西农郭军团队利用HIGS技术增强小麦条锈病抗性

由条型柄锈菌引起的条锈病是小麦上的一种重大病害，严重危害小麦生产。由于小麦条锈菌频繁变异，常常导致小麦品种抗病性不断“丧失”，引致病害流行成灾。HIGS技术近年来在研究宿主和真菌的互作模式以及创造新型抗病作物方面得到了广泛的应用。近日西北农林科技大学植物保护学院郭军教授课题组就利用HIGS技术增强了小麦对条锈病的抗性。

蛋白激酶A（Protein kinase A, PKA）在病原真菌的致病过程中起着重要的调节作用。来自条锈菌的PsCPK1基因能催化PKA亚基并且在条锈菌侵染的早期诱导表达。研究人员利用大麦条纹花叶病毒BSMV（barley stripe mosaic virus）介导的宿主诱导基因沉默（host-induced gene silencing, HIGS）技术瞬时沉默PsCPK1能够减少浸染的菌丝长度和抗性表型。转基因小麦表型鉴定结果也表明了其对条锈菌的稳定持久的高抗效果。
该研究提供了对抗作物条锈病的新途径。
Plant Biotechnol J. 2017 Sep 7.
Host-induced gene silencing of an important pathogenicity factor PsCPK1 in Puccinia striiformis f. sp. tritici enhances resistance of wheat to stripe rust.
Author
Qi T, Zhu X, Tan C, Liu P, Guo J, Kang Z, Guo J.
State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, China.
Abstract
Rust fungi are devastating plant pathogens and cause a large economic impact on wheat production worldwide. To overcome this rapidly loss of varieties resistance, we generated stable transgenic wheat plants expressing short interfering RNAs (siRNAs) targeting potentially vital genes of Puccinia striiformis f. sp. tritici (Pst). Protein kinase A (PKA) has been proved to play important roles in regulating the virulence of phytopathogenic fungi. PsCPK1, a PKA catalytic subunit gene from Pst, is highly induced at the early infection stage of Pst. The instantaneous silencing of PsCPK1 by barley stripe mosaic virus (BSMV)-mediated host-induced gene silencing (HIGS) results in a significant reduction in the length of infection hyphae and disease phenotype. These results indicate that PsCPK1 is an important pathogenicity factor by regulating Pst growth and development. Two transgenic lines expressing the RNA interference (RNAi) construct in a normally susceptible wheat cultivar displayed high levels of stable and consistent resistance to Pst throughout the T3 to T4 generations. The presence of the interfering RNAs in transgenic wheat plants was confirmed by northern blotting, and these RNAs were found to efficiently down-regulate PsCPK1 expression in wheat. The present study addresses important aspects for the development of fungal-derived resistance through the expression of silencing constructs in host plants as a powerful strategy to control cereal rust diseases.

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