泛素受体蛋白OsDSK2b负向调控水稻叶瘟和渗透胁迫抗性  

Ubiquitin receptor protein OsDSK2b plays a negative role in rice leaf blast resistance and osmotic stress tolerance

作　　者：丁杰荣 马雅美 潘发枝 江立群 黄文洁 孙炳蕊[1] 张静 吕树伟 毛兴学[1] 于航 李晨[1] 刘清[1] DING Jie-Rong;MA Ya-Mei;PAN Fa-Zhi;JIANG Li-Qun;HUANG Wen-Jie;SUN Bing-Rui;ZHANG Jing;LYU Shu-Wei;MAO Xing-Xue;YU Hang;LI Chen;LIU Qing(Rice Research Institute,Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory,Guangzhou 510640,Guangdong,China;South China Agricultural University,Guangzhou 510642,Guangdong,China;Agro-biological Gene Research Center,Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory for Crop Germplasm Resources Preservation and Utilization,Guangzhou 510640,Guangdong,China)

机构地区：[1]广东省农业科学院水稻研究所/广东省水稻育种新技术重点实验室/广东省水稻工程实验室,广东广州510640 [2]华南农业大学,广东广州510642 [3]广东省农业科学院农业生物基因研究中心/广东省农作物种质资源保护与利用重点实验室,广东广州510640

出　　处：《作物学报》2023年第6期1466-1479,共14页Acta Agronomica Sinica

基　　金：广东省发展和改革委、农业农村厅投资项目(粤发改农经[2021]272号);科技创新战略专项资金:广东省农业科学院高水平人才建设项目(R2020PY-JX001);广东省重点实验室运行费专项(2020B1212060047)资助

摘　　要：泛素受体蛋白DSK2(dominant suppressor of KAR2)在植物生长发育和逆境胁迫中发挥重要作用,但其在水稻抗病和渗透胁迫中的作用尚未见报道。本研究发现OsDSK2b受多种逆境的调控,该基因的表达水平在稻瘟病菌侵染和20%PEG-6000处理后显著降低。时空表达分析表明OsDSK2b基因在三叶期幼苗中的表达水平最高,亚细胞定位结果显示该蛋白定位于细胞质。接种稻瘟病菌(GD08-T13和Guy11)后,敲除植株的病斑面积约为0.05 cm^(2)和0.10~0.13 cm^(2),远小于野生型植株的病斑面积(0.24 cm^(2)和0.31 cm^(2))。敲除OsDSK2b显著增强水稻的叶瘟抗性。而且在病原菌侵染后,敲除植株中病程相关蛋白(PR)基因的表达受到明显诱导。敲除OsDSK2b也显著增强水稻的渗透胁迫抗性,20%PEG-6000模拟渗透胁迫处理后,OsDSK2b敲除植株的存活率为58.3%~74.0%,显著高于野生型植株的存活率(17.0%)。OsDSK2b敲除植株的离子渗透率和植株失水率则显著低于野生型植株。扫描显微镜的结果表明,无论在20%PEG-6000处理前后,敲除OsDSK2b能够促进气孔的闭合,且在20%PEG-6000处理后,这种促进作用会更强。此外,qRT-PCR结果表明,在20%PEG-6000处理后,OsDSK2b敲除植株中DREB基因以及脱落酸(ABA)合成或通路相关基因的表达水平显著高于野生型植株,且敲除植株ko6和ko14的内源ABA含量分别为314.2 ng g^(-1)和344.4 ng g^(-1),显著高于野生型植株的内源ABA含量(206.8 ng g^(-1)),揭示OsDSK2b参与调控渗透胁迫的过程同时涉及ABA依赖和ABA非依赖途径。本研究通过解析OsDSK2b基因在水稻应对生物与非生物胁迫时所发挥的调控作用,为水稻抗性品种的选育提供了新的候选基因。The ubiquitin receptor protein DSK2(dominant suppressor of KAR2)plays an important role in the growth,development,and stress tolerance in plant,but its role in rice disease resistance and osmotic stress has not been reported yet.In this study,we identified that OsDSK2b was regulated by various stresses,and the relative expression level of this gene decreased significantly after Magnaporthe oryzae infection and 20%PEG-6000 treatment.The spatio-temporal expression analysis showed that the relative expression level of OsDSK2b was highest at three-leaf seedling stage.The subcellular localization analysis demonstrated that OsDSK2b was localized in the cytoplasm in rice protoplast.The lesion area of OsDSK2b knockout plants was about 0.05 cm^(2)and 0.10-0.13 cm^(2),which was much smaller than wild-type plants(0.24 cm^(2)and 0.31 cm^(2))after inoculation with Magnaporthe oryzae(GD08-T13 and Guy11).Compared with wild-type plants,knockout of OsDSK2b significantly enhanced the leaf blast resistance in rice,and the relative expression levels of pathogenesis-related protein(PR)genes were induced significantly in OsDSK2b knockout plants after Magnaporthe oryzae(Guy11)infection.The knockout of OsDSK2b also significantly enhanced the osmotic stress tolerance in rice.OsDSK2b knockout plants had higher survival rate(58.3%-74.0%)than wild-type plants(17.0%)after 20%PEG-6000 treatment.Meanwhile,compared with wild-type plants,OsDSK2b knockout plants had lower ion permeability and water loss rate after 20%PEG-6000 treatment.Scanning microscopy revealed that knockout of OsDSK2b could promote the stomatal closure both before and after 20%PEG-6000 treatment,and the promotion effect was stronger after osmotic stress treatment.In addition,qRT-PCR results showed that the relative expression level of DREB genes and abscisic acid(ABA)synthesis or pathway-related genes were significantly higher in OsDSK2b knockout plants than wild-type plants after osmotic stress treatment.The endogenous ABA contents of ko6 and ko14 knockout plants were 314.2

关 键 词：水稻(Oryza sativa L.) 稻瘟病 渗透胁迫 PR DREB ABA 

分 类 号：S511[农业科学—作物学]