Transcription Profile Analysis of Chlorophyll Biosynthesis in Leaves of Wild-Type and Chlorophyll b-Deficient Rice (Oryza sativa L.)

Abstract

Photosynthesis is an essential biological process and a key approach for raising crop yield. However, photosynthesis in rice is not fully investigated. This study reported the photosynthetic properties and transcriptomic profiles of chlorophyll (Chl) b-deficient mutant (ch11) and wild-type rice (Oryza sativa L.). Chl b-deficient rice revealed irregular chloroplast development (indistinct membranes, loss of starch granules, thinner grana, and numerous plastoglobuli). Next-generation sequencing approach application revealed that the differential expressed genes were related to photosynthesis machinery, Chl-biosynthesis, and degradation pathway in ch11. Two genes encoding PsbR (PSII core protein), FtsZ1, and PetH genes, were found to be down-regulated. The expression of the FtsZ1 and PetH genes resulted in disrupted chloroplast cell division and electron flow, respectively, consequently reducing Chl accumulation and the photosynthetic capacity of Chl b-deficient rice. Furthermore, this study found the up-regulated expression of the GluRS gene, whereas the POR gene was down-regulated in the Chl biosynthesis and degradation pathways. The results obtained from RT-qPCR analyses were generally consistent with those of transcription analysis, with the exception of the finding that MgCH genes were up-regulated which enhance the important intermediate products in the Mg branch of Chl biosynthesis. These results indicate a reduction in the accumulation of both Chl a and Chl b. This study suggested that a decline in Chl accumulation is caused by irregular chloroplast formation and down-regulation of POR genes; and Chl b might be degraded via the pheophorbide b pathway, which requires further elucidation.

Chlorophyll contents and expression profiles of photosynthesis-related genes in water-stressed banana plantlets

“…Alterations of gene expressions that responsible for chlorophyll biosynthesis seemed to cause the decrease of chlorophyll content in leaf tissues of banana plantlets exposed to PEG. Similar result in rice seedling and potato that drought stress also changed the expressions of PORA and PORB genes (Chen et al 2020;Nguyen et al 2021).…”

QTL Analysis for Chlorophyll Content in Strawberry (Fragaria × ananassa Duch.) Leaves

“…In this study, PPR coding gene was also predicted among the candidate genes. Among other candidate genes, Chaperone protein dnaJ, Calvin cycle protein CP12-2, Phospholipase A1 PLIP2, Senescence-associated protein, Peroxiredoxin, Heat shock protein 90-5-encoding genes were predicted, which have been reported to be involved in chlorophyll biosynthesis directly and indirectly [55,[59][60][61][62]. However, further studies, including fine mapping of the loci, expression analysis, gene knock-out and gene cloning, are required to determine the strong candidate gene.…”

Morphological, physiological, and transcriptional responses of the freshwater diatom Fragilaria crotonensis to elevated pH conditions

“…In contrast, genes within the carotenoid biosynthesis pathway such as Zeaxanthin epoxidase (ZEP) and violaxanthin de-epoxidase (VDE) decreased in representation at high pH. Regarding photosynthetic metabolism, ferredoxin NADP + reductase (petH) and photosystem I subunit VII (psaC), which are both involved in the final step of electron transfer from ferredoxin PSI to NADPH to fuel the Calvin cycle (Fischer et al, 1998;Nguyen et al, 2021), decreased in relative expression at pH 9.2. Genes involved in oxidative stress such as redoxin (PRDX5) (Hopkins and Neumann, 2019) and the catalase peroxidase gene (katG.1), which quenches photosynthetically-produced ROS species (Nishiyama et al, 2001), appeared to decrease overall at high pH.…”