An Insight Into Pentatricopeptide-Mediated Chloroplast Necrosis via microRNA395a During Rhizoctonia solani Infection.

Sheath blight (ShB) disease, caused by Rhizoctonia solani, is one of the major biotic stress-oriented diseases that adversely affect the rice productivity worldwide. However, the regulatory mechanisms are not understood yet comprehensively. In the current study, we had investigated the potential roles of miRNAs in economically important indica rice variety Pusa Basmati-1 upon R. solani infection by carrying out in-depth, high-throughput small RNA sequencing with a total data size of 435 million paired-end raw reads from rice leaf RNA samples collected at different time points. Detailed data analysis revealed a total of 468 known mature miRNAs and 747 putative novel miRNAs across all the libraries. Target prediction and Gene Ontology functional analysis of these miRNAs were found to be unraveling various cellular, molecular, and biological functions by targeting various plant defense-related genes. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to validate the miRNAs and their putative target genes. Out of the selected miRNA-specific putative target genes, miR395a binding and its cleavage site on pentatricopeptide were determined by 5' RACE-PCR. It might be possible that R. solani instigated chloroplast degradation by modulating the pentatricopeptide which led to increased susceptibility to fungal infection.

DNA N6-Methyladenine Modification in Plant Genomes-A Glimpse into Emerging Epigenetic Code.

N6-methyladenine (6mA) is a DNA base modification at the 6th nitrogen position; recently, it has been resurfaced as a potential reversible epigenetic mark in eukaryotes. Despite its existence, 6mA was considered to be absent due to its undetectable level. However, with the new advancements in methods, considerable 6mA distribution is identified across the plant genome. Unlike 5-methylcytosine (5mC) in the gene promoter, 6mA does not have a definitive role in repression but is exposed to have divergent regulation in gene expression. Though 6mA information is less known, the available evidences suggest its function in plant development, tissue differentiation, and regulations in gene expression. The current review article emphasizes the research advances in DNA 6mA modifications, identification, available databases, analysis tools and its significance in plant development, cellular functions and future perspectives of research.