Discovering The Molecular Variations Among Distinct Sporisorium scitamineum Isolates Using Sequence-Related Amplified Polymorphism (SRAP) Markers

Sugarcane smut caused by the biotrophic fungus Sporisorium scitamineum is one of the major sugarcane diseases that causes considerable yield loss globally. Recent years have witnessed increasing smut incidences in most of the sugarcane growing tracts of India. Pathogenic races of sugarcane smut have been observed in several countries. However, limited information is available from India, and so, in this study, we have assessed the genetic variability among representative isolates of S. scitamineum . Five smut isolates collected from different sugarcane cultivars from distinct geographical locations of sugarcane that are cultivated in India were chosen for investigating their genetic diversity using Sequence-related amplified polymorphic (SRAP) markers. Among the forty-five SRAP primer combinations evaluated, 27 primer sets exhibited polymorphisms. A total of 625 traceable loci (bands) were scored, out of which 61 bands were polymorphic with a range of 200–3000 bp. The genetic similarity indexes among the 5 test isolates were calculated using Jaccard’s coefficient and a relatively low level of genetic distance was found. The genetic dissimilarity between the isolates ranged from 0.041 to 0.054. The UPGMA-based cluster analysis grouped the isolates into two clusters, which accurately corroborated with the disease phenotyping assessments, where the relative virulence of these five smut isolates using two host standards categorized them into two distinct groups as high and low virulent isolates. Besides, the present study has identified a set of SRAP markers that could clearly categorize the virulence nature of S. scitamineum isolates, even with a low degree of genetic dissimilarity.