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                孟祥宗课题组揭示拟南芥中植保素合成调控机制

                发布者:新闻中心作者:发布时间:2020-05-22浏览次数:406


                 

                植保素是植物在被病原菌侵染后诱导合成的、具抗菌功能的◢一类低分子量次生代谢物,不同科的植物往往合成不同种类的植保素 (Piasecka et al., 2015),在╳植物抗病过程中发挥重要作用。Camalexin (即3-thiazol-2’-yl-indole) 是十字花科植物特有的植保素,又被称为亚麻荠素,它是一种含硫的吲哚生物碱,也是模式植物拟南芥中最主要的植保素。健康拟南芥植物中camalexin的含量很低,细菌、真菌、卵菌等营养型或腐生型病原菌的侵染几乎都能↘诱导拟南芥合成camalexin。Camalexin在拟南芥抵抗这些病原菌入侵过程中发挥重要作用 (Piasecka et al., 2015)。  

                近日,我校生命科学学院︻孟祥宗课题△组在The Plant Cell上发表了一篇题为←Differential Phosphorylation of the Transcription Factor WRKY33 by the Protein Kinases CPK5/CPK6 and MPK3/MPK6 Cooperatively Regulates Camalexin Biosynthesis in Arabidopsis的研究论文。本研究发现拟南芥钙依赖蛋白激酶CPK5、CPK6和丝裂原活化蛋白激→酶MPK3、MPK6协同调控病原菌诱导的植保素camalexin合成,进而鉴定到』转录因子WRKY33作用于CPK5/CPK6和MPK3/MPK6下游调控camalexin合成 (Zhou et al., 2020)。进一步的生化实验证明WRKY33是CPK5/CPK6和MPK3/MPK6的公共底物蛋白,CPK5/CPK6通过︾磷酸化WRKY33蛋白中的Thr-229位点而增强WRKY33的DNA结合活性,MPK3/MPK6则通过磷酸化WRKY33蛋白N端的多个Ser位点而激活WRKY33的转录激活活Ψ 性,继而活化的WRKY33直接激活camalexin合成基因的表达并最△终诱导camalexin合成 (图1) (Zhou et al., 2020)。因此,该研究发现了拟南芥中钙依赖蛋白激酶CPK5、CPK6和丝裂原活〓化蛋白激酶MPK3、MPK6通过磷酸化它们下游的公共底物转录因子WRKY33而协同诱导植保素camalexin合成并【增强植物抗病性的分子机制,同时揭示了植物抗病过程中的两类关◇键蛋白激酶(钙依↓赖蛋白激酶和丝裂原活化蛋白激酶)的协同作用机制。  

                据悉,彩神大发app下载周京赓副教〖授为该论文的第一作者,孟祥宗教授为通讯作者。中科院植物逆境中心王鹏程研究员、彩神大发app下载■戴绍军教授和密苏里大学张舒群教授也参与了该研究。该研究得到了国家自然科学基金项①目的资助。  

                另外,植保素等抗病ㄨ次生代谢物在被病原菌诱导合成后往往需要依赖于特定转运蛋白将其运输到病原菌入侵位点,才能有效发挥抗菌功能。值得一提◎的是,孟祥宗课题组还在稍前发表于Plant Cell的另外一个工作中揭示了拟南芥转运蛋白PEN3和PDR12负责介导植保素camalexin的跨膜定向转运,从而将被诱导合成的camalexin快速转运出植物细胞,发挥抗菌效应 (图1) (He et al., 2019)。

                    


                拟南芥中植保素camalexin的合成、转运及其调控机制

                  

                参考文献:

                Piasecka A., Jedrzejczak-Rey N., and Bednarek P. Secondary metabolites in plant innate immunity: conserved function of divergent chemicals. New Phytol (2015), 206: 948-964.

                Zhou J., Wang X., He Y., Sang T., Wang P., Dai S. Zhang S., and Meng X. Differential Phosphorylation of the Transcription Factor WRKY33 by the Protein Kinases CPK5/CPK6 and MPK3/MPK6 Cooperatively Regulates Camalexin Biosynthesis in Arabidopsis. Plant Cell (2020), https://doi.org/10.1105/tpc.19.00971.

                He Y., Xu J., Wang X., He X., Wang Y., Zhou J., Zhang S., and Meng X. The Arabidopsis Pleiotropic Drug Resistance Transporters PEN3 and PDR12 Mediate Camalexin Secretion for Resistance to Botrytis cinerea. Plant Cell (2019), 31: 2206-2222.

                  

                (供稿、图片:生命科学学院)