miRNA and mRNA Expression Profiles Reveal Insight into Chitosan-Mediated Regulation of Plant Growth

Chitosan has been numerously studied as a plant growth regulator and stress tolerance inducer. To investigate the roles of chitosan as bioregulator on plant and unravel its possible metabolic responses mechanisms, we simultaneously investigated mRNAs and microRNAs (miRNAs) expression profiles of wheat seedlings in response to chitosan heptamer. We found 400 chitosan-responsive differentially expressed genes, including 268 up-regulated and 132 down-regulated mRNAs, many of which were related to photosynthesis, primary carbon and nitrogen metabolism, defense responses, and transcription factors. Moreover, miRNAs also participate in chitosan-mediated regulation on plant growth. We identified 87 known and 21 novel miRNAs, among which 56 miRNAs were induced or repressed by chitosan heptamer, such as miRNA156, miRNA159a, miRNA164, miRNA171a, miRNA319, and miRNA1127. The integrative analysis of miRNA and mRNA expression profiles in this case provides fundamental information for further investigation of regulation mechanisms of chitosan on plant growth and will facilitate its application in agriculture.壳聚糖（chitosan）作为植物生长调节剂与胁迫耐受诱导剂已被大量研究。为探究壳聚糖作为植物生物调节剂的作用，并阐明其潜在的代谢响应机制，本研究同时分析了小麦幼苗响应七聚体壳聚糖的信使RNA（messenger RNA, mRNA）与微小RNA（microRNA, miRNA）表达谱。本研究共鉴定得到400个壳聚糖响应的差异表达基因，其中268个为上调表达的mRNA、132个为下调表达的mRNA，此类基因多与光合作用、初级碳氮代谢、防御响应及转录因子相关。此外，miRNA亦参与壳聚糖介导的植物生长调控过程。本研究鉴定得到87个已知miRNA与21个新发现miRNA，其中56个miRNA的表达可被七聚体壳聚糖诱导或抑制，例如miRNA156、miRNA159a、miRNA164、miRNA171a、miRNA319及miRNA1127。本研究对miRNA与mRNA表达谱的整合分析，为进一步探究壳聚糖调控植物生长的机制提供了基础信息，也将推动其在农业领域的应用。