The Genetic Structure And Sexual Reproduction Characteristics Of Phytophthora Infestans In Yunnan Province

Late blight caused by Phytophthora infestans is the most devastating disease topotato production in Yunnan. Analysis of the population genetic variation ofPhytophthora infestans is essential for understand the disease epidemiology anddeveloping disease control measures.168isolates were determined for mating typeand mitochondrial DNA haplotype. In addition, the gene recombination and geneticdiversity of single-oospore isolates was analyzed using SSR primers.The main resultsin the study are as follows:1.248isolates of P. infestans were collected from the major potato production areasin Yunnan province.2.168isolates were inspected for mating type using confrontation culture methodand molecular marker method. Among168isolates of P. infestans,91isolatesbelonged to A2mating type with the frequency of54%;77isolates were A1A2mating type with the frequency of46%.3.168isolates were inspected for mitochondrial DNA haplotype, the result showedthat all isolates was Ia,Ia is the predominance mtDNA haplotypes in Yunnan P.infestans groups.4. Using ten pairs of SSR primers investigate genetic diversity of24isolates fromthe same cropland in Yunnan,Cluster analysis showed that, in the similaritycoefficient of0.91,24isolates can be divided into4groups,group III were fond tobe dominant,comprising14isolates with the frequency of58.3%.5.240F1progeny isolates from four Parents (①DB1204X DN111、②Jche1204XDN111、③XD1213X80029、④JCHE1207X80029) was obtained，the240F1progeny isolates were inspected for mating type,the result showed that55isolatesbelonged to A1mating type with the frequency of23%,150isolates were A2mating type with the frequency of62.5%,35isolates were self-fertile mating typewith the frequency of14.5%,indicated that A1tape and A2type were not a1:1proportion in progenies.6. Using thirteen pairs of SSR primers to test the recombination of187F1progenyisolates,155F1progeny isolates have the same band with their parents strains,32F1progeny isolates be tested have genetic recombination. From the above results, it was concluded that isolates which were identified fromyunnan area in2012-2013were determined for mating type and mitochondrial DNAhaplotype，the result showed that A1mating type and self-fertile mating type has notbeen detected and all isolates was Ia. Using SSR primers investigate genetic diversityof24isolates from the same cropland in yunnan,cluster analysis showed that YunnanP. infestans exhibited a relatively low genetic diversity at population level. The matingtype of240F1progeny isolates from four Parents were tested, the result showed thatobservations of wide variation in the ratios of mating types in the progeny of differentcrosses, A1tape and A2type were not a1:1proportion in progenies. Using SSRprimers investigate genetic diversity of187F1generations, the result showed that32F1progeny isolates exhibited genetic recombination。...