Identification and comparative analysis of differentially expressed miRNAs in leaves of two wheat (Triticum aestivum L.) genotypes during dehydration stress.

Xingli Ma,Zhiqiang Wang,Liru Cao,Xiaoyang Guo,Shulei Guo,Tongbao Lin,Zeyu Xin,Qinghua Yang

doi:10.1186/s12870-015-0413-9

Abstract

BackgroundMicroRNAs (miRNAs) play critical roles in the processes of plant growth and development, but little is known of their functions during dehydration stress in wheat. Moreover, the mechanisms by which miRNAs confer different levels of dehydration stress tolerance in different wheat genotypes are unclear.ResultsWe examined miRNA expressions in two different wheat genotypes, Hanxuan10, which is drought-tolerant, and Zhengyin1, which is drought-susceptible. Using a deep-sequencing method, we identified 367 differentially expressed miRNAs (including 46 conserved miRNAs and 321 novel miRNAs) and compared their expression levels in the two genotypes. Among them, 233 miRNAs were upregulated and 10 were downregulated in both wheat genotypes after dehydration stress. Interestingly, 13 miRNAs exhibited opposite patterns of expression in the two wheat genotypes, downregulation in the drought-tolerant cultivar and upregulation in the drought-susceptible cultivar. We also identified 111 miRNAs that were expressed predominantly in only one or the other genotype after dehydration stress. We verified the expression patterns of a number of representative miRNAs using qPCR analysis and northern blot, which produced results consistent with those of the deep-sequencing method. Moreover, monitoring the expression levels of 10 target genes by qPCR analysis revealed negative correlations with the levels of their corresponding miRNAs.ConclusionsThese results indicate that differentially expressed patterns of miRNAs between these two genotypes may play important roles in dehydration stress tolerance in wheat and may be a key factor in determining the levels of stress tolerance in different wheat genotypes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0413-9) contains supplementary material, which is available to authorized users.

Highlights

MicroRNAs play critical roles in the processes of plant growth and development, but little is known of their functions during dehydration stress in wheat
The chlorophyll content of the Hanxuan plants (T1) and T2 decreased by 12.87% and 16.73% than that of C1 and C2, and relative water content of T1 and T2 decreased by 4.70% and 10.58% after dehydration stress, respectively (Additional file 1: Table S1)
Numbers of lateral roots of T2 decreased by 0.8 than C2 after 12h dehydration stress, but T1 only decreased by 0.2 than C1 (Table 1). These results suggested that dehydration stress significantly inhibited lateral roots growth and development of the droughtsusceptible cultivar, but had a lesser effect on the drought-tolerant cultivar

Summary

Introduction

MicroRNAs (miRNAs) play critical roles in the processes of plant growth and development, but little is known of their functions during dehydration stress in wheat. The mechanisms by which miRNAs confer different levels of dehydration stress tolerance in different wheat genotypes are unclear. As non-protein-coding gene products, microRNAs (miRNAs), ranging in length from 18 to 25 nucleotides, regulate gene expression either through post-transcriptional degradation or translational repression of their target mRNAs. In plants, most miRNAs have perfect or near-. MiRNAs play critical roles in plant resistance to various abiotic and biotic stresses [9,10,11]. MiR167 play roles in regulating the auxinsignaling pathway and possibly in the developmental response to cold stress [12]. MiR827 and miR2005 are up-regulated in wheat both under powdery mildew infection and heat stress, whereas miR156, miR159, miR168, miR393, miR2001, and miR2013 exhibit opposite expression pattern response to these stresses [14]

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Conclusion