Involvement of miR164- and miR167-mediated target gene expressions in responses to water deficit in cassava

Abstract

Cassava (Manihot esculenta Crantz) is an important crop and it is significantly affected by water stress. The computational analysis of cis-regulatory elements in promoter regions of 21 drought-responsive miRNA gene families and 35 miRNA-target genes in cassava indicated some elements relevant to drought stress responses. To investigate the role of miRNAs and target genes in responses to a water deficit in cassava in more detail, in vitro plantlets were subjected to an imitated water deficit by 40 % polyethylene glycol. Using RT-qPCR, the differential expression of the cassava miR164/MesNAC and miR167/MesARF6/8 were observed to be associated with changes in the leaf shape, stomatal closure, and relative water content. The modified 5'-RNA ligase-mediated rapid amplification of cDNA-end (5'RLM-RACE) experiment confirmed MesNAC and MesARF8 as the in vivo-target genes of miR164 and miR167, respectively, in cassava leaf. The possible functions of miR164 and miR167-target genes in response to water deficit are discussed.