Integrated Analysis of miRNAs Associated With Sugarcane Responses to Low-Potassium Stress.

Nannan Zhang,Zilin Wu,Yonghong Huang,Jiayun Wu,Xiaoning Gao,Huanzhang Lin,Xiaomin Feng,Yongwen Qi,Qiaoying Zeng

doi:10.3389/fpls.2021.750805

Abstract

Sugarcane is among the most important global crops and a key bioenergy source. Sugarcane production is restricted by limited levels of available soil potassium (K+). The ability of plants to respond to stressors can be regulated by a range of microRNAs (miRNAs). However, there have been few studies regarding the roles of miRNAs in the regulation of sugarcane responses to K+-deficiency. To understand how these non-coding RNAs may influence sugarcane responses to low-K+ stress, we conducted expression profiling of miRNAs in sugarcane roots under low-K+ conditions via high-throughput sequencing. This approach led to the identification of 324 and 42 known and novel miRNAs, respectively, of which 36 were found to be differentially expressed miRNAs (DEMs) under low-K+ conditions. These results also suggested that miR156-x/z and miR171-x are involved in these responses as potential regulators of lateral root formation and the ethylene signaling pathway, respectively. A total of 705 putative targets of these DEMs were further identified through bioinformatics predictions and degradome analyses, and GO and KEGG enrichment analyses revealed these target mRNAs to be enriched for catalytic activity, binding functions, metabolic processes, plant hormone signal transduction, and mitogen-activated protein kinase (MAPK) signaling. In summary, these data provide an overview of the roles of miRNAs in the regulation of sugarcane response to low-K+ conditions.

Highlights

Potassium is a key nutrient essential for the growth and development of plants (Maathuis, 2009), with potassium ions (K+) being present at high levels within cells wherein they regulate osmotic pressure and control the activation of key enzymes including those associated with photosynthesis (Clarkson and Hanson, 1980), protein synthesis, stomatal closure (Chérel and Gaillard, 2019), osmoregulation, phloem transport (Patrick et al, 2001), and a range of other processes (Leigh and Wyn Jones, 1984)
We began by conducting the high-throughput sequencing of miRNAs identified in sugarcane roots exposed to low-K+ levels (0.1 mM K+) for 0, 6, 12, 24, 48, and 72 h
Clean reads were aligned to small RNAs included in the Rfam and Genebank databases using the Bowtie tools, after which all ribosomal RNA, transfer RNA, small nuclear RNA, and small nucleolar RNA were removed, as were other non-coding RNA

Summary

Introduction

Potassium is a key nutrient essential for the growth and development of plants (Maathuis, 2009), with potassium ions (K+) being present at high levels within cells wherein they regulate osmotic pressure and control the activation of key enzymes including those associated with photosynthesis (Clarkson and Hanson, 1980), protein synthesis, stomatal closure (Chérel and Gaillard, 2019), osmoregulation, phloem transport (Patrick et al, 2001), and a range of other processes (Leigh and Wyn Jones, 1984). It is vital that the genetics and regulation of plant low-K+ stress responses be studied in detail to facilitate the development of more K+-efficient crop cultivars

Methods

Results

Conclusion