The Elongator complex‐associated protein DRL1 plays a positive role in immune responses against necrotrophic fungal pathogens in Arabidopsis

• Published in: Molecular plant pathology Vol. 19; no. 2; pp. 286 - 299
• Main Authors: Wang, Chenggang, Zhang, Xudong, Li, Jian‐Liang, Zhang, Yanping, Mou, Zhonglin
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.02.2018; John Wiley and Sons Inc
• Subjects: Adenosine triphosphate; Amino acids; Arabidopsis; Arabidopsis - immunology; Arabidopsis - metabolism; Arabidopsis - microbiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Bacteria; Botrytis - pathogenicity; Botrytis cinerea; Calcium-binding protein; Calmodulin; Cell cycle; Cyclopentanes - metabolism; Cytotoxicity; Deformation; DNA-directed RNA polymerase; Domains; DRL1; Elongation; Elongator; ethylene; Ethylenes - metabolism; Fungi; Gene expression; Gene Expression Regulation, Plant - genetics; Gene Expression Regulation, Plant - physiology; GTP-Binding Proteins - genetics; GTP-Binding Proteins - metabolism; Guanosine triphosphate; Homology; Immune response; Immune system; Immunity; Jasmonic acid; KTI12 gene; Mutation; Original; Oxylipins - metabolism; Pathogenesis; Pathogens; Phenotypes; Plant immunity; Proteins; Ribonucleic acid; RNA; RNA polymerase; RNA polymerase II; Salicylic acid; Salicylic Acid - metabolism; Seeds; Signal transduction; Toxicity; Toxins; Variance analysis; Yeast; Yeasts; DRL1; Botrytis cinerea; Arabidopsis; Elongator; salicylic acid; ethylene; jasmonic acid
• ISSN: 1464-6722; 1364-3703
• DOI: 10.1111/mpp.12516

Summary DEFORMED ROOT AND LEAVES1 (DRL1) is an Arabidopsis homologue of the yeast TOXIN TARGET4 (TOT4)/KILLER TOXIN‐INSENSITIVE12 (KTI12) protein that is physically associated with the RNA polymerase II‐interacting protein complex named Elongator. Mutations in DRL1 and Elongator lead to similar morphological and molecular phenotypes, suggesting that DRL1 and Elongator may functionally overlap in Arabidopsis. We have shown previously that Elongator plays an important role in both salicylic acid (SA)‐ and jasmonic acid (JA)/ethylene (ET)‐mediated defence responses. Here, we tested whether DRL1 also plays a similar role as Elongator in plant immune responses. Our results show that, although DRL1 partially contributes to SA‐induced cytotoxicity, it does not play a significant role in SA‐mediated expression of PATHOGENESIS‐RELATED genes and resistance to the virulent bacterial pathogen Pseudomonas syringae pv. maculicola ES4326. In contrast, DRL1 is required for JA/ET‐ and necrotrophic fungal pathogen Botrytis cinerea‐induced defence gene expression and for resistance to B. cinerea and Alternaria brassicicola. Furthermore, unlike the TOT4/KTI12 gene which, when overexpressed in yeast, confers zymocin resistance, a phenotype of the tot4/kti12 mutant, overexpression of DRL1 does not change B. cinerea‐induced defence gene expression and resistance to this pathogen. Finally, DRL1 contains an N‐terminal P‐loop and a C‐terminal calmodulin (CaM)‐binding domain and is a CaM‐binding protein. We demonstrate that both the P‐loop and the CaM‐binding domain are essential for the function of DRL1 in B. cinerea‐induced expression of PDF1.2 and ORA59, and in resistance to B. cinerea, suggesting that the function of DRL1 in plant immunity may be regulated by ATP/GTP and CaM binding.