Genetic diversity of <i>Ustilago scitaminea</i> Syd. in Southern China revealed by combined ISSR and RAPD analysis

Abstract

The polymorphism and similarity relationships among 35 mating-type isolates of Ustilago scitaminea collected from Southern China were determined with random amplified polymorphic DNA (RAPD) and inter-simple  sequence repeat (ISSR) analyses. These fungal isolates were collected from 16 sugarcane cultivars including F134 that is resistant to the physiological race 1 but susceptible to the race 2 of U. scitaminea, and N: Co376  that is immune to both races 1 and 2. Unweighted pair group method with arithmetic mean (UPGMA) cluster  analysis revealed that the U. scitaminea isolates could be divided into 2 groups with a coefficient of 0.74. The  first group comprises two isolates collected from the sugarcane cultivar F134, while the remaining 33 isolates were clustered into the second group. The second group was further divided into two subgroups with most of  the isolates from Guangdong Province which clustered in the same subgroup, and all the isolates from Guangxi  and Yunnan Provinces were clustered in another subgroup. Given that the member of the second group could  infect the cultivar N:Co376, which is immune to the races 1 and 2, our results suggest that majority of U.  scitaminea in sugarcane-producing regions of Southern China may belong to or genetically similar to race 3.

Key words: Ustilago scitaminea, sugarcane, inter-simple sequence repeat (ISSR), random amplified  polymorphic deoxyribonucleic acid (DNA) (RAPD), genetic diversity.