Identification and molecular characterization of root nodule microsymbiont of Trigonella foenum-graecum L. growing in different soils from Western Rajasthan, India

Abstract

Aim : Methodology :Results : Interpretation :To identify and characterize N fixing root nodule bacteria (RNB) of (TFG) growing in soils collected from different districts of Western Rajasthan.Selected RNB strains were characterised phenotypically and molecular phylogeny was studied using their 16S rRNAand symbiosis-related gene sequences.The 31 selected RNB strains formed three groups on the basis of colony characteristics. The TFG-RNB strains showed metabolic diversity in terms of carbon utilization and intrinsic antibiotic resistance, with few strains showing NaCl tolerance up to 4% and growth on a wide range of pH (4-11). In 16S rRNA gene phylogeny six (TFG22, TFG33, TFG53, TFG59, TFG64 and TFG66) selected strains clustered in a novel clade close to type strains and forming two distinct 16S rRNA types. The symbiotic ( and ) and 16S rRNA phylogenies of TFGstrains were in congruence. The genes of TFG strains have intermediate sequences diversified from closely related and which indicates their evolution through horizontal gene transfer.Nitrogen fixing TFGstrains isolated from Western Rajasthan are potentially novel and showing plant growth promoting activity therefore can be used as inoculants in agricultural fields of semi-arid regions. Trigonella foenum-graecum

Phylogenetic diversity and plant growth-promoting activities of rhizobia nodulating fenugreek (Trigonella foenum-graecumLinn.) cultivated in different agroclimatic regions of India

“…meliloti in the western plateau and hill region. A recent study on fenugreek rhizobia from western Rajasthan also showed the presence of two unique 16S rRNA gene types, which are different from the type strains of E. meliloti and E. medicae (Gaur et al 2018). In addition to 16S rRNA gene phylogeny, the fenugreek rhizobia were placed in the clusters with the type strain of E. meliloti in phylogenies based on concatenated sequences of housekeeping genes, as well as the nodC and nifH genes.…”

“…A phylogeny based on nifH showed that the sequence type found in the western plateau and hills region was similar to that of Ensifer sp. JNVU TFG64 isolated from Trigonella foenum-graecum sampled in the Thar Desert, India (Gaur et al 2018) (Fig. 4).…”

“…Later, R. tibeticum was reported for nodulation and nitrogen fixation in fenugreek grown under nickel (Ni) stress in Egypt (Abd-Alla et al 2014). With specific regard to India, a novel clade close to E. meliloti and E. medicae was reported from the root nodules of fenugreek sampled in different soils of western Rajasthan (Gaur et al 2018). In the present study, we aimed to decipher the spatial distribution pattern of fenugreek rhizobia in different agroclimatic regions of India using MALDI-TOF MS based identification and phylogenetic analyses based on 16S rRNA, housekeeping and symbiotic genes.…”

Evolution of novel strains of Ensifer nodulating the invasive legume Leucaena leucocephala (Lam.) de Wit in different climatic regions of India through lateral gene transfer

“…The temperature-related variables describe the thermal tolerance of the species, while the precipitation related variables describe the water availability. These variables are useful in summarizing the climatic niche of species (Rathi et al 2018) and modelling their potential distribution area (Adhikari et al 2015(Adhikari et al , 2019.…”

“…Hence, it offers an excellent opportunity to identify and characterize the N-fixing root nodule microsymbionts associated with Leucaena growing in Indian soils from different climatic zones which have so far not been properly investigated. The other objective was to determine if Leucaena can select native rhizobia from Indian soils and how its microsymbionts differ from those reported from arid and semi-arid regions, as well as other parts of India (Gehlot et al 2013;Tak et al 2016;Sankhla et al 2017;Choudhary et al 2017Choudhary et al , 2018Choudhary et al , 2020Ojha et al 2017;Rathi et al 2017Rathi et al , 2018Gaur et al 2018;Tak and Gehlot 2019;Chouhan et al 2020). Moreover, it would be interesting to establish if it carries its own rhizobial-symbionts of Neotropical origins like invasive Mimosa pudica in India (Gehlot et al 2013) and/or if it has developed compatibility with native Indian rhizobia.…”