Isolation and Identification Antagonistic Bacterium Paenibacillus tianmuensis YM002 against Acidovorax citrulli

Abstract

In this study, we aimed to screen antagonistic microorganisms against Acidovorax citrulli, the causal agent of bacterial fruit blotch, which is known to induce sever diseases in cucurbit crops. From 240 bacterial strains isolated, only one unknown bacterial isolate, named YM002, showed significant antagonistic activity against A. citrulli KACC17909. Further experiments revealed that YM002 shows antagonistic activity against all tested A. citrulli strains, including KACC17000, KACC17001 and KACC17005, to different degrees. The phylogenetic analysis of 16S rRNA sequences identified YM002 as Paenibacillus tianmuensis. Importantly, pretreatment of cucumber (Cucumis sativus) leaves with YM002 enhanced disease resistance as observed by significantly reduced necrotic symptom development and bacterial growth. YM002-induced resistance accompanied by enhanced expression of defense-related genes, such as PAL1, PR1-1a and CTR1. Importantly, culture filtrate of YM002 significantly suppressed biofilm formation and swimming motility of A. citrulli, which is indispensable for its full virulence. In addition to its antagonistic activity, YM002 showed a various plant growth promotion (PGP)-related traits, such as production of ammonia production, amylase production, ACC deaminase production, inodole-3-acetic acid production, extracellular protease production, siderophore production, and zinc solubilization activities. Indeed, treatment of cucumber roots with YM002 significantly enhanced plant growth parameters, such as fresh and dry weight of leaves or roots. This study suggests the potential of YM002 as an effective PGPR with biological control activity against Acidovorax citrulli in cucumber plants.

Phosphate solubilizing Pseudomonas and Bacillus combined with rock phosphates promoting tomato growth and reducing bacterial canker disease

“…We isolated 100 bacteria from tomato rhizosphere soil using King B medium. King B is a non-selective medium and hence may support the growth of bacteria, belonging to diverse taxa including Pseudomonas, Bacillus, and Paenibacillus (Nam et al, 2016;Bouizgarne et al, 2023;Koo et al, 2023). Furthermore, bacteria were subsequently screened for their ability to solubilize TCP on NBRIP agar medium.…”

Fertilising Maize with Bio-Based Mineral Fertilisers Gives Similar Growth to Conventional Fertilisers and Does Not Alter Soil Microbiome

“…Similarly, a cluster comprising Acidovorax, Phormidium, and Phormidesmis was specifically associated with the PA treatment. Acidovorax is known to harbour both PGPR and plant pathogenic species [64,65]; Phormidium and Phormidesmis are ubiquitous cyanobacteria found in various environments and sometimes used for plant growth promotion or soil remediation [66][67][68]. Additionally, we observed other beneficial microorganisms associated with specific treatments; e.g., Novihervaspirillum, a common soil genus, was present in the PKA, PD, and C+ treatments [69,70]; Olivibacter, frequently encountered in rhizosphere soil exhibiting PGPR traits [71,72], displayed elevated relative abundance in the PKA, PD, and C+ treatments; Bdellovibrio, a bacterial predator known to house PGPR and biocontrol species [73,74], was detected in the ST and C+ treatments and in lower proportions in PD; and Kocuria, recognised as a PGPR [75], was observed in the ST, PD, and C+ treatments.…”