Findings highlight the potential of indigenous rhizosphere microorganisms as biological control agents for the management of wheat root rot pathogens and identify the Bacillus strain showing the strongest growth-promoting effect.
Abstract
Abstract Soil-borne fungal pathogens significantly limit wheat production in Kazakhstan, particularly Fusarium solani (Mart.) Sacc. 1881 and Bipolaris sorokiniana (Sacc.) Shoemaker, 1959, which cause root rot and early seedling decline. This study aimed to isolate and characterize indigenous rhizosphere antagonists with biocontrol potential against these pathogens and to evaluate their effects on wheat seed germination and early growth. More than 20 microbial isolates were obtained from the rhizosphere of winter wheat. Two active antagonistic strains were selected by dual-culture assays: Bacillus sp. NK1 and Trichoderma harzianum S1. Inhibition zones against F. solani reached 23.75 ± 0.67 mm for NK1 and 32.89 ± 0.67 mm for S1. Cell-free culture supernatants significantly reduced mycelial growth and completely inhibited spore germination. Molecular identification based on 16S rRNA sequencing and TEF-1α/RPB2 analysis confirmed the taxonomic affiliation of both isolates. Seed treatment significantly improved germination (88%), root length, shoot length, and seedling vigor compared with untreated controls (P < 0.01). In pot experiments, both strains promoted biomass accumulation and improved seedling growth under pathogen pressure, with the Bacillus strain showing the strongest growth-promoting effect. Combined inoculation did not result in a synergistic response. These findings highlight the potential of indigenous rhizosphere microorganisms as biological control agents for the management of wheat root rot pathogens.
. Abstract: Root rot remains one of the most significant diseases of winter wheat ( Triticum aestivum L.) in Kazakhstan, resulting in substantial yield losses. This study aimed to isolate and identify rhizosphere microorganisms associated with winter wheat and evaluate their antagonistic activity against root rot pathogens in the Almaty region of Kazakhstan. In total, seven bacterial and fungal isolates, belonging to the genera Bacillus , Lysinibacillus, and Trichoderma, were identified. Strain K-C-24 showed 99.87% homology with Bacillus mojavensis . Trichoderma asperellum strains GL and 101 showed the highest antagonistic activity, effectively inhibiting the growth of all tested pathogens, with inhibition reaching zones up to 37 mm. Bacterial strain K-C-24 ( B. mojavensis ) was active against Bipolaris sorokiniana with an inhibition zone of 23.5±0.5 mm, and its culture filtrate showed a strong inhibitory effect on F. oxysporum (42±0.5 mm), but showed no activity against other pathogens. Other isolates showed no significant antagonistic activity. The greenhouse experiment demonstrated the lowest rates of damage to the roots of wheat seedlings infected by F. oxysporum when treated with a consortium of bacteria from the genera Bacillus and Lysinibacillus (Mix bac) and the strain T. asperellum GL. The obtained results confirm the potential of using local antagonist strains, especially T. asperellum, B. mojavensis, and a consortium of bacteria, Bacillus and Lysinibacillus (Mix bac) strains, for the development of environmentally safe biopreparations against root rot of winter wheat in the Almaty region of Kazakhstan.
N. Kuldybayev, A. Sadanov, A. Qairatova et al.· OnLine Journal of Biological...· 0 citations
Overall, in planta efficacy was highly variable compared to the strong in vitro inhibition, Nevertheless, selected commercial strains show clear potential to mitigate severe disease symptoms under high R. solani pressure.
F. Porsche, Marwin S. Nagel, Anja Frank et al.· Scientific Reports· 0 citations
Abstract Fusarium wilt of tomato, caused by Fusarium oxysporum f. sp. lycopersici, is a major constraint to global production, causing up to 80% yield loss under favourable conditions. Plant growth-promoting rhizobacteria (PGPR) offer an eco-friendly alternative for disease management through growth promotion and pathogen suppression. This study aimed to isolate and characterise PGPR from tomato rhizosphere soils across different agro-climatic zones of Assam and evaluate their antagonistic potential under in vitro and glasshouse conditions. A total of 216 isolates were obtained, of which six showed strong antifungal activity (64–83% inhibition) in dual culture assays. Glasshouse evaluation revealed significant reduction in disease incidence (64.80–80.73%) over control. Molecular identification classified these isolates into Bacillus, Pseudomonas, Clostridium, Lysinibacillus, and Achromobacter. Biochemical analyses confirmed production of indole acetic acid, ammonia, siderophores, and phosphate-solubilizing compounds. These results demonstrate the potential of indigenous PGPR isolates as promising biocontrol agents for suppressing Fusarium wilt of tomato under greenhouse conditions. However, field validation and experiments including pathogen-free PGPR treatments are required to distinguish direct plant growth promotion from disease suppression before practical application.
L. Giri, Daisy Senapoty, P. Kaman et al.· Archives of Phytopathology a...· 0 citations
Sustainable agriculture increasingly relies on harnessing the complex, multitrophic network within the soil phytobiome to combat soil-borne pathogens. This study highlights the diversity and functional potential of
Trichoderma
spp. isolates from rhizospheric soils in the Saurashtra region, Gujarat of 250 soil samples, one hundred distinct
Trichoderma
isolates were obtained and further screened for their antagonistic efficacy against three major soil-borne fungal pathogens:
Sclerotium
spp.,
Fusarium
spp. and
Macrophomina
spp. The
In vitro
assay found elite strains, particularly Tr79, Tr80 and Tr44, that consistently showed mycelial inhibition of up to 80%. Scanning electron microscopy (SEM) of Tr79 confirmed robust mycoparasitic interactions, including hyphal coiling and mycelial degradation. Molecular characterization using TEF1-
α
and RPB2 gene sequencing delineated these isolates into three clades:
T. harzianum
,
asperelloides
and
longibrachiatum
. Compatibility testing with 21 agrochemicals showed that isolates Tr79 and Tr80 were most resilient to most herbicides and insecticides, supporting their integration into integrated pest management. Field experiments with groundnut and chickpea showed that a split application of Tr79 enriched with Farmyard Manure (FYM) significantly improved germination and yield, boosting yield threefold compared with the control and reducing disease incidence to 10.15 and 17.63%, respectively. These findings highlight the potential of region-specific
Trichoderma
strains to enhance crop resilience and productivity through sustainable disease management. These findings are first regional Multilocus characterization from Saurashtra.
Dhruvi K. Suvagiya, Ramesh K. Kothari· Frontiers in Microbiology· 0 citations
The charcoal rot caused by Macrophomina phaseolina is the most virulent soil-borne disease in mulberry. Due to the issues of pollution, disparity in soil ecosystem along with possible risks to silkworms, the natural control method known as a promising technique for the management of root diseases. The objective of this study was to evaluate the antifungal efficacy of Plant Growth Promoting Rhizobacteria (PGPR) isolates against M. phaseolina. The charcoal rot causing pathogen, M. phaseolina was isolated from infected mulberry roots and its morphological and microscopical characters were observed. A total of 10 PGPR isolates were purified from healthy mulberry rhizosphere soil and identified isolates were belonging to the genera of Bacillus. The antifungal activity showed that BSSY9 isolate showed maximum growth inhibition of 58.5 % followed by BSKP3 isolate with 54.07%. Hence, thisisolates could be useful in developing an eco-friendly root rot management practices.
Maria Joncy, V. S· Journal of Science & Technol...· 0 citations
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