Journal of Energy Bioscience 2024, Vol.15, No.6, 337-348 http://bioscipublisher.com/index.php/jeb 338 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.
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