Molecular Characterization and Genetic Variation in Ceratocystis fimbriata Ell. and Halst. on Pomegranate

Abstract

Fifteen isolates of Ceratocystis fimbriata collected from different locations in Karnataka were characterized using ITS gene technology. It produced an amplification size of 600–650 bp, which indicated that all the isolates belong to the genus Ceratocystis, thus confirming the identity of the pathogenic isolates. To test genetic variability, isolates were analyzed using microsatellite markers. An UPGMA dendrogram for genetic variation among the isolates showed that all the isolates fell into two major clusters. The first cluster consisted of isolate Cf-10 and the second cluster was further divided into two sub-clusters. Sub-cluster one consisted of isolate Cf-2. Sub-cluster two was again divided into five groups. The first group included isolate Cf-13, the second group consisted of isolate Cf-14, the third group included isolates Cf-1, Cf-4, Cf-6, Cf-7, Cf-8 and Cf-9, the fourth group included Cf-5 and Cf-11, and the fifth group consisted of Cf-3, Cf-12 and Cf-15. The dissimilarity coefficient ranged from 0.00 to 0.20 among the isolates. Isolates Cf-1, Cf-3, Cf-4, Cf-5 Cf-6, Cf-7, Cf-8, Cf-9, Cf-11, Cf-12 and Cf-15 were found to be highly similar, as their dissimilarity coefficient was zero. Maximum dissimilarity (0.20) was found between isolate Cf-10 and all the other isolates, suggesting they were genetically distinct.

Genetical Variability among Ceratocystis fimbriata Isolates Causing Wilt Disease of Pomegranate

“…reported that "genetic studies in populations of the fungus in Costa Rica, Colombia, and Bahia may have been introduced on cacao cuttings; whereas populations in Rondonia, Brazil, and Western Ecuador appear to be native. The fungal genotype present in Bahia is similar to those found in Rondonia and may have been introduced on propagative material with witches' broom resistance" [10]. "UPGMA dendrogram for genetic variation among the isolates of C. fimbriata showed that all the isolates fell into two major clusters, and the isolates from different districts did not show a specific pattern of similarity according to geographical region.…”