Anti-Oomycete Activity and Pepper Root Colonization of Pseudomonas plecoglossicida YJR13 and Pseudomonas putida YJR92 against Phytophthora capsici

Abstract

Previously, <i>Pseudomonas plecoglossicida</i> YJR13 and <i>Pseudomonas putida</i> YJR92 from a sequential screening procedure were proven to effectively control Phytophthora blight caused by <i>Phytophthora capsici</i>. In this study, we further investigated the anti-oomycete activities of these strains against mycelial growth, zoospore germination, and germ tube elongation of <i>P. capsici</i>. We also investigated root colonization ability of the bacterial strains in square dishes, including cell motility (swimming and swarming motilities) and biofilm formation. Both strains significantly inhibited mycelial growth in liquid and solid V8 juice media and M9 minimal media, zoospore germination, and germ tube elongation compared with <i>Bacillus vallismortis</i> EXTN-1 (positive biocontrol strain), <i>Sphingomonas aquatilis</i> KU408 (negative biocontrol strain), and MgSO<sub>4</sub> solution (untreated control). In diluted (nutrient-deficient) V<sub>8</sub> juice broth, the tested strain populations were maintained at >10<sup>8</sup> cells/ml, simultaneously providing mycelial inhibitory activity. Additionally, these strains colonized pepper roots at a 10<sup>6</sup> cells/ml concentration for 7 days. The root colonization of the strains was supported by strong swimming and swarming activities, biofilm formation, and chemotactic activity towards exudate components (amino acids, organic acids, and sugars) of pepper roots. Collectively, these results suggest that strains YJR13 and YJR92 can effectively suppress Phytophthora blight of pepper through direct anti-oomycete activities against mycelial growth, zoospore germination and germ tube elongation. Bacterial colonization of pepper roots may be mediated by cell motility and biofilm formation together with chemotaxis to root exudates.

Pseudomonas plecoglossicida (NR_114226) as a novel biocontrol agent against Fusarium crown rot of wheat

“…(2023) reported that Pseudomonas plecoglossicida RGK exhibits the capacity for hydrogen cyanide (HCN) production. Volynchikova and Kim (2023) demonstrated that P. plecoglossicida suppressed Phytophtora capsici through inhibition of mycelial growth and zoospore germination on M9 minimal medium and V8 juice broth.…”

“…In vivo effect of antagonistic strains on disease severity (%). Fungi (Ali et al, 2020;Höfte, 2021;Kumari et al, 2020), the biocontrol activity of Pseudomonas plecoglossicida, examined in this study, have received limited attention concerning its interactions with plant and pathogen systems (Volynchikova & Kim, 2023). It was originally identified that as a causal agent of bacterial haemorrhagic ascites in ayu fish (Plecoglossus altivelis) (Nishimori et al, 2000), this species is recognized for its pathogenicity towards freshwater fishes such as the large yellow croaker (Pseudosciaena crocea), pejerrey (Odontesthes bonariensis) and rainbow trout (Oncorhynchus mykiss) (Huang et al, 2018).…”

From Lab to Field: Biofertilizers in the 21st Century

“…Barley [25] Plant growth promotion Triticum aestivum [56] Antimicrobial activity; plant growth promotion Capsicum annuum [57] Pseudomonas putida…”