Genome-wide identification of long intergenic non-coding RNAs of responsive to powdery mildew stress in wheat (Triticum aestivum).

Wheat powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most serious foliar diseases of wheat, causing grain yield and quality degradation by affecting plant photosynthesis. It is an effective method to improve the disease resistance of wheat plants by molecular breeding. With the continuous development of sequencing technology, long intergenic noncoding RNAs (lincRNAs) have been discovered in many eukaryotes and act as key regulators of many cellular processes. In this study, 12 sets of RNA-seq data from wheat leaves pre- and post-pathogen infection were analyzed and 2,266 candidate lincRNAs were identified. Consistent with previous findings, lincRNA has shorter length and fewer exons than mRNA. The results of differential expression analysis showed that 486 DE-lincRNAs were selected as lincRNAs that could respond to powdery mildew stress. Since lincRNAs may be functionally related to their adjacent target genes, the target genes of these lincRNAs were predicted, and the GO and KEGG functional annotations of the predicted target genes were performed. Integrating the functions of target genes and the biological processes in which they were involved uncovered 23 lincRNAs that may promote or inhibit the occurrence of wheat powdery mildew. Co-expression patterns of lincRNAs with their adjacent mRNAs showed that some lincRNAs showed significant correlation with the expression patterns of their potential target genes. These suggested an involvement of lincRNAs in pathogen stress response, which will provide a further understanding of the pathogenic mechanism of wheat powdery mildew.

Genome-wide characterization and function analysis uncovered roles of wheat LIMs in responding to adverse stresses and TaLIM8-4D function as a susceptible gene.

The Lin-11, Isl-1, and Mec-3 domains (LIM) transcription factors play essential roles in regulating plant biological processes. Despite that, there is a lack of a full understanding of LIMs in wheat (Triticum aestivum L.). In this study, 28 wheat LIM s (TaLIMs) were identified and designated as TaLIM1-1A to TaLIM12-7D. The cis-regulatory element analysis showed that TaLIMs were rich in elements related to biological and abiotic stresses. Expression profiling analysis showed that certain members of TaLIMs were responsive to biotic and abiotic stresses, such as TaLIM1-1A, TaLIM3-2B, TaLIM8-4D, and TaLIM10-5D, were significantly induced by heat, drought, sodium chloride (NaCl), abscisic acid (ABA) and Fusarium graminearum stresses. Furthermore, the biological function of TaLIM8-4D was analyzed and results showed that it was subcellular localization in the nucleus and could induce weak cell death in Nicotiana benthamiana leaves. Additionally, overexpression of TaLIM8-4D could upregulate plant pathogenesis-related (PR) genes, promoting the infection of hemibiotrophic pathogen, implying that TaLIM8-4D could function as susceptible gene in the nucleus by upregulating PR genes and inducing cell death to promote the colonization of hemibiotrophic agent F. graminearum. Overall, the systematic identification, characterization, expression profiling, evolutionary, and function analyses provided the ability to understand TaLIMs and laid a foundation for the further function study of LIM family members in wheat.