Genetics as a key to improving crop photosynthesis

Abstract

Since the basic biochemical mechanisms of photosynthesis are remarkably conserved among plant species, genetic modification approaches have so far been the main route to improve the photosynthetic performance of crops. Yet, phenotypic variation observed in wild species and between varieties of crop species, implies there is standing natural genetic variation for photosynthesis offering a largely unexplored resource to use for breeding crops with improved photosynthesis and higher yields. The reason this has not been explored yet is that the variation probably involves thousands of genes, each contributing only little to photosynthesis, making them hard to identify without the proper phenotyping and genetic tools. This is changing though, and increasingly more studies report on quantitative trait loci (QTLs) for photosynthetic phenotypes. So far, hardly any of these QTLs are used in marker assisted breeding or genomic selection approaches to improve crop photosynthesis and yield, and hardly ever are the underlying causal genes identified. We propose to take the genetics of photosynthesis to a higher level, and identify the genes and alleles nature has used for millions of years to tune photosynthesis to be in line with local environmental conditions. We will need to determine their physiological function, and design novel strategies to use this knowledge to improve crop photosynthesis through conventional plant breeding, based on readily available crop plant germplasm. In this work, we present and discuss the genetic methods needed to reveal natural genetic variation, and elaborate on how to apply this to improve crop photosynthesis.

Genetic variation in photosynthesis: many variants make light work

“…Whereas genetic variation in photosynthetic traits is significant in many major crop species (reviewed by Sharwood et al , 2022 and Sakoda et al , 2022 in this issue), incorporation of photosynthesis in selective breeding programmes is still rare. Theeuwen et al (2022) discuss how quantitative genetics can be used to discover useful trait variation and design strategies to improve crop photosynthesis, based on readily available crop plant germplasm. Crop breeding strategies require a defined target population of environments (TPE), namely a variable group of future production environments ( Crespo-Herrera et al , 2021 ), under which the breeding programme attempts to enhance crop performance.…”

The NDH complex reveals a trade-off that constrains maximising photosynthesis inArabidopsis thaliana

“…Plant breeding contributed to these yield increases by focusing on improving the light interception index and the harvest index, but has left the efficiency of converting absorbed light energy into biomass, primarily determined by photosynthesis, largely unimproved (Monteith, 1994; Long et al, 2006). In fact, for most staple crops the increase in photosynthetic efficiency has been minimal since the Green Revolution (Long et al, 2015; Theeuwen et al, 2022b). This poses a conundrum; while it has been shown that there is evidence of ample variation for photosynthetic performance in elite breeding lines, this variation does not correlate well with higher yields, the trait often selected for in plant breeding (Driever et al, 2014; Acevedo-Siaca et al, 2020).…”

“…In the case of dynamic properties of NPQ unveiling the genetic variation, i.e. genes and alleles, outlining these differences will generate insights into the physiological processes underlying NPQ and open up novel targets for improving photosynthesis (Theeuwen et al, 2022b). Up to 3000 proteins are involved with photosynthetic functioning, most of which are nuclear encoded and targeted to the chloroplast.…”

Carbon Dots Embedded in Nanoporous SiO2 Nanoparticles for Enhancing Photosynthesis in Agricultural Crops

“…Photosynthesis plays an important role in plant growth and development and has been considered to be closely related to crop yield . So far, gene regulation technology, plant growth regulators, photosynthetic bacteria, and light-harvesting materials (LCMs) have been used to improve crop yield by increasing photosynthesis. − Among them, LCMs can increase the utilization range and efficiency of sunlight, thus improving the photosynthetic activity. , For example, fluorescent g-C 3 N 4 (10 mg·L –1 ) increased photosynthesis (30.0%) in maize by converting ultraviolet (UV) light to blue light. Fluorescent silicon quantum dots (∼30 mg·L –1 ) increased the blue-light absorption of lettuce by 45%, which further promoted photosynthesis.…”