Effect of elevated temperature on quorum sensing signal molecule (N-Acyl Homoserine Lactone) production of Pectobacterium carotovorum subsp. carotovorum in tomato

摘要

Gram negative plant pathogenic bacteria regulatespecific gene expression in a population density dependantmanner by sensing level of Acyl-Homoserine Lactone (HSL)molecules which they produce and liberate to the environment,called Quorum Sensing (QS). The production of virulence factors(extracellular enzyme viz. cellulase, pectinase) in Pectobacteriumcarotovorum subsp carotovorum (Pcc) is under strong regulationof QS. The QS signal molecule, N-(3-oxohexanoyl)-L-HomoserineLactone (OHHL) was found as the central regulatory system forthe virulence factor production in Pcc and is also under strictregulation of external environmental temperature. Under sevendifferent incubation temperatures (24o C, 26oC, 28oC, 30oC, 33oC,35oC and 37oC) in laboratory condition, highest amount ofOHHL (804 violacein unit) and 3-unsubstituted HexanoylHomoserine Lactone (HHL) and highest (79 %) Disease SeverityIndex (DSI) was measured at 33oC.