplinary research paradigm provides new ideas for breaking through the empirical limitations of traditional agronomy.

7 Future Directions and Research Gaps

7.1 Synergies between genetic and agronomic strategies

The synergistic integration of genetic improvement and agronomic regulation is an important strategy to enhance the photosynthetic efficiency of potatoes. Metabolic flux analysis showed that by synergistically regulating the activity combination of key Calvin cycle enzymes such as Rubisco, FBP aldolase, and SBPase through multiple genes, the net photosynthetic rate can be increased by 28% (Vijayakumar et al., 2023). However, the implementation of these genetic gains relies on precise environmental regulation: variable fertilization techniques based on nitrogen dynamic monitoring can significantly improve the nitrogen use efficiency (NUE) of transgenic plants, thereby supporting their enhanced photosynthetic carbon assimilation potential (Tiwari et al., 2018; Wang et al., 2020). In addition, high-throughput phenotype omics technology provides a new perspective for analyzing the genetic basis of photosynthetic efficiency. The natural variation sites identified through techniques such as chlorophyll fluorescence imaging can guide molecular design breeding, optimize agronomic management thresholds, and maximize the "genotype environment" interaction effect (Van Bezouw et al., 2019). This multi-scale integration strategy provides a systematic solution for targeted improvement of potato photosynthetic performance.

7.2 Challenges in translating lab-based improvements to field conditions

The core challenge facing research on improving potato photosynthetic efficiency is the transformation of laboratory genetic improvement results into field production systems. There are significant differences between the controlled environment of the laboratory and the actual growth conditions in the field. The latter involves dynamic fluctuations of multiple environmental factors such as light intensity, diurnal temperature changes, and water supply, all of which affect the expression stability of photosynthetic genes (Sakoda et al., 2022). More complicatedly, the interaction effect of genotype-environment-management (G×E×M) will significantly regulate the actual performance of genetic improvement. For example, the photosynthetic gain of Rubisco activase-overexpressing lines may be completely inhibited under water stress conditions (Cooper et al., 2021). Solving this transformation bottleneck requires: (1) establishing a predictive model that integrates physiological parameters and environmental variables, and verifying the stability of genetic improvement through multi-location and multi-year field trials; (2) breaking through the technical limitations of multi-gene collaborative editing and developing a precise genetic manipulation system that can be applied on a large scale (Vijayakumar et al., 2023). These studies will provide theoretical basis and methodological support for overcoming the barriers to "laboratory-field" transformation.

7.3 Long-term sustainability and global food security considerations

Improving the photosynthetic efficiency of potatoes is an important scientific proposition in the fields of plant physiology and crop genetic improvement. Its research value is not only reflected in the basic theoretical level, but also closely related to the sustainable development of global agriculture and food security. Against the backdrop of sustained population growth, the traditional yield increasing model relying on variety improvement and agronomic optimization has gradually approached its biological limit (Long et al., 2015), and the efficiency improvement through photosynthetic pathways provides new theoretical basis and technical pathways for achieving yield breakthroughs. It is worth noting that innovative research in this field must take into account ecological benefit assessment, such as optimizing nitrogen use efficiency (NUE), which can significantly increase tuber yield and effectively reduce the risks of soil acidification and water eutrophication caused by excessive fertilization (Wang et al., 2020; Tiwari et al., 2020). The application of genome editing technology, such as the CRISPR/Cas9 system, further breaks through the limitations of traditional transgenic technology by precisely modifying photosynthesis related genes without introducing exogenous DNA fragments, making high-yield varieties more in line with current regulatory requirements and social acceptance (Hameed et al., 2018). Future research should focus on building a collaborative optimization system between genetic improvement and agronomic measures, with a particular emphasis on addressing the bottleneck of converting laboratory results into field applications. Through interdisciplinary and integrated systematic research, the ultimate goal is to achieve a dual breakthrough in potato varieties in terms of yield potential and environmental adaptability, providing sustainable solutions to global food security challenges.

8 Concluding Remarks

This review systematically describes the multi-dimensional strategies for improving the photosynthetic efficiency of potato. Studies have shown that heterologous expression of the Arabidopsis light signal regulator AtBBX21 gene can significantly enhance the stability of the plant's photosystem II under high light stress, increase the net photosynthetic rate by 23%~28%, and ensure that the water use efficiency is not affected by maintaining the optimization of stomatal conductance, ultimately achieving a 15%~20% increase in tuber yield. The kinetic model based on metabolic flux analysis further revealed that by synergistically regulating the expression levels of Calvin cycle rate-limiting enzymes such as Rubisco activase, fructose-1,6-bisphosphate aldolase (FBP aldolase) and sedoheptulose-1,7-bisphosphatase (SBPase), the CO₂ assimilation efficiency of potato can be increased by 28%, which provides a clear target for molecular design breeding of photosynthesis. These findings have laid an important foundation for breaking through the theoretical limit of photosynthetic efficiency of C3 crops.

The development and utilization of natural genetic variation as a potential resource pool for enhancing photosynthetic efficiency is still insufficient, while quantitative trait locus (QTL) mapping research is gradually elucidating the genetic regulatory network of photosynthetic related traits. However, studies have shown that overexpression of specific genes, such as the PsbS gene that regulates the non photochemical quenching (NPQ) pathway, may lead to a decrease in photosynthetic efficiency and tuber yield under dynamic light conditions, revealing the complexity and systematicity of genetic modifications. Meanwhile, the synergistic regulation of photosynthetic carbon assimilation and stomatal conductance plays a decisive role in optimizing carbon water balance under field conditions, which requires genetic improvement strategies to integrate the interaction mechanisms of multiple physiological processes. It is worth noting that the collaborative transformation strategy based on multi gene network regulation has shown significant potential in achieving synergistic improvement of photosynthetic performance and water use efficiency, providing new ideas for breaking through the limitations of single trait improvement.

Future research should focus on multi gene collaborative regulation strategies to systematically break through the multiple limiting factors of photosynthesis. Compared to single gene modification, this integrated approach exhibits a more significant synergistic effect in improving photosynthetic efficiency and water use efficiency. By combining high-throughput phenotype platform with forward genetic screening, the allelic variations of photosynthetic related traits in potato germplasm resources can be systematically analyzed, providing valuable genetic loci for molecular design breeding. At the technical application level, it is crucial to develop precise phenotype systems such as aerosol culture for quantitative analysis of key traits of nitrogen use efficiency (NUE). This technology can accurately identify functional genes that regulate nitrogen assimilation and transport. At the same time, based on the differential response characteristics of different genotypes to the increase of CO₂ concentration, a variety screening system suitable for future climate can be established to optimize the matching efficiency between photosynthetic carbon assimilation and tuber yield formation. By integrating cutting-edge technologies such as genetic improvement guided by multi omics, high-precision phenotype omics, and natural variation mining, a systematic solution for improving potato photosynthetic efficiency will be constructed. This will not only break through the existing yield bottleneck, but also promote the innovative development of resource-saving agricultural models.

Acknowledgments

We are grateful to Dr. Liu for critically reading the manuscript and providing valuable feedback that improved the clarity of the text. We express our heartfelt gratitude to the two anonymous reviewers for their valuable comments on the manuscript.

Conflict of Interest Disclosure

The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

References

Bai H., Liu H., Chen X., Hu R., Li M., He W., Du J., Liu Z., Qin A., Lam J., Kwok R., and Tang B., 2020, Augmenting photosynthesis through facile AIEgen-chloroplast conjugation and efficient solar energy utilization, Materials Horizons, 8(5): 1433-1438.

https://doi.org/10.26434/chemrxiv.13347353.v1

Cooper M., Voss-Fels K., Messina C., Tang T., and Hammer G., 2021, Tackling G × E × M interactions to close on-farm yield-gaps: creating novel pathways for crop improvement by predicting contributions of genetics and management to crop productivity. TAG, Theoretical and Applied Genetics. Theoretische Und Angewandte Genetik, 134: 1625-1644.

https://doi.org/10.1007/s00122-021-03812-3

Crocco C., Ocampo G., Ploschuk E., Mantese A., and Botto J., 2018, Heterologous expression of AtBBX21 enhances the rate of photosynthesis and alleviates photoinhibition in Solanum tuberosum1, Plant Physiology, 177: 369-380.

https://doi.org/10.1104/pp.17.01417

Dahal K., Milne M., and Gervais T., 2023, The enhancement of photosynthetic performance, water use efficiency and potato yield under elevated CO₂ is cultivar dependent, Frontiers in Plant Science, 14: 1287825.

https://doi.org/10.3389/fpls.2023.1287825

Éva C., Oszvald M., and Tamás L., 2019, Current and possible approaches for improving photosynthetic efficiency, Plant Science : an International Journal of Experimental Plant Biology, 280: 433-440.

https://doi.org/10.1016/j.plantsci.2018.11.010

Flexas J., 2016, Genetic improvement of leaf photosynthesis and intrinsic water use efficiency in C3 plants: Why so much little success? Plant Science : an International Journal of Experimental Plant Biology, 251: 155-161.

https://doi.org/10.1016/j.plantsci.2016.05.002

Galmés J., Capó-Bauçà S., Niinemets Ü., and Iñiguez C., 2019, Potential improvement of photosynthetic CO₂ assimilation in crops by exploiting the natural variation in the temperature response of Rubisco catalytic traits, Current Opinion in Plant Biology, 49: 60-67.

https://doi.org/10.1016/j.pbi.2019.05.002

Giessen T., and Silver P., 2017, Engineering carbon fixation with artificial protein organelles, Current Opinion in Biotechnology, 46: 42-50.

https://doi.org/10.1016/j.copbio.2017.01.004

Gitari H., Karanja N., Gachene C., Kamau S., Sharma K., and Schulte-Geldermann E., 2018, Nitrogen and phosphorous uptake by potato (Solanum tuberosum L.) and their use efficiency under potato-legume intercropping systems, Field Crops Research, 222: 78-84.

https://doi.org/10.1016/J.FCR.2018.03.019

Hameed A., Zaidi S., Shakir S., and Mansoor S., 2018, Applications of new breeding technologies for potato improvement, Frontiers in Plant Science, 9.

https://doi.org/10.3389/fpls.2018.00925

Hussain S., Ulhassan Z., Brestič M., Živčák M., Zhou W., Allakhverdiev S., Yang X., Safda M., Yang W., and Liu W., 2021, Photosynthesis research under climate change, Photosynthesis Research, 150: 5-19.

https://doi.org/10.1007/s11120-021-00861-z

Iñiguez C., Aguiló-Nicolau P., and Galmés J., 2021, Improving photosynthesis through the enhancement of Rubisco carboxylation capacity, Biochemical Society Transactions, 49(5): 2007-2019.

https://doi.org/10.1042/BST20201056

Karlusich J., Arce R., Shahinnia F., Sonnewald S., Sonnewald U., Zurbriggen M., Hajirezaei M., and Carrillo N., 2020, Transcriptional and metabolic profiling of potato plants expressing a plastid-targeted electron shuttle reveal modulation of genes associated to drought tolerance by chloroplast redox poise, International Journal of Molecular Sciences, 21(19): 7199.

https://doi.org/10.3390/ijms21197199

Koch M., Naumann M., Pawelzik E., Gransee A., and Thiel H., 2019, The importance of nutrient management for potato production part I: plant nutrition and yield, Potato Research, 63: 97-119.

https://doi.org/10.1007/s11540-019-09431-2

Lehretz G., Schneider A., Leister D., and Sonnewald U., 2022, High non-photochemical quenching of VPZ transgenic potato plants limits CO₂ assimilation under high light conditions and reduces tuber yield under fluctuating light,Journal of Integrative Plant Biology, 64(9): 1821-1832.

https://doi.org/10.1111/jipb.13320

Li H., Mei X., Wang J., Huang F., Hao W., and Li B., 2021, Drip fertigation significantly increased crop yield, water productivity and nitrogen use efficiency with respect to traditional irrigation and fertilization practices: a meta-analysis in China, Agricultural Water Management, 244: 106534.

https://doi.org/10.1016/J.AGWAT.2020.106534

Liu S., Liu T., Wang E., Cheng Y., Liu T., Chen G., Guo M., and Song B., 2022, Dissecting the chloroplast proteome of the potato (Solanum tuberosum L.) and its comparison with the tuber amyloplast proteome, Plants, 11(15): 1915.

https://doi.org/10.3390/plants11151915

Long S., Marshall-Colón A., and Zhu X., 2015, Meeting the global food demand of the future by engineering crop photosynthesis and yield potential, Cell, 161: 56-66.

https://doi.org/10.1016/j.cell.2015.03.019

Manning T., Birch R., Stevenson T., Nugent G., and Whitney S., 2023, Bacterial form II Rubisco can support wild-type growth and productivity in Solanum tuberosum cv. Desiree (potato) under elevated CO₂, PNAS Nexus, 2(2): pgac305.

https://doi.org/10.1093/pnasnexus/pgac305

Nowicka B., Ciura J., Szymańska R., and Kruk J., 2018, Improving photosynthesis, plant productivity and abiotic stress tolerance - current trends and future perspectives, Journal of Plant Physiology, 231: 415-433.

https://doi.org/10.1016/j.jplph.2018.10.022

Nyawade S., Karanja N., Gachene C., Gitari H., Schulte-Geldermann E., and Parker M., 2019, Intercropping optimizes soil temperature and increases crop water productivity and radiation use efficiency of rainfed potato, American Journal of Potato Research, 96: 457-471.

https://doi.org/10.1007/s12230-019-09737-4

Ocampo G., Ploschuk E., Mantese A., Crocco C., and Botto J., 2021, BBX21 reduces ABA sensitivity, mesophyll conductance and chloroplast electron transport capacity to increase photosynthesis and water use efficient in potato plants cultivated under moderated drought, The Plant Journal : for Cell and Molecular Biology, 108(4): 1131-1144.

https://doi.org/10.1111/tpj.15499

Sakoda K., Adachi S., Yamori W., and Tanaka Y., 2022, Towards improved dynamic photosynthesis in C3 crops by utilising natural genetic variation, Journal of Experimental Botany, 73(10): 3109-3121.

https://doi.org/10.1093/jxb/erac100

Santana I., Jeon S., Kim H., Islam M., Castillo C., Garcia G., Newkirk G., and Giraldo J., 2022, Targeted carbon nanostructures for chemical and gene delivery to plant chloroplasts, ACS nano, 16(8): 12156-12173.

https://doi.org/10.1021/acsnano.2c02714

Sharwood R., Ghannoum O., and Whitney S., 2016, Prospects for improving CO₂ fixation in C3-crops through understanding C4-Rubisco biogenesis and catalytic diversity, Current Opinion in Plant Biology, 31: 135-142.

https://doi.org/10.1016/j.pbi.2016.04.002

Shrestha B., Darapuneni M., Stringam B., Lombard K., and Djaman K., 2023, Irrigation water and nitrogen fertilizer management in potato (Solanum tuberosum L.): a review, Agronomy, 13(10): 2566.

https://doi.org/10.3390/agronomy13102566

Tao J., and Han J.Q., 2024, Physiological mechanisms of photosynthesis and antioxidant system in rice under high temperature stress, Rice Genomics and Genetics, 15(1): 36-47.

https://doi.org/10.5376/rgg.2024.15.0005

Theeuwen T., Logie L., Harbinson J., and Aarts M., 2022, Genetics as a key to improving crop photosynthesis, Journal of Experimental Botany, 73: 3122-3137.

https://doi.org/10.1093/jxb/erac076

Tiwari J., Devi S., Buckseth T., Ali N., Singh R., Zinta R., Dua V., and Chakrabarti S., 2020, Precision phenotyping of contrasting potato (Solanum tuberosum L.) varieties in a novel aeroponics system for improving nitrogen use efficiency: in search of key traits and genes, Journal of Integrative Agriculture, 19, 51-61.

https://doi.org/10.1016/s2095-3119(19)62625-0

Tiwari J., Plett D., Garnett T., Chakrabarti S., and Singh R., 2018, Integrated genomics, physiology and breeding approaches for improving nitrogen use efficiency in potato: translating knowledge from other crops, Functional Plant Biology: FPB, 45(6): 587-605.

https://doi.org/10.1071/FP17303

Van Bezouw R., Keurentjes J., Harbinson J., and Aarts M., 2019, Converging phenomics and genomics to study natural variation in plant photosynthetic efficiency, The Plant Journal, 97: 112-133.

https://doi.org/10.1111/tpj.14190

Vijayakumar S., Wang Y., Lehretz G., Taylor S., Carmo‐Silva E., and Long S., 2023, Kinetic modeling identifies targets for engineering improved photosynthetic efficiency in potato (Solanum tuberosum cv. Solara), The Plant Journal : for Cell and Molecular Biology., 117(2): 561-572

https://doi.org/10.1111/tpj.16512

Wang C., Zang H., Liu J., Shi X., Li S., Chen F., and Chu Q., 2020, Optimum nitrogen rate to maintain sustainable potato production and improve nitrogen use efficiency at a regional scale in China. a meta-analysis, Agronomy for Sustainable Development, 40: 37.

https://doi.org/10.1007/s13593-020-00640-5