IDENTIFICATION OF DIFFERENTIALLY EXPRESSED GENES, TRANSCRIPTION FACTORS AND PROTEIN KINASES IN Quercus robur L. UNDER INFECTION WITH POWDERY MILDEW
S. A. Vishnyakov, A. V. Tret’yakova, P. A. Zybinskaya, P. A. Krylov
Federal Scientific Centre of Agroecology, Complex Melioration and Protective Afforestation Russian Academy of Sciences, Volgograd, Russian Federation
Keywords: Quercus robur L, RNA-Seq, differential gene expression, transcription factor, protein kinase, powdery mildew
Abstract
Pedunculate oak ( Quercus robur L.) is susceptible to infection by one of the most widespread phytopathogens - ascomycete fungi of the order Erysiphales , the causal agents of oak powdery mildew, which leads to reduced productivity of forest stands of this species. However, the molecular genetic mechanisms underlying resistance of pedunculate oak to powdery mildew remain insufficiently studied. Therefore, the aim of this study was to identify transcription factor and protein kinase genes involved in the development of adaptive responses of pedunculate oak to the powdery mildew pathogen through the analysis of RNA sequencing data. The identification and differential expression analysis of transcription factors and protein kinases were performed using iTAK v2.0.2 and edgeR, respectively. As a result of RNA-seq data analysis, 2,813 significantly differentially expressed genes were identified, including 166 transcription factor genes and 186 protein kinase genes. Under powdery mildew infection, the largest number of differentially expressed transcription factor genes belonged to the MYB (38), AP2/ERF (23), NAC (17), and WRKY (15) families. It was found that, under infection conditions, genes of the WRKY , GARP-G2-like , BES1 , and BBR-BPC families exhibited the highest expression levels compared with the control. In contrast, genes belonging to the C2C2 , bZIP , HB-HD-Zip , C2H2 , SBP , B3 , zf-HD , SRS , OFP , and HB-WOX transcription factor families were downregulated under powdery mildew infection. Analysis of differentially expressed protein kinase genes in infected pedunculate oak trees revealed that the majority belonged to the RLK/Pelle family (167 genes), displaying both up- and downregulation patterns. Other protein kinase families - AGC , NEK, Group-Pl-2 , ULK , and WNK - were predominantly downregulated, CAMK genes were upregulated, whereas STE and TKL families showed bidirectional regulation in response to infection. The identified genes may be considered promising candidates for further functional studies aimed at elucidating their contribution to powdery mildew resistance in pedunculate oak.
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