Overexpression of AtWRKY28 and AtWRKY75 in Arabidopsis enhances resistance to oxalic acid and Sclerotinia sclerotiorum

Abstract

Based on Arabidopsis microarray, we found 8 WRKY genes were up-regulated with Oxalic acid (OA) challenge, AtWRKY28 and AtWRKY75 overexpression lines showed enhanced resistance to OA and Sclerotinia sclerotiorum. The WRKY transcription factors are involved in various plant physiological processes and most remarkably in coping with diverse biotic and abiotic stresses. Oxalic acid (OA) is an important pathogenicity-determinant of necrotrophic phytopathogenic fungi, such as Sclerotina sclerotiorum (S. sclerotiorum) and Botrytis cinerea (B. cinerea). The identification of differentially expressed genes under OA stress should facilitate our understanding of the pathogenesis mechanism of OA-producing fungi in host plants, and the mechanism of how plants respond to OA and pathogen infection. Based on Arabidopsis oligo microarray, we found 8 WRKY genes that were up-regulated upon OA challenge. The Arabidopsis plants overexpressing AtWRKY28 and AtWRK75 showed enhanced resistance to OA and S. sclerotiorum simultaneously. Furthermore, our results showed that overexpression of AtWRKY28 and AtWRK75 induced oxidative burst in host plants, which suppressed the hyphal growth of S. sclerotiorum, and consequently inhibited fungal infection. Gene expression profiling indicates that both AtWRKY28 and AtWRKY75 are transcriptional regulators of salicylic acid (SA)- and jasmonic acid/ethylene (JA/ET)-dependent defense signaling pathways, AtWRKY28 and AtWRKY75 mainly active JA/ET pathway to defend Arabidopsis against S. sclerotiorum and oxalic acid stress.

Arabidopsis MYC Transcription Factors Are the Target of Hormonal Salicylic Acid/Jasmonic Acid Cross Talk in Response to Pieris brassicae Egg Extract

“…Since woundactivation of VSP2 was strongly diminished in wrky75-25 and maintained after egg extract treatment in 35S: WRKY75, our results are consistent with a positive role of WRKY75 in the control of the JA-regulated genes independently of MYC2. WRKY75 was previously shown to play a role in plant defense against biotrophs and necrotrophs (Encinas- Villarejo et al, 2009;Windram et al, 2012;Chen et al, 2013). Noteworthy, WRKY75 overexpression was accompanied by elevated expression of JA-responsive genes, including PDF1.2, VSP1, and LOX2, and enhanced resistance against the necrotroph Sclerotinia sclerotiorum .…”

Transcriptomic and metabolomic analyses of cucumber fruit peels reveal a developmental increase in terpenoid glycosides associated with age-related resistance to Phytophthora capsici

“…43 Furthermore, overexpression of WRKY28 , in Arabidopsis led to increased resistance to the necrotrophic pathogen, Sclerotinia sclerotiorum . 44 Thus, increased expression of these genes in resistant ‘Vlaspik’ 16 dpp peels could function as a developmentally regulated mechanism in ARR to P. capsici .…”

Identification of predominant genes involved in regulation and execution of senescence-associated nitrogen remobilization in flag leaves of field grown barley

“…Interestingly, the HvWRKY12 gene was not upregulated during senescence induced by carbohydrate accumulation as a result of steam girdling (Parrot et al , 2007). AtWRKY75 , its orthologous gene in Arabidopsis (Mangelsen et al , 2008), was reported to be upregulated during senescence (Guo et al , 2004b) and in response to pathogens (Chen et al , 2013). OsWRKY72 , its orthologous gene in rice, could be induced by treatment with ABA (Xie et al , 2005).…”