ISOLATION, CHARACTERIZATION AND MANAGEMENT OF Alternaria solani CAUSING EARLY BLIGHT IN TOMATO THROUGH DIFFERENT BACTERIAL STRAINS

Abstract

Tomato is grown widely in almost 140 countries having annual production of 151 million tons and is mostly grown in South America. Pure culture of Alternaria solani isolated from twig and leaf samples was prepared. The fungal colonies were cultured in Broth of MEA and PDA for 5-7 days at 25oC. Cetyl-trimethyl-ammonium-bromide (CTAB) extraction technique was applied for DNA extraction of A. solani with little modification. Molecular identification with ITS primers of isolated fungi was undertaken and a 594bp size of the band was obtained. The DNA sequence was submitted to Gen Bank having Gene Bank no. MN200940. The sequenced data was 100% similar to the Alternaria isolate Alt-C81 of Gen Bank accession code MN044802. Biological control agents were applied and data were collected at an interval of 3, 5, 7 and 10 days. The maximum inhibition percentage after 3 days (84.23%) was recorded by Azospirillum lipoferum (RB-38) while the lowest inhibition (44.84%) was recorded by Bacillus subtilis (RB-59). After 7 days of incubation, the highest inhibition (89.13%) was observed by using A. lipoferum (RB-38) and the lowest (60.57%) by Bacillus spp. (RB-43), respectively. After 10 days of incubation, the highest inhibition percentage (95.91%) was recorded by B. subtilis (RB-59) and the lowest by Bacillus thuringiensis (RB-16) with PI of 13.71% respectively. These results suggest that the bacterial isolates studied have a good potential to be used as biocontrol agents of A. solani in tomato plants for the sustainable production of tomatoes without using fungicides. It not gives a good perspective for sustainability and also reduce the environmental pollution.