Essential role of γ-clade RNA-dependent RNA polymerases in rice development and yield-related traits is linked to their atypical polymerase activities regulating specific genomic regions.
|Title||Essential role of γ-clade RNA-dependent RNA polymerases in rice development and yield-related traits is linked to their atypical polymerase activities regulating specific genomic regions.|
|Publication Type||Journal Article|
|Year of Publication||2021|
|Authors||Jha V, Narjala A, Basu D, Sujith TN, Pachamuthu K, Chenna S, Nair A, Shivaprasad PV|
|Date Published||2021 Aug 27|
RNA-dependent RNA polymerases (RDR) generate double-stranded (ds)RNA triggers for RNA silencing across eukaryotes. Among the three clades, α- and β-clade members are key components of RNA silencing and mediators of stress responses across eukaryotes. However, γ-clade members are unusual in that they are represented in phylogenetically distant plants and fungi, and their functions are unknown. Using genetic, bioinformatic and biochemical methods, we show that γ-clade RDRs from Oryza sativa L. are involved in plant development as well as regulation of expression of coding and non-coding RNAs. Overexpression of γ-clade RDRs in transgenic rice and tobacco plants resulted in robust growth phenotype, whereas their silencing in rice displayed strong inhibition of growth. Small (s)RNA and RNA-seq analysis of OsRDR3 mis-expression lines suggested that it is specifically involved in the regulation of repeat-rich regions in the genome. Biochemical analysis confirmed that OsRDR3 has robust polymerase activities on both single stranded (ss)RNA and ssDNA templates similar to the activities reported for α-clade RDRs such as AtRDR6. Our results provide the first evidence of the importance of γ-clade RDRs in plant development, their atypical biochemical activities, and their contribution to the regulation of gene expression.
|Alternate Journal||New Phytol|