Inhibition of multiple defense responsive pathways by CaWRKY70 transcription factor promotes susceptibility in chickpea under Fusarium oxysporum stress condition
Inhibition of multiple defense responsive pathways by CaWRKY70 transcription factor promotes susceptibility in chickpea under Fusarium oxysporum stress condition
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DOI：
10.1186/s12870-020-02527-9
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发表时间：
2020-07-06
影响因子：
5.3
通讯作者：
Das, Sampa
中科院分区：
文献类型：
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作者：
Chakraborty, Joydeep;Sen, Senjuti;Das, Sampa
背景植物防御基因的抑制和激活受WRKY家族转录因子的全面调控。鹰嘴豆是一种非模式作物豆科牧草，由尖孢镰刀菌引起的枯萎病。Ciceri Race1(Foc1)，其防御反应机制尚不清楚。结果在本研究中，我们发现WRKY70(CaWRKY70)负调控多条防御反应通路，其中包括系统获得性抗性(SAR)的激活。在Foc1胁迫和水杨酸(SA)处理下，CaWRKY70在感病鹰嘴豆(JG62)地上部组织中显著积累。CaWRKY70的过表达促进了抗性鹰嘴豆(WR315)植株对Foc1侵染的敏感性。转基因植株接种Foc1不仅抑制了内源SA浓度，而且抑制了SA信号转导相关基因的表达。与对照(VC)相比，高表达CaWRKY70的鹰嘴豆根具有更高的离子渗漏和Foc1生物量积累。在感染Foc1的鹰嘴豆根、茎和叶中，CaWRKY70的过表达抑制了过氧化氢的产生和产生的活性氧(ROS)诱导的细胞死亡。作为核靶向蛋白，CaWRKY70通过其直接和间接的负调控作用抑制鹰嘴豆中的CaMPK9-CaWRKY40信号转导。蛋白质-蛋白质相互作用研究表明，CaWRKY70和类CaRPP2 CC-NB-ARC-LRR蛋白抑制鹰嘴豆的超免疫信号转导。本研究对CaWRKY70抑制Foc1胁迫下鹰嘴豆多种防御信号成分的机制提供了新的见解。结论CaWRKY70介导的防御抑制揭示了Foc1胁迫下影响鹰嘴豆下游抗性机制的几个免疫信号事件之间的网络联系。
BackgroundSuppression and activation of plant defense genes is comprehensively regulated by WRKY family transcription factors. Chickpea, the non-model crop legume suffers from wilt caused by Fusarium oxysporum f. sp. ciceri Race1 (Foc1), defense response mechanisms of which are poorly understood. Here, we attempted to show interaction between WRKY70 and several downstream signaling components involved in susceptibility/resistance response in chickpea upon challenge with Foc1.ResultsIn the present study, we found Cicer arietinum L. WRKY70 (CaWRKY70) negatively governs multiple defense responsive pathways, including Systemic Acquired Resistance (SAR) activation in chickpea upon Foc1 infection. CaWRKY70 is found to be significantly accumulated at shoot tissues of susceptible (JG62) chickpea under Foc1 stress and salicylic acid (SA) application. CaWRKY70 overexpression promotes susceptibility in resistant chickpea (WR315) plants to Foc1 infection. Transgenic plants upon Foc1 inoculation demonstrated suppression of not only endogenous SA concentrations but expression of genes involved in SA signaling. CaWRKY70 overexpressing chickpea roots exhibited higher ion-leakage and Foc1 biomass accumulation compared to control transgenic (VC) plants. CaWRKY70 overexpression suppresses H2O2 production and resultant reactive oxygen species (ROS) induced cell death in Foc1 infected chickpea roots, stem and leaves. Being the nuclear targeted protein, CaWRKY70 suppresses CaMPK9-CaWRKY40 signaling in chickpea through its direct and indirect negative regulatory activities. Protein-protein interaction study revealed CaWRKY70 and CaRPP2-like CC-NB-ARC-LRR protein suppresses hyper-immune signaling in chickpea. Together, our study provides novel insights into mechanisms of suppression of the multiple defense signaling components in chickpea by CaWRKY70 under Foc1 stress.ConclusionCaWRKY70 mediated defense suppression unveils networking between several immune signaling events negatively affecting downstream resistance mechanisms in chickpea under Foc1 stress.