| Late blight caused by the oomycete pathogen Phytophthora infestans is the mostdevastating disease of potato in the world. Late blight occurs in all the major potato-growingregions in China, which leads to serious losses. Understanding of P. infestans populationstructure is essential for development of effective late blight control themeasures.In this study, mitochondrial DNA haplotypes of P. infestans627isolates, collected in2009and2010in the main potato production regions in Northwest China, were assessedusing a PCR-RFLP based method, and their distribution was analyzed. In addition, the matingtypes of P. infestans collected from Qinghai Province in2010were determined. The mainresults are as follows:1. A total of168single-lesion isolates were purified from potato collected from Qinghaiin2010, and154of them were determined for the mating types. The result showed that thepercentages of A1, A2and self-fertile types in were76.6%,20.1%and3.3%, respectively;2. Using reference P. infestans A1and A2strains whose mitochondrial DNA haplotypeswere known, a total of231P. infestans isolates collected from Ningxia, Gansu and Shaanxi in2009were determined using a PCR-RFLP based method, and three haplotypes, Ia、IIa andIIb were detected. Of231isolates,132(27from Ningxia,44from Gansu, and61fromShaanxi) were IIa, being the most widely distributed type. The Ia haplotype included98isolates (72from Ningxia and26from Gansu province). The IIb type was detected in one case,which was isolated from Ningxia.3. Analysis of P. infestans380isolates collected from Ningxia, Gansu, Qinghai, andShaanxi in2010showed the presence of haplotypes Ia, IIa and IIb. Compared with that of2009, the haplotypes Ia isolates were dominant, being72.6%of total380isolates examined.Among the276Ia isolates,119were from Ningxia,130from Gansu, and27from Qinghai.The haplotype IIa included101isolates,2from Ningxia,97from Qinghai, and2fromShaanxi Three IIb isolates were detected from Ningxia. |
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