GSE38894
Global analysis of the sugarcane microtranscriptome reveals a unique composition of small RNAs associated with axillary bud outgrowth
Axillary bud outgrowth determines plant shoot architecture and is under control of endogenous hormones and a fine-tuned gene expression network. Some genes associated with shoot development are known targets of small RNAs (sRNAs). Although it is well known that sRNAs act broadly in plant development, our understanding about their roles in vegetative bud outgrowth remains limited. Moreover, the expression profiles of microRNAs (miRNAs) and their targets in axillary buds are unknown. In this study, we employed next-generation sequencing, gene expression analysis and metabolite profiling to identify sRNAs and quantify distinct hormones, respectively, in vegetative axillary buds of the tropical biofuel crop sugarcane (Saccharum spp.). Differential accumulation of abscisic acid (ABA), gibberellins (GA), and cytokinins indicates a dynamic balance of these hormones during sugarcane bud outgrowth. A number of repeat-associated siRNAs generated from distinct transposable elements and genes were highly expressed in both inactive and developing buds. RT-qPCR results revealed that specific miRNAs were differentially expressed in developing buds and some correlate negatively with the expression of their targets. Expression patterns of miR159 and its experimentally confirmed target GAMYB suggest they play roles in regulating ABA and GA-signaling pathways during bud outgrowth. Our work reveals, for the first time, differences in composition and expression profiles of small RNAs and targets between inactive and developing buds that, together with the endogenous balance of specific hormones, may be important to regulate axillary bud outgrowth in plants. Overall design: Examination of small RNA populations in vegetative axillary buds of the tropical biofuel crop sugarcane (Saccharum spp.)