Genetic relatedness among Fusarium populations associated with sugarcane wilt in India: bridging molecular variability and phylogenetic diversity

Abstract

Fifty Fusarium isolates associated with sugarcane wilt that widely differed in their cultural characters and geographical origin were subjected to molecular characterization using different molecular markers, viz. RAPD, rDNA-IGS-RFLP and ISSR. Among the markers, ISSR generated 98% polymorphism followed by RAPD and rDNA-IGS-RFLP with 97% and 92% polymorphism, respectively. The Fusarium population was divided into two groups, namely A and B by RAPD analysis and such grouping remained consistent with ISSR. ISSR and RAPD grouped 76 - 86% of isolates as F. sacchari in group A and the remaining isolates as other species isolates in a separate group B. The dendrogram of IGS-RFLP had many clusters in which the isolates that belonged to species other than F. sacchari separated first in many small clusters as in RAPD. The detailed phylogenetic analyses established that ISSR is more efficient than RAPD and rDNA-IGS-RFLP for grouping the isolates. The detailed investigation taken up to define genetic variability among the Fusarium population associated with sugarcane wilt in India correlates with earlier established taxonomy and pathogenicity data. Our investigation clearly indicates F. sacchari as the major causative organism of sugarcane wilt