The Role of Chloroplast Gene Expression in Plant Responses to Environmental Stress

Abstract

Chloroplasts are plant organelles that carry out photosynthesis, produce various metabolites, and sense changes in the external environment. Given their endosymbiotic origin, chloroplasts have retained independent genomes and gene-expression machinery. Most genes from the prokaryotic ancestors of chloroplasts were transferred into the nucleus over the course of evolution. However, the importance of chloroplast gene expression in environmental stress responses have recently become more apparent. Here, we discuss the emerging roles of the distinct chloroplast gene expression processes in plant responses to environmental stresses. For example, the transcription and translation of psbA play an important role in high-light stress responses. A better understanding of the connection between chloroplast gene expression and environmental stress responses is crucial for breeding stress-tolerant crops better able to cope with the rapidly changing environment.

Light acts as a stressor and influences abiotic and biotic stress responses in plants

“…However, this review will mainly focus on the photoreceptors. Readers may refer to Fernandez and Strnad (2008); Crawford, Lehotai, and Strand (2018) and Zhang, Zhang, Li, and Lu (2020) for a broader description of the role of plastids in responses to stress.…”

Organelle Genetics in Plants

“…In this Special Issue “Organelle Genetics in Plants,” 11 articles were accepted with four reviews and seven original research articles covering outstanding advances in different chloroplast and plant mitochondria research fields ( Table 1 ). These works focus on topics related to organellar gene expression (OGE) (chloroplast RNA editing in soybean [ 5 ], mitochondria RNA editing and intron splicing in soybean during nodulation [ 6 ] and the roles of transcriptional and post-transcriptional regulation of OGE in responses to environmental stress [ 7 , 8 ]); the analysis of nuclear integrants of mitochondrial DNA (NUMTs) or plastid DNA (NUPTs) [ 9 ]; the sequencing and characterization of organellar genomes (the mitogenomes of common bean [ 10 ] and four Trifolium species [ 11 ], and the chloroplast genomes (plastomes) of Trentepohlia odorata [ 12 ], three Utricularia amethystina morphotypes [ 13 ], and three plant parasitic Macrosolen species [ 14 ]); and finally, the most recent advances in plastid genome engineering [ 15 ]. In this editorial, we sum up the main findings of these eleven insightful manuscripts.…”

“…Two reviews are about the emerging importance of OGE processes in plant responses to environmental stress. Quesada and Robles [ 7 ] and Zhang et al [ 8 ] compile the results hitherto published from analyzing plant mutants, mainly in Arabidopsis and rice, revealing a connection between OGE and tolerance to environmental stress. Our review [ 7 ] summarizes the works reporting the phenotypic and molecular analyses of plant mutants exhibiting altered sensitivity to salinity that are affected in nuclear genes involved in OGE regulation at transcriptional or post-transcriptional levels.…”

“…We conclude that the detailed characterization of these mutants strongly supports a link between OGE and plant salt tolerance, likely through organelle-to-nucleus signaling, and highlights the important role of chloroplast and mitochondrion homeostasis in plant adaptation to salinity. Following a similar approach, Zhang et al [ 8 ] focus on the published works reporting a link between plant environmental stress responses and: (i) the transcriptional control of chloroplast gene expression; (ii) RNA metabolism in chloroplast; (iii) translation in this organelle. Together these studies indicate that chloroplast gene expression is important for plant stress responses, and the authors propose that novel tools like CRISPR/Cas9, RNA interference, and artificial RNA editing systems for carrying out the RNA editing of specific sites in chloroplasts should be developed to better investigate the molecular mechanisms of chloroplast gene expression in response to environmental cues.…”

Roles of Si and SiNPs in Improving Thermotolerance of Wheat Photosynthetic Machinery via Upregulation of PsbH, PsbB and PsbD Genes Encoding PSII Core Proteins

“…It was observed that PSII is generally more sensitive to temperature stress [20] compared to PSI [21]. Indeed, plants deal with environmental stresses by regulating the expression of some stress-responsive genes [22]. Heat stress induces alterations in protein factors that are involved in de novo assembly and/or degradation and turnover of the of PSII reaction center proteins.…”