Associated bacteria of different life stages of Meloidogyne incognita using pyrosequencing-based analysis
Yi Cao1,2, Baoyu Tian3, Xinglai Ji1
1Key Laboratory for Conservation and Utilization of Bio-resource, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China.
Abstract:
The root knot nematode (RKN), Meloidogyne incognita, belongs to the most damaging plant pathogens worldwide, and is able to infect almost all cultivated plants, like tomato. Recent research supports the hypothesis that bacteria often associated with plant-parasitic nematodes, function as nematode parasites, symbionts, or commensal organisms etc. In this study, we explored the bacterial consortia associated with M. incognita at different developmental stages, including egg mass, adult female and second-stage juvenile using the pyrosequencing approach. The results showed that Proteobacteria, with a proportion of 71-84%, is the most abundant phylum associated with M. incognita in infected tomato roots, followed by Actinobacteria, Bacteroidetes, Firmicutes etc. Egg mass, female and second-stage juvenile of M. incognita harbored a core microbiome with minor difference in communities and diversities. Several bacteria genera identified in M. incognita are recognized cellulosic microorganisms, pathogenic bacteria, nitrogen-fixing bacteria and antagonists to M. incognita. Some genera previously identified in other plant-parasitic nematodes were also found in tomato RKNs. The potential biological control microorganisms, including the known bacterial pathogens and nematode antagonists, such as Actinomycetes and Pseudomonas, showed the largest diversity and proportion in egg mass, and dramatically decreased in second-stage juvenile and female of M. incognita. This is the first comprehensive report of bacterial flora associated with the RKN identified by pyrosequencing-based analysis. The results provide valuable information for understanding nematode-microbiota interactions and may be helpful in the development of novel nematode-control strategies.
Insights
Root knot nematodes (RKNs) associate with diverse bacteria, primarily Proteobacteria. This study identified potential biological control agents within these bacterial communities, offering insights for nematode management strategies.
Area of Science:
- Microbial Ecology
- Plant Pathology
- Nematology
Background:
- Root knot nematodes (RKNs) are significant global plant pathogens, particularly affecting crops like tomatoes.
- Bacteria associated with plant-parasitic nematodes may act as parasites, symbionts, or commensals, influencing nematode biology.
- Understanding these nematode-microbiota interactions is crucial for developing sustainable agricultural practices.
Purpose of the Study:
- To comprehensively characterize the bacterial consortia associated with the root knot nematode, *Meloidogyne incognita*.
- To investigate bacterial communities across different developmental stages of *M. incognita* (egg mass, adult female, juvenile).
- To identify potential biological control microorganisms within the RKN microbiome for novel nematode management strategies.
Main Methods:
- Utilized pyrosequencing to analyze bacterial communities associated with *M. incognita*.
- Sampled bacterial flora from egg masses, adult females, and second-stage juveniles of RKNs in infected tomato roots.
- Bioinformatic analysis to determine bacterial phyla, genera, diversity, and functional roles.
Main Results:
- Proteobacteria (71-84%) was the dominant phylum, followed by Actinobacteria, Bacteroidetes, and Firmicutes.
- A core microbiome was present across all developmental stages, with minor variations in community composition and diversity.
- Identified bacteria genera with roles in cellulose degradation, pathogenicity, nitrogen fixation, and antagonism towards RKNs.
- Potential biological control agents (e.g., Actinomycetes, *Pseudomonas*) were most abundant in egg masses and decreased in later stages.
Conclusions:
- This study provides the first comprehensive pyrosequencing-based report on the bacterial flora associated with *Meloidogyne incognita*.
- The identified bacterial communities offer valuable insights into nematode-microbiota interactions.
- Findings support the potential development of novel, biologically-based strategies for managing RKNs.
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