Identification of microRNAs and their corresponding targets involved in the susceptibility interaction of wheat response to Puccinia striiformis f. sp. Tritici.
Hao Feng, Ting Wang, Chuanxin Feng , Qiong Zhang, Xinmei Zhang, Lili Huang, Xiaojie Wang,ZhenshengKang.
Abstract: MicroRNAs (miRNAs) play very important roles in plant defense responses. However, little is known about their roles in the susceptibility interaction between wheat and Puccinia striiformis f. sp. tritici ( Pst ). In this study, two miRNA libraries were constructed from the leaves of the cultivar Xingzi 9104 inoculated with the virulent Pst race CYR32 and sterile water, respectively. A total of 1316 miRNA candidates, including 173 known miRNAs that were generated from 98 pre-miRNAs, were obtained. The remaining 1143 miRNA candidates included 145 conserved and 998 wheat-specific miRNAs that were generated from 87 and 1088 pre-miRNAs, respectively. The 173 known and 145 conserved miRNAs were sub-classified into 63 miRNA families. The target genes of wheat miRNAs were also confirmed using degradome sequencing technology. Most of the annotated target genes were related to signal transduction or energy metabolism. Additionally, we found that miRNAs and their target genes form complicated regulation networks. The expression profiles of miRNAs and their corresponding target genes were further analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), and the results indicate that some miRNAs are involved in the compatible wheat- Pst susceptibility interaction. Importantly, tae-miR1432 was highly expressed when wheat was challenged with CYR32, and the corresponding target gene, predicted to be a calcium ion-binding protein, also exhibited upregulated expression but a divergent expression trend. PC-3P-7484, a specific wheat miRNA, was highly expressed in the wheat response to Pst infection, while the expression of the corresponding target gene ubiquillin was dramatically downregulated. These data provide the foundation for evaluating the important regulatory roles of miRNAs in wheat- Pst susceptibility interaction.