MOLECULAR DIVERSITY OF RHIZOBIA ASSOCIATED WITH LEGUMINOUS TREE SPECIES GROWN UNDER DIFFERENT AGRO-CLIMATIC ZONES OF HIMACHAL PRADESH
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Date
2023-05-31
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UHF,NAUNI
Abstract
ABSTRACT
The present investigations were conducted to determine the genetic diversity of
rhizobia with plant growth promoting traits associated with A. lebbeck and L.
leucocephala grown under different agro climatic zones of Himachal Pradesh by
amplified ribosomal DNA restriction analysis (ARDRA). The preliminary
identification based on different authentication tests, viz. congo red test, bromothymol
blue test, growth in Hofer’s alkaline broth and ketolactose medium a total of 105
isolates were tentatively identified as Rhizobium sp. Out of 105 isolates, forty-four were
P-solubilzers, forty-three were siderophore producers and sixty were HCN producers.
Twelve showed antagonism against Rhizoctonia solani, thirteen against Fusarium
oxysporum andfifteen against Pythium sp. The maximum P-solubilization (184.63
μg/ml) was recorded for isolate BiA3 and maximum IAA production (84.56 μg/ml)
was noted for isolate MaA1. Maximum siderophore production with zone size of 12
mm was recorded with the isolate MaA1 on CAS medium in A. lebbeck. In L.
leucocephala, the maximum P-solubilization (180.15 μg/ml) was recorded for isolate
SoL9 and maximum IAA production (86.28 μg/ml) was noted for isolate SiL7. Genetic
diversity of 33 most potential isolates of A. lebbeck and L. leucocephalawas studied
using restriction enzymes AluI and MspI by ARDRA. 33 isolates were grouped into six
and seven major phylotypes, respectively. Among 33 sequenced isolates, 15 isolates
were Rhizobium, 2 isolates were Agrobacterium and 16 isolates were from another
genus (Bacillus, Arthrobacter, Paenibacillus, Serratia and Glutamicibacter).
Inoculation with PGP rhizobia in six different treatment combination showed that the
application of R. leguminosarum BiA3 and R. jaguaris HrL2 had significant increase in
shoot height, root length, root and shoot biomass, number of nodules, leghemoglobin
content and nitrogenase activity over uninoculated control