@article{LIU2023, 
author = {RUI LIU and YuHan ZHAO and XinYi GU and YanXia WANG and XueHui JIN and WeiHuai WU and YaLing ZHANG},
title = {Distribution and Variation Analysis of AVR-Pita Family in Magnaporthe oryzae from Heilongjiang Province and Hainan Province},
year = {2023},
journal = {Scientia Agricultura Sinica},
volume = {56},
number = {3},
pages = {466-480},
keywords = {Magnaporthe oryzae, AVR-Pita family, mutation, avirulence gene, Heilongjiang Province, Hainan Province},
url = {https://www.sciopen.com/article/10.3864/j.issn.0578-1752.2023.03.006},
doi = {10.3864/j.issn.0578-1752.2023.03.006},
abstract = {【Objective】By detecting the distribution and variation characteristics of the AVR-Pita family in different Magnaporthe oryzae strains from Heilongjiang Province and Hainan Province, the pathogenic phenotypes of the variation types were understood, which provided a reference for the screening and breeding of disease-resistant germplasm in the region.【Method】Six pairs of specific primers were designed for the promoter region and CDS region by referring to the AVR-Pita family sequence published in NCBI. DNA was extracted from 397 single spore strains of M. oryzae collected from different regions of Heilongjiang Province and Hainan Province in 2020, and PCR amplification was performed. By electrophoresis test results, representative strains from different regions were selected to sequence the amplified fragments. The sequencing results were compared with the corresponding base and amino acid sequences in NCBI, and the avirulence function of different variation types of M. oryzae strains was verified by using rice resistant single gene lines.【Result】In the PCR electrophoresis results, the M. oryzae strains in Heilongjiang Province carried all the genes to be tested, which were widely distributed and had a high detection frequency. However, only AVR-Pita1 and AVR-Pita2 were carried by M. oryzae strains in Hainan Province, and concentrated in low frequency. The results of avirulence gene composition analysis showed that the strains of M. oryzae in Heilongjiang were complex and diverse, and the genotypes were more abundant than those in Hainan. The sequencing results of PCR products showed that the AVR-Pita family was divided into 19 types with point mutation, insertion and deletion as the main variation types, and the variation types of strains from different M. oryzae populations were specific. Ten variation types were detected in AVR-Pita1, among which AVR-Pita1- (1-5) was a unique variation type of M. oryzae strains in Heilongjiang Province, and AVR-Pita1- (6-10) was a unique variation type of M. oryzae strains in Hainan Province. After functional verification of these ten variation types, it was found that the avirulence functions were lost. Eight variation types were detected in AVR-Pita2, among which AVR-Pita2- (1-4) was a unique variation type of M. oryzae strains in Heilongjiang Province, and AVR-Pita2- (5-8) was a unique variation type of M. oryzae strains in Hainan Province. After functional verification, it was found that the avirulence functions were lost. Only one variation type (AVR-Pita3-1) was detected in AVR-Pita3 in Heilongjiang Province.【Conclusion】The AVR-Pita family in Heilongjiang and Hainan populations were mutated alleles. After pathogenicity identification, all mutation types could not be identified by the corresponding resistance genes Pi-ta and Pi-ta2. Therefore, the resistance genes Pi-ta and Pi-ta2 can be used to polymerize other resistance genes to ensure the disease resistance of varieties in the process of disease resistance breeding and utilization of rice blast in Heilongjiang Province and Hainan Province. At the same time, the distribution and variation types of AVR-Pita family in M. oryzae strains from different geographical sources are specific.}
}