Synthesis and Evaluation of Chitosan and Microbial Extract Based Nanoparticles Against Major Plant Pathogens

Abstract

Sixteen isolates of fluorescent Pseudomonas, twenty isolates of Bacillus subtilis newlineand fifteen isolates of Trichoderma sp. were isolated from 16 different crops newlinerhizosphere. Ten isolates of Saccharomyces cerevisiae were isolated from different newlinefruits surface. The superior isolates showed maximum zinc utilization (four), newlinesiderophore production (three) and iron tolerant ability (one) were selected for newlinenanoparticles synthesis. Zinc (ZnNPs) and iron nanoparticles (FeNPs) were synthesized newlinefrom extract of P. fluorescens, B. subtilis, T. harzianum, S. cerevisiae and chitosan. newlineUV-vis spectrophotometer analysis of ZnNPs and FeNPs showed absorbance maxima at newline355-365 nm and 400-425 nm respectively. Particle Size Analyser revealed that, smaller newlineaverage diameter of the particles were recorded in Pf-ZnNPs (21.40 nm). Atomic Force newlineMicroscope and Scanning Electron Microscope observations confirmed the circular to newlineirregular in shape of ZnNPs and FeNPs with the size of 15-98 nm. newlineCh-ZnNPs were found to be superior with maximum inhibition of growth of newlineXanthomonas axonopodis pv. punicae (25.33 mm) at 1250 ppm followed by newlineXanthomonas axonopodis pv. citri (22.00 mm), Xanthomonas oryzae pv. oryzae newline(15.67 mm) and Ralstonia solanacearum (15.67 mm). Pf-ZnNPs, Bs-ZnNPs and newlineSc-ZnNPs completely inhibited the mycelial growth of Fusarium oxysporum f. sp. newlineciceri and Sclerotium rolfsii. Th-ZnNPs showed complete inhibition (100 %) of newlinemycelial growth of F. oxysporum f. sp. ciceri at 500 ppm. Compared to ZnNPs, FeNPs newlineshowed lesser inhibition on plant pathogens. Glasshouse evaluation of nanoparticles newlineagainst bacterial wilt of tomato revealed that, lowest wilt incidence was recorded in newlineCh-ZnNPs (16.67 %) at 1250 ppm. In case of citrus canker, lowest disease severity was newlinerecorded in Bs-ZnNPs (8.89 PDI) at 1250 ppm. The soaking of onion, chilli and maize newlineseeds in nanoparticles increased the seed germination, seedling length and vigour. newlineThe nanoparticles did not show any phytotoxic symptoms on chilli, onion, tomato and newlinemaize up to 1250 ppm. newline