Abstract
Physalis minima is an herbaceous plant and inhabitant of the porous and organic matter containing soil of bunds in crop fields, wastelands, around the houses, and on the roadsides. S. rolfsii is soil borne and it can infect over 500 plant species of different families. It is of interest to study the pathogenesis of S. rolfsii on P. minima. The S. rolfsii isolated from P. minima (physr1) was characterized by morphology and sequence of Internal Transcribed Spacer (ITS) region. The population structure determination and phylogenetic analysis showed the isolate physr1 significantly differs from other isolates. The null hypothesis of equal evolutionary rate was rejected throughout the Maximum likelihood (ML) tree topology of different S. rolfsii ITS sequences. The site-specific mean (relative) evolutionary rate analysis showed that most of the sites (80.59 % sites) evolved at a slower rate than average. Finally, the result of Tajima's neutrality test indicated that the population of S. rolfsii has recently begun to expand and that's why the pathogen was infecting the new host P. minima and pose a serious threat of infecting several other cropped and non-cropped hosts.