Genetic manipulation of photosynthesis to enhance crop productivity under changing environmental conditions

Engineering nitrogen and carbon fixation for next-generation plants

Improving plant nitrogen (N) and carbon (C) acquisition and assimilation is a major challenge for global agriculture, food security, and ecological sustainability. Emerging synthetic biology techniques, including directed evolution, artificial intelligence (AI)-guided enzyme design, and metabolic engineering, have opened new avenues for optimizing nitrogenase to fix atmospheric N2 in plants, engineering Rhizobia or other nitrogen-fixing bacteria for symbiotic associations with both legume and nonlegume crops, and enhancing carbon fixation to improve photosynthetic efficiency and source-to-sink assimilate fluxes. Here, we discuss the potential for engineering nitrogen fixation and carbon fixation mechanisms in plants, from rational and AI-driven optimization of nitrogen and carbon fixation cycles. Furthermore, we discuss strategies for modifying source-to-sink relationships to promote robust growth in extreme conditions, such as arid deserts, saline-alkaline soils, or even extraterrestrial environments like Mars. The combined engineering of N and C pathways promises a new generation of crops with enhanced productivity, resource-use efficiency, and resilience. Finally, we explore future perspectives, focusing on the integration of enzyme engineering via directed evolution and computational design to accelerate metabolic innovation in plants.

Analysis of Photosynthetic Characteristics and Screening High Light-Efficiency Germplasm in Sugarcane

Sugarcane is a globally significant crop for sugar and energy production, and developing high light-efficiency sugarcane varieties is crucial for enhancing yield and quality. However, limited research is available on the screening of sugarcane germplasm with high photosynthetic efficiency, especially with different leaf positions. The present study, conducted in Guangxi, China, aimed to analyze the photosynthetic characteristics of 258 sugarcane varieties at different leaf positions over three consecutive years in field experiments. The results showed significant differences in photosynthetic characteristics among genotypes, years, and leaf positions. Heritability estimates for various photosynthetic parameters ranged from 0.76 to 0.88. Principal component analysis revealed that the first three principal components accounted for over 99% of the cumulative variance. The first component represented photosynthetic efficiency and light utilization, the second focused on electron transfer and reaction center status, and the third was associated with chlorophyll content. Cluster and discriminant analysis classified sugarcane genotypes into three categories: high photosynthetic efficiency (HPE) with 86 genotypes, medium photosynthetic efficiency (MPE) with 60 genotypes, and low photosynthetic efficiency (LPE) with 112 genotypes. Multi-year trials confirmed that HPE sugarcane genotypes had higher single-stem weight and sucrose content. This study provides valuable insights into the photosynthetic physiological characteristics of different sugarcane varieties, which can contribute to further research regarding high yields and sugar breeding.

Advances in light system engineering across the phototrophic spectrum

Current work in photosynthetic engineering is progressing along the lines of cyanobacterial, microalgal, and plant research. These are interconnected through the fundamental mechanisms of photosynthesis and advances in one field can often be leveraged to improve another. It is worthwhile for researchers specializing in one or more of these systems to be aware of the work being done across the entire research space as parallel advances of techniques and experimental approaches can often be applied across the field of photosynthesis research. This review focuses on research published in recent years related to the light reactions of photosynthesis in cyanobacteria, eukaryotic algae, and plants. Highlighted are attempts to improve photosynthetic efficiency, and subsequent biomass production. Also discussed are studies on cross-field heterologous expression, and related work on augmented and novel light capture systems. This is reviewed in the context of translatability in research across diverse photosynthetic organisms.