Back to the past: Improving photosynthesis with cyanobacterial genes

Abstract

Higher yields and more stress-tolerant crops will be required to meet the increasing demand for food production that is expected to double by 2050. Genetic engineering strategies aimed to improve yield and stress tolerance have focused primarily on overexpression of endogenous plant genes belonging to molecular networks involved in stress perception or responses. However, this approach is limited by the genetic stock of extant plant species and by the unwanted consequences of gene silencing. In this context, cyanobacteria appear as an interesting alternative as they share many metabolic pathways with plant cells, especially with those in the chloroplast, offering a vast source of genes for genetic engineering of higher plants. During evolution, a number of cyanobacterial ancestor genes involved in stress tolerance have disappeared from plant genomes, raising the possibility of recovering these adaptive advantages by reintroducing those genes into plants. In this chapter, we summarize examples where this strategy has been successfully applied, especially by modifying the photosynthetic electron transport chain. Data mining in cyanobacterial genomes could offer a significant biotechnological tool for designing plants with higher productivity and improved performance under environmental stresses.