Poor competitiveness of Bradyrhizobium in pigeon pea root colonisation in Indian soils

A - Papers appearing in refereed journals

Chalasani, D., Basu, A., Pullabhotla, S. V. S . R. N., Jorrin, B., Neal, A. L., Poole, P. S., Podile, A. R. and Tkacz, A. 2021. Poor competitiveness of Bradyrhizobium in pigeon pea root colonisation in Indian soils . Microbiome. 12 (4), pp. e00423-21. https://doi.org/10.1128/mBio.00423-21

AuthorsChalasani, D., Basu, A., Pullabhotla, S. V. S . R. N., Jorrin, B., Neal, A. L., Poole, P. S., Podile, A. R. and Tkacz, A.
Abstract

Background
Pigeon pea, a legume crop native to India, is the primary source of protein for more than a billion people in developing countries. The plant can form symbioses with N2-fixing bacteria, however reports of poor crop nodulation in agricultural soils abound. We report here study of the microbiota associated with pigeon pea, with a special focus on the symbiont population in different soils and vegetative and non-vegetative plant growth.

Results
Location with respect to the plant roots was determined to be the main factor controlling the microbiota followed by developmental stage and soil type. Plant genotype plays only a minor role. Pigeon pea roots have a reduced microbial diversity compared to the surrounding soil and select for Proteobacteria and especially for Rhizobium spp. during vegetative growth. While Bradyrhizobium, a native symbiont of pigeon pea, can be found associating with roots, its presence is dependent on plant variety and soil conditions. A combination of metagenomic survey, strain isolation and co-inoculation with nodule forming Bradyrhizobium spp. and non-N2 fixing Rhizobium spp. demonstrated that the latter is a much more successful coloniser of pigeon pea roots.

Conclusions
Poor nodulation of pigeon pea in Indian soils may be caused by a poor Bradyrhizobium competitiveness against non-nodulating root colonisers such as Rhizobium. Hence, inoculant strain selection of symbionts for pigeon pea should not only be based on their nitrogen fixation potential but more importantly on their competitiveness in agricultural soils.

KeywordsPigeon pea; India; Microbiome; Rhizosphere; Bradyrhizobium; Competition; Bacterial community; 16S rRNA; Gene amplification
Year of Publication2021
JournalMicrobiome
Journal citation12 (4), pp. e00423-21
Digital Object Identifier (DOI)https://doi.org/10.1128/mBio.00423-21
Open accessPublished as ‘gold’ (paid) open access
FunderThe British Council
Biotechnology and Biological Sciences Research Council
Funder project or codeBB/N013387/1
Publisher's version
Accepted author manuscript
Output statusE-publication ahead of print
Publication dates
Online06 Jul 2021
Publication process dates
Accepted03 Jun 2021
PublisherSpringer Nature

Permalink - https://repository.rothamsted.ac.uk/item/9833z/poor-competitiveness-of-bradyrhizobium-in-pigeon-pea-root-colonisation-in-indian-soils

2 total views
7 total downloads
2 views this month
4 downloads this month
Download files as zip