Analysis Of Mitochondrial DNA Haplotypes And Thermal Adaption Of Phytophthora Infestans In China

Late blight caused by the oomycete pathogen Phytophthora infestans is aseriously destructive disease to potato. Understand the population structure andmigration situation of P. infestans is of great significance to control potato late blightscientificly.In this study, mitochondrial DNA haplotypes of P. infestans in total765isolates,collected from Fujian,Yunnan, Guizhou, Gansu etc in2010,2011and2012weredetected by PCR-RFLP. The distribution of the nine P. infestans population wasdetermined so as to understand the population structure of P. infestans in theseregions.The growth rates of Phytophthora infestans populations from Yunnan, Guangxi,Gansu etc seven regions were detected. Combining the result of SSR, the thermaladaption mechanism of P. Infestans was analyzed initially. The main research results areas follows:Three haplotypes including Ia, IIa and IIb were detected.659isolates(107fromGuizhou,89from Fujian(Fuzhou,Changle,Zhangzhou),89from Yunnan,85fromXiapu2011(collected in2011),95from Gansu,68from Ningxia,19from Chongqing,90from Xiapu2012(collected in2012),17from Wuhan) were Ia, being the mostwidely distributed type.81isolates(51from Guangxi,5from Guizhou,12fromFujian(Fuzhou,Changle,Zhangzhou),6from Xiapu2011(collected in2011),5fromXiapu2012(collected in2012),2from Wuhan) were IIb.25isolates(3fromFujian(Fuzhou,Changle,Zhangzhou),5from Yunnan,9from Ningxia,3fromChongqing,5from Wuhan) were IIa. None of Ib was detected in the research. Theresults showed the distributions of P. Infestans populations were differentsignificantly.Measuring the growth rates of P. Infestans in five temperature gradients showedthe growth rates in19℃were generally higher. With increase or decrease oftemperature, the frequency of higher growth rates was declining. Thermal adaption ofP. Infestans from different regions were different, it is possibly related to the mean temperature of collecting areas. Calculate the degree of genetic differentiation by theresults of SSR Combining the differences of growth rates in different temperatures,the contributions of genetic drift to phenotypic plasticity were analyzed.