A Nodulation-Proficient Nonrhizobial Inhabitant of Pueraria phaseoloides

Pueraria phaseoloides is a legume cover crop, found chiefly in the wet zone of Sri Lanka. Nitrogen fixation is performed by nodular inhabitants of this cover crop, comparable to the nodule-dwelling bacteria of most other legume plants. We isolated a bacterium (Sub1) from Pueraria phaseoloides, of co...

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Main Authors: W. M. M. Wedage, A. H. M. N. R. Aberathne, I. N. Harischandra, D. Gunawardana
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:The Scientific World Journal
Online Access:http://dx.doi.org/10.1155/2019/9782684
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author W. M. M. Wedage
A. H. M. N. R. Aberathne
I. N. Harischandra
D. Gunawardana
author_facet W. M. M. Wedage
A. H. M. N. R. Aberathne
I. N. Harischandra
D. Gunawardana
author_sort W. M. M. Wedage
collection DOAJ
description Pueraria phaseoloides is a legume cover crop, found chiefly in the wet zone of Sri Lanka. Nitrogen fixation is performed by nodular inhabitants of this cover crop, comparable to the nodule-dwelling bacteria of most other legume plants. We isolated a bacterium (Sub1) from Pueraria phaseoloides, of coccobacillus cell shape, that showed nodulation, when assessed by hydroponics, showing nodules as early as 3 weeks after reinfection. When a nifH fragment from the genome of this bacterium was amplified using a pair of nifH primers, it yielded an amplicon of 360 bp that, when sequenced, helped us identify the bacterium, as belonging to a species of Pseudacidovorax intermedius, at 99% sequence identity. When we constructed a phylogenetic tree with neighboring sequences, we encountered nifH sequences of Pseudacidovorax, forming a monophyletic cluster, which too contained a single Azospirillum species. The genus Pseudacidovorax is a bacterium that, so far, has not been associated with legume nodules. Sub1 secreted a pair of enzymes to the extracellular medium to degrade cellulose and milk proteins. The Sub1 bacterium showed biofilm formation and secreted into the extracellular medium, indole acetic acid. Sub1 also showed a “bulls eye” swarming pattern for the chemoattractant proline, while showing no significant chemotaxis movement, for naringenin, quercetin, and glutamate. Sub1 too possesses the basic genetic foundation (nifH and nifD) to produce a molybdenum-dependent nitrogenase enzyme. We finally show that this rare nonrhizobial bacterium is able to impact, positively, nodulation and shoot length of Pueraria plants, demonstrating that this beta-proteobacterium can abet the biological vigor of this legume cover crop.
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spelling doaj-art-e806654e07fd4e49b2beb70a60d61cb92025-02-03T06:06:19ZengWileyThe Scientific World Journal2356-61401537-744X2019-01-01201910.1155/2019/97826849782684A Nodulation-Proficient Nonrhizobial Inhabitant of Pueraria phaseoloidesW. M. M. Wedage0A. H. M. N. R. Aberathne1I. N. Harischandra2D. Gunawardana3Department of Botany, Faculty of Applied Sciences, University of Sri Jayewardenepura, Sri LankaDepartment of Botany, Faculty of Applied Sciences, University of Sri Jayewardenepura, Sri LankaCentre for Biotechnology, Department of Zoology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Sri LankaDepartment of Botany, Faculty of Applied Sciences, University of Sri Jayewardenepura, Sri LankaPueraria phaseoloides is a legume cover crop, found chiefly in the wet zone of Sri Lanka. Nitrogen fixation is performed by nodular inhabitants of this cover crop, comparable to the nodule-dwelling bacteria of most other legume plants. We isolated a bacterium (Sub1) from Pueraria phaseoloides, of coccobacillus cell shape, that showed nodulation, when assessed by hydroponics, showing nodules as early as 3 weeks after reinfection. When a nifH fragment from the genome of this bacterium was amplified using a pair of nifH primers, it yielded an amplicon of 360 bp that, when sequenced, helped us identify the bacterium, as belonging to a species of Pseudacidovorax intermedius, at 99% sequence identity. When we constructed a phylogenetic tree with neighboring sequences, we encountered nifH sequences of Pseudacidovorax, forming a monophyletic cluster, which too contained a single Azospirillum species. The genus Pseudacidovorax is a bacterium that, so far, has not been associated with legume nodules. Sub1 secreted a pair of enzymes to the extracellular medium to degrade cellulose and milk proteins. The Sub1 bacterium showed biofilm formation and secreted into the extracellular medium, indole acetic acid. Sub1 also showed a “bulls eye” swarming pattern for the chemoattractant proline, while showing no significant chemotaxis movement, for naringenin, quercetin, and glutamate. Sub1 too possesses the basic genetic foundation (nifH and nifD) to produce a molybdenum-dependent nitrogenase enzyme. We finally show that this rare nonrhizobial bacterium is able to impact, positively, nodulation and shoot length of Pueraria plants, demonstrating that this beta-proteobacterium can abet the biological vigor of this legume cover crop.http://dx.doi.org/10.1155/2019/9782684
spellingShingle W. M. M. Wedage
A. H. M. N. R. Aberathne
I. N. Harischandra
D. Gunawardana
A Nodulation-Proficient Nonrhizobial Inhabitant of Pueraria phaseoloides
The Scientific World Journal
title A Nodulation-Proficient Nonrhizobial Inhabitant of Pueraria phaseoloides
title_full A Nodulation-Proficient Nonrhizobial Inhabitant of Pueraria phaseoloides
title_fullStr A Nodulation-Proficient Nonrhizobial Inhabitant of Pueraria phaseoloides
title_full_unstemmed A Nodulation-Proficient Nonrhizobial Inhabitant of Pueraria phaseoloides
title_short A Nodulation-Proficient Nonrhizobial Inhabitant of Pueraria phaseoloides
title_sort nodulation proficient nonrhizobial inhabitant of pueraria phaseoloides
url http://dx.doi.org/10.1155/2019/9782684
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