Rice WRKY4 acts as a transcriptional activator mediating defense responses toward Rhizoctonia solani, the causing agent of rice sheath blight
- 1.3k Downloads
WRKY transcription factors have been implicated in the regulation of transcriptional reprogramming associated with various plant processes but most notably with plant defense responses to pathogens. Here we demonstrate that expression of rice WRKY4 gene (OsWRKY4) was rapidly and strongly induced upon infection of Rhizoctonia solani, the causing agent of rice sheath blight, and exogenous jasmonic acid (JA) and ethylene (ET). OsWRKY4 is localized to the nucleus of plant cells and possesses transcriptional activation ability. Modulation of OsWRKY4 transcript levels by constitutive overexpression increases resistance to the necrotrophic sheath blight fungus, concomitant with elevated expression of JA- and ET-responsive pathogenesis-related (PR) genes such as PR1a, PR1b, PR5 and PR10/PBZ1. Suppression by RNA interference (RNAi), on the other hand, compromises resistance to the fungal pathogen. Yeast one-hybrid assay and transient expression in tobacco cells reveal that OsWRKY4 specifically binds to the promoter regions of PR1b and PR5 which contain W-box (TTGAC[C/T]), or W-box like (TGAC[C/T]) cis-elements. In conclusion, we propose that OsWRKY4 functions as an important positive regulator that is implicated in the defense responses to rice sheath blight via JA/ET-dependent signal pathway.
KeywordsDisease resistance Rhizoctonia solani Transcription factor WRKY protein Oryza sativa
This research was funded by National Natural Science Foundation of China (Grant Nos. 31171803, 31301617) and Project of Hunan Provincial Natural Science Foundation of China (Grant No. 10JJ2030).
Compliance with ethical standards
Conflict of interest
All authors have read and approved this version of the article, and due care has been taken to ensure the integrity of the work. The authors declare that there are no potential conflicts of interest regarding the publication of this paper.
- Alexander D, Goodman RM, Gut-Rella M, Glascock C, Weymann K, Friedrich L, Maddox D, Ahl-Goy P, Luntz T, War E, Ryals J (1993) Increased tolerance to 2 oomycete pathogens in transgenic tobacco expressing pathogenesis-related protein 1a. Proc Natl Acad Sci USA 90:7327–7331PubMedCentralCrossRefPubMedGoogle Scholar
- Chujo T, Miyamoto K, Shimogawa T, Shimizu T, Otake Y, Yokotani N, Nishizawa Y, Shibuya N, Nojiri H, Yamane H, Minami E, Okada K (2013) OsWRKY28, a PAMP-responsive transrepressor, negatively regulates innate immune responses in rice against rice blast fungus. Plant Mol Biol 82:23–37CrossRefPubMedGoogle Scholar
- Datta K, Velazhahan R, Oliva N, Ona I, Mew T, Khush GS, Muthukrishnan S, Datta SK (1999) Over-expression of the cloned rice thaumatin-like protein (PR-5) gene in transgenic rice plants enhances environmental friendly resistance to Rhizoctonia solani causing sheath blight disease. Theor Appl Genet 98:1138–1145CrossRefGoogle Scholar
- Niederman T, Genetet I, Bruyere T, Gees R, Stinzi A, Legrand M, Fritig B, Mosinger E (1995) Pathogenesis-related PR-1 proteins are antifungal: isolation and characterization of three 14 kidodalton proteins of tomato and of a basic PR-1 of tobacco with inhibitory activity against Phytophythora infestans. Plant Physiol 108:17–27CrossRefGoogle Scholar
- Rush MC, Hoff BJ, Mcllrath WO (1976) A uniform disease rating system for rice disease in the United States. In: Proceedings of the 16th Rice Technical Working Group, Lake Charles, Louisiana, USA, 64Google Scholar
- Sambrook J, Fritsch EF, Maniatis T (1989) Molecular cloning. A laboratory manual, 2nd edn. Cold Spring Harbor Laboratory Press, New YorkGoogle Scholar
- Thomma BPHJ, Eggermont K, Penninckx IAMA, Mauch-Mani B, Vogelsang R, Cammue BPA, Broekaert WF (1998) Separate jasmonate-dependent and salicylate-dependent defense-response pathways in Arabidopsis are essential for resistance to distinct microbial pathogens. Proc Natl Acad Sci USA 95:15107–15111PubMedCentralCrossRefPubMedGoogle Scholar
- Turner JG, Ellis C, Devoto A (2012) The jasmonate signal pathway. Plant Cell 14:S153–S164Google Scholar
- Wang ZB, Zuo SM, Li G, Chen XJ, Chen ZX, Zhang YF, Pan XB (2009) Rapid identification technology of resistance to rice sheath blight in seedling stage. Acta Phytopathol Sin 39:174–182Google Scholar
- Wang Y, Dang F, Liu Z, Wang X, Eulgem T, Lai Y, Yu L, She J, Shi Y, Lin J, Chen C, Guan D, Qiu A, He S (2013) CaWRKY58, encoding a group I WRKY transcription factor of Capsicum annuum, negatively regulates resistance to Ralstonia solanacearum infection. Mol Plant Pathol 14:131–144CrossRefPubMedGoogle Scholar
- Yokotani N, Sato Y, Tanabe S, Chujo T, Shimizu T, Okada K, Yamane H, Shimono M, Sugano S, Takatsuji H, Kaku H, Minami E, Nishizawa Y (2013) WRKY76 is a rice transcriptional repressor playing opposite roles in blast disease resistance and cold stress tolerance. J Exp Bot 64:5085–5097PubMedCentralCrossRefPubMedGoogle Scholar
- Zhao CJ, Lu GD, Du XY, Liu L, Lin Y, Shi YJ, Wang ZH (2006) PR1 and PBZ1 expression through the infection progress of rice sheath blight. Acta Phytopathol Sin 36:317–321Google Scholar