HIGH THROUGHPUT MICROTITRE BASED SCREENING AND MODE OF ACTION OF PLANT FUNGAL AND BACTERIAL SECONDARY METABOLITES FOR THE MANAGEMENT OF Colletotrichum spp CAUSING FRUIT ROT OF CHILLI Capsicum annuum L

Abstract

newline Chilli (Capsicum annuum L.) is an important commercial, vegetable and spice crop in India. newlineThe fungal disease mainly anthracnose/ die-back/ fruit-rot of chilli is an economically important newlinedisease causing serious losses and contribute to the major share of crop loss. Hence, an attempt was newlinemade to isolate the pathogens associated with this disease. The pathogens such as Colletotrichum newlinecapsici (leaf), C. siamense (stem), C. gloeosporioides (green fruit) and C. capsici (ripened fruit) newlinewere isolated from different parts of infected plant and identification was done through cultural, newlinemorphological and molecular characterization. Total of 30 plant samples and eight bacteria and newlinefungi were successfully collected and characterized and then were used for extraction of secondary newlinemetabolites. These extracts were tested against C. capsici and C. gloeosporioides. Among the newlinedifferent screening methods, microtitre plate assay and resazurin cell viability tests were proved to newlinebe best in screening of extracts against the pathogens, which were equally appropriate methods as newlinethat of poisoned food technique. In all the screening methods, P. hysterophorus, O. tenuiflorum, T. newlineharzianum, D. eschscholtzii, B. diminuta and B. subtilis were found to be superior in inhibiting the newlinepathogens at higher concentration. The potential plant extracts and crude extracts of bio-agents have newlineshown the adverse effects on cell wall and cell membrane of C. capsici and C. gloeosporioides and newlinehave ability to rupture the cell membrane leading to leakage of the protoplasmic content and also newlinehave an inhibitory effect on conidial germination, efficient in reducing the dry mycelial weight and newlineactivity of cellualse and pectinase enzymes and also increased the phenolic content in the treated newlinefruits. The GC-MS analysis of potential extracts have shown the presence of active components. newlineNone of the eight bio-active compounds have shown binding to the active site of cellulase (6MVI). newlineThe bioactive compound 9, 12-Octadecadienoic acid, methyl ester, (E,