Novel Variation and Evolution ofAvrPiz-tofMagnaporthe oryzaein Field Isolates

文献类型： 外文期刊

第一作者： Wang, Qun

作者： Wang, Qun;Li, Jinbin;He, Chengxing;Lu, Lin;Li, Chengyun

作者机构：

关键词： Magnaporthe oryzae; pathogenicity; AvrPiz-t; haplotype diversity; Rice-Magnaportheinteraction

期刊名称：FRONTIERS IN GENETICS （ 影响因子：4.599； 五年影响因子：4.888 ）

ISSN：

年卷期： 2020 年 11 卷

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收录情况： SCI

摘要： The product of the avirulence (Avr) gene ofMagnaporthe oryzaecan be detected by the product of the corresponding resistance (R) gene of rice and activates immunity to rice mediated by theRgene. The high degree of variability ofM. oryzaeisolates in pathogenicity makes the control of rice blast difficult. That resistance of theRgene in rice has been lost has been ascribed to the instability of theAvrgene inM. oryzae. Further study on the variation of theAvrgenes inM. oryzefield isolates may yield valuable information on the durable and effective deployment ofRgenes in rice production areas.AvrPiz-tandPiz-tare a pair of valuable genes in the Rice-Magnaporthepathosystem.AvrPiz-tis detectable byPiz-tand determines the effectiveness ofPiz-t. To effectively deploy theRgenePiz-t, the distribution, variation, and evolution of the correspondingAvrgeneAvrPiz-twere found among 312M. oryzaeisolates collected from Yunnan rice production areas of China. PCR amplification and pathogenicity assays ofAvrPiz-tshowed that 202 isolates (64.7%) heldAvrPiz-talleles and were avirulent to IRBLzt-T (holdingPiz-t). There were 42.3-83.3% avirulent isolates containingAvrPiz-tamong seven regions in Yunnan Province. Meanwhile, 11 haplotypes ofAvrPiz-tencoding three novelAvrPiz-tvariants were identified among 100 isolates. A 198 bps insertion homologous to solo-LTR of the retrotransposon inago2 in the promoter region ofAvrPiz-tin one isolate and a frameshift mutation of CDS in another isolate were identified among 100 isolates, and those two isolates had evolved to virulent from avirulent. Synonymous mutation and non-AUG-initiated N-terminal extensions keeps theAvrPiz-tgene avirulence function inM. oryzaefield isolates in Yunnan. A haplotype network showed that H3 was an ancestral haplotype. Structure variance for absence (28.2%) or partial fragment loss (71.8%) ofAvrPiz-twas found among 39 virulent isolates and may cause theAvrPiz-tavirulence function to be lost. Overall,AvrPiz-tevolved to virulent from avirulent forms via point mutation, retrotransposon, shift mutation, and structure variance under field conditions.

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