TaGAD在小麦抵抗叶锈菌侵染中的作用

Role of TaGAD in leaf rust resistance in wheat

本研究以小麦近等基因系TcLr26及其轮回亲本Thatcher(Tc)分别与叶锈菌生理小种260组成不亲和组合及亲和组合,利用RT-qPCR技术检测发现TaGAD的表达在不亲和组合接种后早期(4,8,12h)没有明显变化,从接种后16～72h伴随着HR的发生被诱导表达;而在亲和组合中TaGAD只在接种后8～12h表达有所增加;利用瞬时转化烟草,发现TaGAD定位于细胞质;利用RNAi技术沉默TaGAD基因后,与对照相比单侵染点寄主HR面积明显减少。研究结果表明,TaGAD在小麦抵抗叶锈菌侵染的HR发生中发挥着重要作用。

Puccinia triticina is a highly specialized living nutritive fungi.The hypersensitive reaction(HR)is an important defense reaction against Puccinia triticina in wheat.γ-aminobutyric acid(GABA)is a four-carbon non-protein amino acid,GABA plays an important role in plant growth,development and stress adaptation.In the previous work,we analyzed the transcription data of wheat and Puccinia triticina interactions and screened the significantly different expression of TaGAD,which is a key gene in the GABA shunt,in the incompatible and compatible interaction.Based on this,RT-qPCR technique was used to detect the expression characteristics of TaGAD at different times after inoculation.The result showed that the expression of TaGAD did not obviously change at 4,8 and 12 h after inoculation,and was induced from 16 to 72 h after inoculation with the development of HR in the incompatible interaction;whereas in the compatible interaction,the expression of TaGAD was only increased at 8-12h after inoculation.Transient transformation of tobacco revealed that TaGAD was localized in the cytoplasm.After silencing the TaGAD gene by RNAi,the HR area of the host at the single infection site was significantly reduced compared with the control.In summary,TaGAD plays an important role in the occurrence of HR against Puccinia triticina infection in wheat.