The Nif3-Family Protein YqfO03 from Pseudomonas syringae MB03 Has Multiple Nematicidal Activities against Caenorhabditis elegans and Meloidogyne incognita.

Abdul Manan,Lin Li,Jin Fan,Zahoor Bazai,Huafu Yu

doi:10.3390/ijms19123915

Abstract

The nematicidal activity of the common plant-pathogenic bacterium Pseudomonas syringae against certain nematodes has been recently identified, but little is known about its virulence factors. In the current study, predictive analysis of nematode-virulent factors in the genome of a P. syringae wild-type strain MB03 revealed a variety of factors with the potential to be pathogenic against nematodes. One of these virulence factors that was predicted with a high score, namely, YqfO03, was a protein with structural domains that are similar to the Nif3 superfamily. This protein was expressed and purified in Escherichia coli, and was investigated for nematicidal properties against the model nematode Caenorhabditis elegans and an agriculturally important pest Meloidogyne incognita. Our results showed that YqfO03 exhibits lethal activity toward C. elegans and M. incognita worms, and it also caused detrimental effects on the growth, brood size, and motility of C. elegans worms. However, C. elegans worms were able to defend themselves against YqfO03 via a physical defense response by avoiding contact with the protein. Discovery of the diverse nematicidal activities of YqfO03 provides new knowledge on the biological function of a bacterial Nif3-family protein and insight into the potential of this protein as a specific means of controlling agricultural nematode pests.

Highlights

A variety of soil-borne nematodes can infect the plants and inflict serious damage to plant hosts
Our results showed that the Nif3-like protein from P. syringae had toxicity against C. elegans and M. incognita
NZ_LAGV01000012.1), which had a high score for predicted virulence, as the target gene to investigate the pathogenic effect on C. elegans worms

Summary

Introduction

A variety of soil-borne nematodes can infect the plants and inflict serious damage to plant hosts. Current efforts to protect crops from nematode infestation focus on environmentally safe products [6] In this respect, many nematicidal bacteria have shown usefulness in controlling the detrimental effects of certain nematode pathogens, including PPNs [7]. These bacteria include Pasteuria penetrans [8], Pseudomonas aeruginosa [9,10], Bacillus thuringiensis [11], Bacillus firmus [12], Paecilomyces lilacinus [13], Arthrobotrys oligospora [14], and Burkholderia cepacia [15], among the others These microorganisms affect nematodes via different mechanisms, such as parasitism and antibiotic production and by producing toxins or enzymes that impede plant-host recognition by the nematode [7]. Such mechanisms raise the possibility that nematicidal bacteria could be used to prevent the plant damage that is caused by PPNs [16,17]

Methods

Results

Conclusion