unraveling the functionality of tomato pgpr fluorescent pseudomonas interaction for the management of bacterial wilt caused by ralstonia solanacearum smith yabucchi et al

Abstract

Tomato is one of the important culinary vegetable in Indian tradition. The contribution of newlinetomato to post harvest industry and Indian economy is commendable. Tomato crop being infected newlineby several soil borne diseases in Indian sub-continent, among the serious diseases the bacterial wilt newlinedisease caused by Ralstonia solanacearum is a serious disease that leads to severe yield loss. The newlineclimatic change in India way through the emergence of disease incidence in new areas. In the newlinepresent study, survey has been conducted at Othakalmandapam (10.8744° N, 77.0017° E) and newlineKinathukadavu (10.8225° N, 77.016° E) region of Coimbatore district, Tamil Nadu to find the newlinebacterial wilt incidence in tomato fields. Tomato bacterial wilt disease incidence was noticed by newlinevisual symptoms and confirmed preliminarily by bacterial ooze test. Totally four newlineR. solanacearum bacterial strains were isolated from Othakalmandapam (OKM1 and OKM2) and newlineKinathukadavu (KK1 and KK2). All the four strains produced typical pink centred white fluidal, newlineopaque and irregular shaped colonies. All the isolated R. solanacearum strains were subjected to newlinepathogenicity assay where the KK2 strain from Kinathukadavu was found more virulent than other newlinestrains in tomato plants. The KK2 strain R. solanacearum produced wilt symptom at fifth DAI and newlineleads to death of whole seedlings at fifteenth DAI. The infected plants were subjected to ooze test newlineand Field Emission Scanning Electron Microscopy image analysis. The FESEM images showed newlinethe biofilm formation and blockage of vascular bundles by bacterial secretion in infected tomato newlineplants. For the confirmation of R. solanacearum, PCR was carried out using R. solanacearum newlinespecific primer Rs-sp targeting ipxC region that amplified at 282 bp amplicon. The virulent strain newlineKK2 was subjected to 16s rRNA sequencing that showed 93 per cent similarity to newlineR. solanacerarum and further submitted in GenBank database (MH666127.1) newline