蛋白激酶SAPK2响应水稻缺钾胁迫的机制研究

Mechanism of Protein Kinase SAPK2 in Response to Potassium Deficiency Stress in Rice

在缺K条件下,利用CRISPR/Cas9(Clustered regularly interspaced short palindromic repeats/Cas9)技术构建好的sapk2(Osmotic stress/ABA-activated protein kinase 2)突变体和野生型水稻(Oryza sativa)种子研究SAPK2基因表达模式、水稻材料的萌发及苗期生长情况、K+代谢相关基因的表达水平,以揭示SAPK2蛋白参与水稻响应缺K胁迫的机制。结果表明,缺N、P、K处理导致水稻中SAPK2表达量显著下降;与野生型相比,sapk2突变体在缺K环境下萌发明显延迟,萌发率降低,sapk2突变体在缺K环境下苗期生长受到严重的抑制;与野生型相比,sapk2突变体OsKAT1(Potassium channel gene 1)、OsKAT2、OsAKT1(Shaker K+channel 1)和OsHAK1(High-affinity K+transporter 1)等K+代谢相关基因的表达水平显著下调。说明SAPK2在缺K环境下水稻种子萌发和苗期营养生长过程中发挥重要的正调节作用,其机制可能是通过直接或者间接调节K+代谢相关基因的表达水平来参与缺K胁迫响应。

In order to reveal the function and mechanism of SAPK2(osmotic stress/ABA-activated protein kinase 2)involved in rice(Oryza sativa L.)response to K deficiency,the sapk2 mutants constructed by CRISPR/Cas9(clustered regularly interspaced short palindromic repeats/Cas9)technology and wild type rice seeds were used to study SAPK2 expression profiles,germination,growth of seedling and the expression levels of K+metabolism-related genes under K deficiency condition.The results showed that the N,P and K deficiency treatments caused a significant decrease in the expression level of SAPK2 in rice;compared with the wild type,the germination of the sapk2 mutants was significantly delayed,the germination rate was significantly reduced,and the seedling growth was severely inhibited under the K deficiency condition;compared with wild-type,the expression levels of K+metabolism-related genes such as OsKAT1(potassium channel gene 1),OsKAT2(potassium channel gene 2),OsAKT1(shaker K+channel 1)and OsHAK1(high-affinity potassium transporter 1)in sapk2 mutants were significantly downregulated.These results indicated that SAPK2 played an important positive regulatory role in the process of seed germination and seedling vegetative growth of rice under K deficiency environment,and the mechanism may be that SAPK2 directly or indirectly regulated the expression level of K+metabolismrelated genes to participate in the K deficiency response.