Taxonomical, functional, and cytopathological characterization of Bacillus spp. from Lake Magadi, Kenya, against Rhizoctonia solani Kühn in Phaseolus vulgaris L

Abstract

A decline in common bean production and the ineffectiveness of synthetic chemical products in managing plant pathogens has led to exploiting Kenyan soda lakes as an alternative search for biocontrol agents. This study aimed to identify phylogenetically Bacillus spp. from Lake Magadi and their antagonistic activity against Rhizoctonia solani under in vitro and in vivo conditions. The 16 S ribosomal RNA (rRNA) subunit sequences of six bacterial strains isolated from Lake Magadi showed diversity similar to the Bacillus genus; Bacillus velezensis, Bacillus subtilis, and Bacillus pumilus. In vitro, antagonism showed varied mycelium inhibition rates of fungi in the coculture method. Enzymatic assays showed the varied ability of isolates to produce phosphatase, pectinase, chitinase, protease, indole‐3‐acetic acid (IAA), and hydrogen cyanide (HCD). The in vivo assay showed M09 (B. velezensis) with the lowest root mortality and incidence of postemergence wilt. Pre‐emergence wilt incidence was recorded as lowest in M10 (B. subtilis). Isolate M10 had the highest phenylalanine ammonia‐lyase (PAL) for defense enzymes, while polyphenol oxidase (PPO) and peroxidase were recorded as highest in M09. For the phenolic content, M10 recorded the highest phenolic content. In conclusion, Lake Magadi harbors Bacillus spp, which can be used as a potential biocontrol of R. solani.

Efficacy of endophytic bacteria as promising inducers for enhancing the immune responses in tomato plants and managing Rhizoctonia root-rot disease

“…Besides, phenolic chemicals were able to strengthen cellular membranes by restricting membrane flexibility, which lowers the ability of free radicals to cross membranes and causes membrane peroxidation 92 , 93 . Our results were supported by many previous findings 48 , 94 .…”

Biocontrol and Growth Promotion Potential of Bacillus subtilis CTXW 7-6-2 against Rhizoctonia solani that Causes Tobacco Target Spot Disease

“…In addition, members from the genus Bacillus produce siderophores, the extracellular lytic enzymes cellulase, phosphatase, pectinase, chitinase, and protease, indole-3-acetic acid, and hydrogen cyanide ( Alfiky et al 2022 ; Wekesa et al 2023 ), which promote plant growth. These enzymes’ significant functions are to promote plant root development and increase plant dry weight ( Liu et al 2019 ; Deng et al 2022 ).…”

Utilizing Two Populations Derived from Tropical Maize for Genome-Wide Association Analysis of Banded Leaf and Sheath Blight Resistance

“…The screening was performed to assess BLSB resistance levels when the temperature ranged between 20 and 25 • C, and high relative humidity (over 81%) prevailed in the summer in the YS region and in the winter in the JH region of Yunnan province. These conditions created a favorable environment for the growth and spread of Rhizoctonia solani [7,8].…”

“…Rhizoctonia solani can disrupt the vascular tissues of maize plants, impeding the normal transport of water and nutrients and resulting in a significant reduction in maize yield. This disease tends to thrive in warm and humid climatic conditions, especially when the temperature is maintained at 28 ± 2 • C and the relative humidity exceeds 88% [7,8].…”