Abstract
Aim: Isolation,
screening and characterization of beneficial rhizosphere bacteria associated
with healthy (field-resistant) coconut palms in root (wilt) disease endemic
hotspot areas of Kerala.
Methodology: One hundred and ten rhizobacterial isolates
associated with healthy coconut palms of root (wilt) diseased tract of Kerala
were isolated and screened in-vitro for IAA production and
solubilization of fixed forms of mineral nutrients. Seven isolates showing
multiple phytobeneficial properties were characterized and the selected
isolate was tested for its biopriming effect on maize.
Results:
Of the total isolates screened, 54 isolates produced IAA. Among the nutrient
solubilizers, silicate solubilizers (57%) and phosphate solubilizers (48%)
dominated. Of the seven isolates with multiple phytobeneficial properties,
five rhizobacterial isolates belonged to Enterobacteriaceae family including
three Enterobacter spp. The isolate T4HFB9 belonged to Acinetobacter
sp. The green fluorescent Pseudomonas isolate K3HPSB2, showed 99% sequence
similarity with Pseudomonas migulae. Seed biopriming of maize with Pseudomonas
sp. strain K3HPSB2 recorded significant increase in germination
percentage and seedling vigour index over untreated control.
Interpretation: Disease-resistant coconut palms in RWD
endemic tracts host a good proportion of phytobeneficial rhizosphere
bacteria,with demonstrable multiple plant growth promoting traits.
Multi-nutrient solubilizing Pseudomonas sp. with bioinoculant
prospects has been selected for further studies on bio-priming for palm
health management in RWD endemic tracts.
Key
words:
Coconut, Nutrient solubilizers, Phytobeneficial, Pseudomonas,
Rhizobacteria
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