Overexpression of CaWRKY27, a subgroup IIe WRKY transcription factor of Capsicum annuum, positively regulates tobacco resistance to Ralstonia solanacearum infection. Issue 3 (16th October 2013)

• Record Type: Journal Article
• Authors: Dang, Fengfeng; Wang, Yuna; She, Jianju; Lei, Yufen; Liu, Zhiqin; Eulgem, Thomas; Lai, Yan; Lin, Jing; Yu, Lu; Lei, Dan; Guan, Deyi; Li, Xia; Yuan, Qian; He, Shuilin
• Is Part Of: Physiologia plantarum. Volume 150:Issue 3(2014:Mar.)
• Page Start: 397
• Page End: 411
• Publication Date: 2013-10-16
• Subjects: Plant physiology -- Periodicals; 571.2
• DOI: 10.1111/ppl.12093
• Languages: English
• ISSNs: 0031-9317

Abstract

<abstract abstract-type="main" id="ppl12093-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p id="ppl12093-para-0001">WRKY proteins are encoded by a large gene family and are linked to many biological processes across a range of plant species. The functions and underlying mechanisms of WRKY proteins have been investigated primarily in model plants such as <italic>Arabidopsis</italic> and rice. The roles of these transcription factors in non‐model plants, including pepper and other Solanaceae, are poorly understood. Here, we characterize the expression and function of a subgroup IIe WRKY protein from pepper (<italic>Capsicum annuum</italic>), denoted as CaWRKY27. The protein localized to nuclei and activated the transcription of a reporter <italic>GUS</italic> gene construct driven by the <italic>35S</italic> promoter that contained two copies of the W‐box in its proximal upstream region. Inoculation of pepper cultivars with <italic>Ralstonia solanacearum</italic> induced the expression of <italic>CaWRKY27</italic> transcript in 76a, a bacterial wilt‐resistant pepper cultivar, whereas it downregulated the expression of <italic>CaWRKY27</italic> transcript in Gui‐1‐3, a bacterial wilt‐susceptible pepper cultivar. <italic>CaWRKY27</italic> transcript levels were also increased by treatments with salicylic acid (SA), methyl jasmonate (MeJA) and ethephon (ETH). Transgenic tobacco plants overexpressing <italic>CaWRKY27</italic> exhibited resistance to <italic>R. solanacearum</italic> infection compared to that of wild‐type plants. This resistance was coupled with increased transcript levels in a number of marker genes, including hypersensitive response genes, and SA‐, JA‐ and ET‐associated genes. By contrast, virus‐induced gene silencing (VIGS) of <italic>CaWRKY27</italic> increased the susceptibility of pepper plants to <italic>R. solanacearum</italic> infection. These results suggest that <italic>CaWRKY27</italic> acts as a positive regulator in tobacco resistance responses to <italic>R. solanacearum</italic> infection through modulation of SA‐, JA‐ and ET‐mediated signaling pathways.</p> </abstract>