Chloroplast gene expression: Recent advances and perspectives

Chloroplasts evolved from an ancient cyanobacterial endosymbiont more than 1.5 billion years ago. During subsequent coevolution with the nuclear genome, the chloroplast genome has remained independent, albeit strongly reduced, with its own transcriptional machinery and distinct features, such as chloroplast-specific innovations in gene expression and complicated post-transcriptional processing. Light activates the expression of chloroplast genes via mechanisms that optimize photosynthesis, mini -mize photodamage, and prioritize energy investments. Over the past few years, studies have moved from describing phases of chloroplast gene expression to exploring the underlying mechanisms. In this re-view, we focus on recent advances and emerging principles that govern chloroplast gene expression in land plants. We discuss engineering of pentatricopeptide repeat proteins and its biotechnological effects on chloroplast RNA research; new techniques for characterizing the molecular mechanisms of chloroplast gene expression; and important aspects of chloroplast gene expression for improving crop yield and stress tolerance. We also discuss biological and mechanistic questions that remain to be answered in the future.

Automated summary

Chloroplasts evolved from a cyanobacterial endosymbiont and have their own independent genome with unique features. Light activates chloroplast gene expression to optimize photosynthesis, minimize photodamage, and allocate energy. Recent research has shifted from describing chloroplast gene expression to exploring the underlying mechanisms.