Studies on plant growth promoting fluorescent pseudomonads of Uttara Kannada District of Karnataka State

Abstract

Of the 133 fluorescent pseudomonads from Uttara Kannada district, 86 were newlineidentified as Pseudomonas fluorescens, 45 as P. aeruginosa and two as P. aureofaciens. newlineSeventy isolates released 11.85 to 60.60 % Pi at 14 days. The IAA and GA production ranged newlinefrom 30-984 and#1048656;g/l and 55-342 and#1048656;g/l of broth respectively and 22 isolates produced cytokinins newline(4.07-58.44 and#1048656;g/l). While 67 produced alkaline protease, 28 had high chitinolytic activity. Sixtyseven newlineisolates antagonized one or other plant pathogens; 49 were inhibitory to A. carthami, newline39 to F. oxysporum f. sp. carthami (Foc), 32 to S. rolfsii, 23 to R. bataticola, 42 to X. newlineaxonopodis pv. punicae (Xap), 59 to X. axonopodis pv. malvacearum, 42 to R. solanacearum newlineand 41 to X. axonopodis pv. citri. Of these, 41 produced HCN and all of them produced newlinesiderophores. Out of 28 potential antagonists, 26 produced antimicrobials. Five antagonists newlineagainst each of the 4 fungal pathogens produced volatile metabolites which inhibited S. rolfsii, newlineA. carthami and Foc. Fifteen isolates with multifunctional properties were evaluated in pot newlinecultures. In safflower, DF 75 was the best for growth promotion. When safflower was newlinechallenged with Foc, MDF 449(1) recorded best growth promotion coupled with the least wilt newlineincidence and highest ISR activity. In pomegranate, MDF 449(1) was best for growth newlinepromotion. When pomegranate was challenge inoculated with Xap, DDF 347(1) showed newlinemaximum growth promotion coupled with the least bacterial blight intensity and highest ISR newlineactivity in leaves. The RAPD analysis of 25 isolates indicated tremendous diversity. The newlinedendrogram for pooled data showed nine clusters. The Shannon s index of pooled data was newline0.71 indicating high diversity the maximum being in dry deciduous forest (0.79). The richness newlineindex was 0.65 indicating that fluorescent pseudomonads are not distributed equally. Low newlineevenness index of 0.26 indicated dominance of P. fluorescens over the others. newline