Molecular Diagnosis and Characterization of a Geminivirus Causing Leaf Curl Disease of Tomato in Mid Hills of Northern India

摘要

Geminiviruses are small isometric particles which contain either one or two circular single stranded DNAs. The family Geminiviridae comprises of four genera: Mastrevirus, Curtovirus, Topocuvirus and Begomovirus. Among begomoviruses, one of the most important virus is TYLCV which infects an economically important food crop i.e. tomato [Lycopersicon esculentum), all over the world. TYLCV is also prevalent in different regions of India. Five samples from different tomato growing areas of Himachal Pradesh were collected for serological detection of TYLCV using DAS-ELISA. All samples reacted positively with the antisera. In further confirmation studies, CP (coat protein) gene based specific primer pairs for TYLCV were designed and tested. CP gene was amplified from two isolates and a 771 bp long CP sequence was amplified, sequenced and submitted to NCBI database (Acc no-KC253231). TYLCV, the test virus was confirmed to be a begomovirus on the basis of phylogenetic analysis while comparing it with othergeminiviruses. On comparison with other Indian tomato leaf curl viral isolates, it was found to be closely related to Dharwad isolate (GI1160428) and not to native isolate (GI1244840), which indicates it's origin in other than North Indian region and evolution of a new viral strain.