中国农业科学2018，Vol.51Issue(6)：1079-1088,10.DOI:10.3864/j.issn.0578-1752.2018.06.007
谷瘟病菌无毒基因型鉴定及分析
Identification and Analysis of Magnaporthe oryzae of Foxtail Millet Avirulence Genes
摘要
Abstract
[Objective]The objective of this study is to identify avirulence genes (Avr-genes) of Magnaporthe oryzae,understand the distribution and variation of Avr-genes in the epidemic strains of different regions,and to provide a reference for further study of the mechanism of Avr-genes variation in M.oryzae.[Method]A total of 76 strains of M.oryzae were isolated from different regions of millet growing area in northern China.The genomic DNA of 76 M.oryzae strains was extracted and used as a template for PCR amplification using the specific primers designed according to the 7 Avr-genes cloned from rice blast.AGE (agarose gel electrophoresis) analysis and sequencing of the PCR products were used to analyze the distribution of Avr-genes in M.oryzae strains of different regions from foxtail millet.[Result]The amplification rate of ACE1,Avr-pita,Avr1-CO39 andAvrPiz-t genes was 100％ in 76 strains of M.oryzae and the amplification rate of avirulent genes Avr-pik,Avr-pia and Avr-pii was 63.2％,42.1％ and 21.1％,respectively.The amplification of Avr1-CO39 in the strains P11 and P34 was about 490 bp larger than the expected fragments.Sequencing of the Avr1-CO39 in the strains P 11 and P34 showed that the Avr1-CO39 sequences in strains P 11 and P34 were identical and the promoter region contained a 490 bp inserted fragment which shared 99.16％ similarity with non-LTR retrotransposon:Mg-SINE.A high level of Avr-pita polymorphisms were found in M.oryzae and the major variation was single nucleotide variation,including single base insertion,deletion,and SNP of multiple loci.The main sequence variation ofAvr-pia was the absence of the whole Avr-gene,and their sequencing verification results showed that there were 4 genotypes of Avr-pia allele in the strains.The Avr-pia-A was identical to the reference sequence (AB498873.1) and contained 10 strains.Avr-pia-B contained 20 strains,and there were C/T,G/T and C/A mutations at-116,-109,and-16 bp sites,but the CDS region of Avr-pia-B was the same as the reference sequence.The Avr-pia-C type contained only the strain P10,and there was a T/G mutation at +150 bp,but it is a synonymous mutation.The Avr-pia-D contained only the strain P18,and there was a C/T mutation at +212 bp site,which resulted in the mutation of coding amino acid from threonine to isoleucine.The Avr-pii of M.oryzae contained 3 alleles.The Avr-pii-A was the same as the reference sequence (AB498874.1) and contained 14 strains.An A/G mutation was found in Avr-pii-B and Avr-pii-C at +139 and +64 bp sites,respectively,which caused the amino sequence in the site to mutate from threonine to alanine..Avr-pii-B and Avr-pii-C were both reported for the first time.The haplotype analysis showed that AG2 containing 23 strains was the dominant type,which accounted for 30.2％ of the tested strains.[Conclusion]Avr-genes ACE1,Avr-pita,Avr1-CO39 and AvrPiz-t had no geographical origin difference and the frequency distribution of Avr-genes Avr-pik,Avr-pia and Avr-pii varied in different regions.The AG2 haplotype was predominant in M.oryzae from foxtail millet,followed by AG1 and AG5 haplotypes.关键词
谷子/谷瘟病菌/无毒基因/变异Key words
foxtail millet/Magnaporthe oryzae/avirulence gene/mutation引用本文复制引用
任世龙,白辉,王永芳,全建章,董志平,李志勇,邢继红..谷瘟病菌无毒基因型鉴定及分析[J].中国农业科学,2018,51(6):1079-1088,10.基金项目
国家现代农业产业技术体系(CARS-07-13.5-A8)、河北省优秀专家出国培训项目 （CARS-07-13.5-A8）
