The miR408 expression in scutellum derived somatic embryos of Oryza sativa L. ssp. indica varieties: media and regenerating embryos

Abstract

The conserved miRNAs are key players for post-transcriptional control of gene expression for plant growth and development. The overexpression of miR408 is reported to show improvement in biomass and photosynthesis in Oryza sativa. Also, microarray data show differential expression in somatic and regenerating embryos of japonica rice. The position weight matrix analyses of miR408 (72 sequences) family in plant kingdom was performed using DAMBE and targets were obtained by psRNATarget. The qRT-PCR experiments were performed using stem-loop primers to evaluate the role of miR408-3p and targets in seven different indica rice varieties, the formation of regenerating pluripotent somatic embryos and assessment of suitable conditions for generation of somatic embryos. Different callus induction media and regeneration media, healthy calli, brown calli and necrotic calli were also used to assess the expression of miR408-3p and its targets. The conserved sequence of miR408-3p was observed and 68 targets were identified using psRNATarget in Oryza sativa. The qRT-PCR was performed on target Uclacyanin which shows mismatch at position 14 and 15, and RNA polymerase II at position 14 and 17. The miR408-3p expression shows recalcitrant > moderately recalcitrant > non-recalcitrant in indica rice variety. Significant differences in the expression of miR408-3p for the developing somatic embryos at 10-day, 15-day, 20-day, 25-day and 30-day old somatic embryos were observed. Evidences for miR408-3p expression and identification of new target RNA Polymerase II is shown. The lower expression of miR408-3p shows parallelism with the generation of healthy somatic embryos with applications for rapid screening of pluripotency in Oryza sativa.