小麦与白粉菌互作中TaSTPK-CCR3基因功能的初步研究

Function analysis of TaSTPK-CCR3 gene during compatible interaction between wheat and powdery mildew

为了探究蛋白激酶在小麦与白粉菌互作中的作用,从白粉菌敏感型小麦品种京411中克隆得到1个丝/苏氨酸蛋白激酶基因,命名为TaSTPK-CCR3.该基因包含开放阅读框1644 bp,预测编码547个氨基酸残基.经NCBI/Blastx比对分析,发现TaSTPK-CCR3包含蛋白激酶超家族类似催化结构域(PKclike superfamily),与粗山羊草中预测的STPK-CCR3蛋白激酶(XP020154056.1)具有74.21%的同源性.在感病小麦京411中,该基因表达量在白粉菌侵染2 hpi后迅速下调,4 hpi降至最低,8 hpi出现明显回升,由此推测TaSTPK-CCR3参与小麦对白粉菌胁迫的早期应答反应.利用病毒诱导基因沉默(virus induced gene silencing,VIGS)技术敲减京411中TaSTPK-CCR3基因后,白粉菌孢子的成功侵染率有所下降,且畸形率明显上升.在接种白粉菌7 d后,实验组(BSMV:TaSTPK-CCR3)小麦叶片上的白粉病菌斑明显少于对照组(BSMV:GFP,GKP Buffer对照组),说明该基因表达量的降低在一定程度上改变了京411小麦对白粉菌的敏感程度.上述结果表明,TaSTPK-CCR3基因可能参与小麦-白粉菌互作的早期应答反应.

To explore the function of protein kinase during compatible interaction between wheat and powdery mildew,a serine/threonine protein kinase gene was isolated from the wheat cultivar Jing411 susceptible to Blumeria graminis f.sp. Tritici(Bgt,the causal agent of wheat powdery mildew),designated Ta STPK-CCR3. The open reading frame of TaSTPK-CCR3 was1 644 bp,encoding a predicted protein of 547 amino acids. The protein alignment by NCBI/Blastx showed that the predicted protein sequence was 74.21% similar with the orthologs in Aegilops tauschii subsp.tauschii(XP020154056.1),which belongs to PKclike super-family. In the susceptible cultivar wheat Jing411,the expression level of TaSTPK-CCR3 decreased rapidly at2 hpi and reached the minimum at 4 hpi. Then the expression level increased significantly at 8 hpi. These results suggest that TaSTPK-CCR3 may be involved in the early response to powdery mildew. Virus induced gene silencing system(VIGS)was used to knockdown the TaSTPK-CCR3 in Jing411. Statistical analyses showed that the successful penetration rate of Bgt decreased,while the percentage of macrocephalic appressoria increased significantly. In BSMV:TaSTPK-CCR3 silenced Jing411 leaves,Bgt developed slowly at 7 dpi. However,after the inoculation of Jing411 leaves with BSMV:GFP(GKP Buffer)and Bgt at7 dpi,Bgt was observed to develop quickly on Jing411 leaves,and more hyphae and conidiophores were observed on the leaf surface,which suggested that TaSTPK-CCR3-silencing improve resistance to Bgt in Jing411. These findings indicate that TaSTPK-CCR3 gene could be involved in the early defense response against wheat powdery mildew and may play an important role in wheat-Bgt interactions.