Diversity of culturable methylotrophic bacteria in different genotypes of groundnut and their potential for plant growth promotion

Abstract

This study aimed at documenting the culturable methylotrophic bacterial diversity across different groundnut genotypes and evaluating their effect on the growth of groundnut. 80 methylotrophic bacterial isolates were obtained from the phyllosphere of 15 groundnut genotypes collected from Tamil Nadu, India. The bacterial isolates were identified through sequencing of the 16S rDNA and were tested for their plant growth-promoting properties. Groundnut seeds were inoculated with methylotrophic bacteria and their effect on growth was evaluated via in vitro and pot experiments. Molecular identification revealed that the isolates belonged to 30 different species. A higher diversity of methylotrophic bacteria at genus and species level was found in groundnut genotype TMV2. Shannon diversity index was the highest in genotype TMV7, followed by VRI2 and TMV2. Similarly, geographical location also influenced the diversity of methylotrophic bacteria. In vitro seed germination assay revealed that methylotrophic isolates enhanced root growth and improved formation of root hair. The radicle length of treated seeds ranged from 2.7 to 8.4 cm. A higher shoot length was observed in the plants from seeds treated with VRI8-A4 (27.3 cm), followed by TMV13-A1 (26.3 cm) and K-CO3-3 (23 cm). The findings of this study strongly suggest that beneficial methylotrophic bacteria associated with the phyllosphere of groundnut play a major role in regulating plant growth.

Comparative Analysis of two Methylobacterium spp. for Mitigating Moisture Stress Induced by PEG in Early Growth Stages of Tomato

“…The treated M. aminovorans exhibit maximum number of root hairs (450) followed by M. thiocyanatum (441) as compared to uninoculated control (430) presented in table 2. Similar results were found in the maximum number of root hairs were formed in treated Methylobacterium strains as compared to control (Krishnamoorthy et al, 2018). Infected root hairs of M. aminovorans and M. thiocyanatum appeared like root tip bulging and thick short root hair followed by uninoculated control resembles like long and slender root hairs.…”

Phyllospheric Microbiomes: Diversity, Ecological Significance, and Biotechnological Applications

“…Generally, the phyllosphere contains four major phyla of bacteria such as the Proteobacteria, Firmicutes, Bacteroides, and Actinobacteria (Kembel et al 2014;Durand et al 2018). Methylotrophic bacteria are predominant in phyllosphere which includes genera such as Methylobacterium, Methylophilus, Methylibium, Hyphomicrobium, Methylocella, Methylocapsa, and Methylocystis (Mizuno et al 2013;Iguchi et al 2013;Kwak et al 2014;Krishnamoorthy et al 2018). Methylobacterium and Sphingomonas are the predominant genera belonging to the class alphaproteobacteria reported in several plant phyllospheres (Delmotte et al 2009;Kumar et al 2019a).…”

“…VOGs-Volatile organic gases (Knief et al 2012;Jo et al 2015). Studies proved that the C1 metabolic epiphytic bacteria such as Methylobacterium extorquens, Methylobacterium radiotolerans, and Methylocystis use methanol and acetate as their carbon and energy source at the phyllosphere (Belova et al 2011;Verginer et al 2010;Iguchi et al 2013;Jo et al 2015;Iguchi et al 2015;Krishnamoorthy et al 2018). The Methylobacterium extorquens contains the methanol-dehydrogenase-like protein XoxF which is expressed during the colonization on Arabidopsis thaliana (Schmidt et al 2010).…”

“…The Methylobacterium extorquens contains the methanol-dehydrogenase-like protein XoxF which is expressed during the colonization on Arabidopsis thaliana (Schmidt et al 2010). Besides, chloromethane metabolism (cmu pathway) in methylotrophs has been identified from the surface leaves of A. thaliana harbor (Nadalig et al 2011;Krishnamoorthy et al 2018). Table 5.6 shows the various phyllosphere methanogenic bacteria and its metabolism.…”

Functional Signatures of the Epiphytic Prokaryotic Microbiome of Agaves and Cacti

“…This finding highlights the widespread presence and importance of Methylobacterium in the phyllosphere of most land plants. Moreover, members of this genus also exert positive effects on the health and growth of different plants (Hornschuh et al, 2002;Abanda-Nkpwatt et al, 2006;Hellmuth and Kutschera, 2008;Madhaiyan et al, 2009;Tani et al, 2012;Kwak et al, 2014;Madhaiyan and Poonguzhali, 2014;Krishnamoorthy et al, 2018). Contrary to native plants, in the phyllosphere of A. tequilana from Amatitan the main AAP bacteria were the genus Belnapia (Rhodospirillales) that has also been linked to AAP in desert microbial crusts (Csotonyi et al, 2010) and to growth promotion of A. thaliana (Camarena-Pozos et al, 2019).…”