Characterization of psychrotolerant rhizobacteria for Zn biofortification in lentil (Lens culinaris L. Medikus)
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Date
2018
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Punjab Agricultural University, Ludhiana
Abstract
Seventy psychrotolerant rhizobacterial isolates were evaluated for their PGP traits at
10°, 20° and 30°C. Highest IAA production was recorded with isolates PRh-9, PRh-14, PRh-
15, PRh-60, PRh-61 and that was confirmed by HPLC (8.98, 4.91, 5.66, 2.73 and 1.62 μg/ml
respectively). Isolate PRh-14 recorded maximum Zn-solubilization potential of 354, 304.8
and 284.5 ppm at 10°, 20° and 30°C. It also recorded the maximum P-solubilization
efficiency, gibberellins, EPS production and biofilm formation at 10°, 20° and 30°C. Eleven
isolates amplified acdS gene which confirmed the presence of ACCD activity. Maximum
naringin and quercetin production was shown by isolate PRh-61 and PRh-9, further confirmed
by TLC studies. Highest antagonistic activity was recorded by PRh-9 against Rhizoctonia
bataticola and Fusarium oxysporum (33.3% and 48.1% respectively) and was also established
by SEM analysis. Potent siderophore, salicyclic acid and HCN producers were PRh-9, PRh-
61 and PRh-60. The SEM analysis of root surface revealed that coinoculation with Rhiobium
and PRh-14 helped in maintaining the root integrity owing to biofilm formation on the root
surface. Under field conditions coinoculation of Rhizobium with PRh-15, PRh-14, PRh-9,
PRh-61, PRh-60 and PRh-30 further increased by grain yield by 1.7, 4.4, 3.7, 2.5, 2.09, 1.5%
respectively, over Rhizobium alone. A significant increase in the grain and straw zinc content
was recorded with the treatment R+PRh-14 (105.9 and 141.0 ppm respectively). The DGGE
analysis of soil DNA depicted a composite banding pattern that reflected a high microbial
diversity. The promising rhizobacterial isolates were identified as PRh-9 (Pseudomonas
flourescens), PRh-14 (Aeromonas hydrophila), PRh-60 (Lysinibacillus fusiformis) and PRh-61
(Pseudomonas korensis) based on 16S rDNA sequencing.
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