Complete Genome of a Biocontrol Agent Effective Against Plant Pests and Diseases

Jenn Hoskins
8th June, 2024

Complete Genome of a Biocontrol Agent Effective Against Plant Pests and Diseases

Image Source: Natural Science News, 2024

Key Findings

  • Researchers in Brazil found that the bacterial strain Ag109, identified as Bacillus velezensis, can control major soil pathogens in soybean cultivation
  • Ag109 reduced populations of harmful nematodes by up to 69% and showed antifungal activity against several fungi, improving plant health and root mass
  • Genomic analysis of Ag109 revealed genes that produce beneficial compounds and promote plant growth, highlighting its potential as a multifunctional biocontrol agent
Soybean is the main oilseed cultivated worldwide, and Brazil stands as the largest producer and exporter. However, soybean production in Brazil faces significant challenges due to biotic factors, particularly soil-borne diseases that severely reduce yield and are difficult to manage. A recent study conducted by researchers at the Universidade Estadual de Londrina aimed to evaluate the potential of a bacterial strain, Ag109, as a biocontrol agent for various soil pathogens affecting soybean[1]. The study revealed that Ag109, identified as Bacillus velezensis, exhibits promising biocontrol properties against nematodes and fungi, which are major soil pathogens in soybean cultivation. Specifically, Ag109 showed effective control over the populations of two nematode species: Meloidogyne javanica and Pratylenchus brachyurus, reducing their populations by 69% and 45%, respectively. Additionally, the strain demonstrated antifungal activity against Macrophomia phaseolina, Rhizoctonia solani, and Sclerotinia sclerotiorum. For S. sclerotiorum, Ag109 increased the number of healthy plants and root dry mass compared to the control group. The researchers employed whole-genome sequencing of Ag109 to identify genes related to secondary metabolite production and plant growth promotion. The genomic analysis uncovered diverse clusters of genes that contribute to the biosynthesis of secondary metabolites and promote root growth, underscoring the strain's potential as a multifunctional microbial inoculant. This study builds on previous research in the field of soybean disease management. For instance, a comprehensive review of quantitative trait loci (QTLs), genes, and alleles conferring resistance to 28 important soybean diseases highlighted the significance of disease-resistant soybean varieties in ensuring sustainable production[2]. The integration of marker-assisted selection and genomic selection was emphasized as a successful method for rapidly incorporating disease resistance into improved soybean varieties. The discovery of Ag109 as a biocontrol agent aligns with these efforts by providing a biological solution to manage soil-borne diseases. Furthermore, the identification of various Rhizoctonia-like isolates in Brazilian soils, including Rhizoctonia solani, which caused varying degrees of root rot severity, underlines the importance of effective disease management strategies[3]. The prevalence of these pathogens in agricultural soils necessitates the development of robust biocontrol agents like Ag109 to mitigate their impact on soybean production. In another relevant study, the genetic basis of drought-responsive mechanisms in soybean was explored by evaluating gene expression patterns in two contrasting genotypes under water deficit conditions[4]. The identification of transcription factors from the AP2/EREBP and WRKY families associated with drought tolerance provides insight into the genetic factors that can enhance soybean resilience to environmental stressors. Although this study focused on drought tolerance, it complements the current research by highlighting the importance of genetic and biological approaches in improving soybean resilience to various biotic and abiotic stresses. In conclusion, the discovery of Bacillus velezensis strain Ag109 as a biocontrol agent offers a promising solution for managing soil-borne diseases in soybean cultivation. By effectively controlling nematode and fungal populations and promoting plant growth, Ag109 has the potential to enhance soybean yield and sustainability. This study, conducted by the Universidade Estadual de Londrina, adds to the growing body of research aimed at improving soybean production through innovative biological and genetic strategies.

GeneticsBiochemPlant Science

References

Main Study

1) Complete genome sequence of Bacillus velezensis strain Ag109, a biocontrol agent against plant-parasitic nematodes and Sclerotinia sclerotiorum

Published 7th June, 2024

https://doi.org/10.1186/s12866-024-03282-9

Related Studies

2) Breeding for disease resistance in soybean: a global perspective.

https://doi.org/10.1007/s00122-022-04101-3

3) Diversity and Pathogenicity of Rhizoctonia Species from the Brazilian Cerrado.

https://doi.org/10.1094/PDIS-05-17-0721-RE

4) Differential gene expression in response to water deficit in leaf and root tissues of soybean genotypes with contrasting tolerance profiles.

https://doi.org/10.1590/1678-4685-GMB-2018-0290


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