Isolation and identification of Amycolatopsis sp. strain 1119 with potential to improve cucumber fruit yield and induce plant defense responses in commercial greenhouse

Abstract

Background and aimsThe application of chemical fungicides is the rst strategy to control plant fungal diseases. This approach is highly polluting for the environment and affects human health. Arti cial introduction of bene cial rhizobacteria into the soil can be an economical and practical way to control phytopathogenic fungi in commercial greenhouses. Here, we recount the travel of a rare Actinomycete (Amycolatopsis strain 1119) from a maize eld to a commercial cucumber greenhouse. Methods and resultsCulturable bacteria from rhizosphere and bulk soils of dicot and monocot crops were isolated and screened. About 20% of the representative colonies showed Actinomycetes appearance. 106 Actinomycetes that had antagonistic activity against Phytophthora capsici and were able to produce IAA were selected for further analysis. Two Streptomyces strains (432 and 615) and 2 Amycolatopsis strains (3513 and 1119) that showed a positive effect on plant growth in greenhouse conditions were selected to evaluate for biocontrol potential. Strains 432, 3513, 615 and 1119 controlled incidence of the damping-off by 65%, 42%, 83% and 100% respectively. Application of strain 1119 under commercial greenhouse conditions resulted in an increase in fruit yield (20%) and a decrease in fruit nitrate content (70%). Increased antioxidant enzymes activity and increased LOX and APX transcription and also, increased expression of two genes PR1-1a and GLU (SAR genes) showed that strain 1119 could induce both ISR and SAR in cucumber without pathogen exposure. ConclusionOur results demonstrate that the Amycolatopsis strain 1119, has a great potential to enter the market as a bio-stimulator.

Actinomycete Potential as Biocontrol Agent of Phytopathogenic Fungi: Mechanisms, Source, and Applications

“…Systemic acquired resistance (SAR) and induced systemic resistance (ISR) are two forms of induced resistance, characterized based on signaling pathways [ 30 ]. SAR stimulates a rapid response in the phytopathogens and actinomycetes, stimulating a special ISR state called “priming”, for faster and stronger defense responses [ 55 , 56 ]. Actinomycetes are capable of inducing defense responses in plants through the overproduction of: (1) enzymes related to defense, which strengthen the cell wall structure, avoiding the entrance of phytopathogenic fungi, their colonization toward the plant, and catalyzing phenolic compound oxidation to quinones that are toxic for fungi [ 29 ]; (2) proteins (PR) related to pathogenesis, such as chitinase hydrolytic enzymes, and β-1,3-glucanase that break the phytopathogenic fungi cell wall structure [ 57 ]; (3) phytoalexins, which are toxic for phytopathogenic fungi, inhibit germ tube elongation and growth, decrease mycelial growth and limit glucose absorption [ 30 , 58 ]; (4) lignification promotion that contributes to plant cell wall hardening [ 59 ]; and (5) callus formation induction that isolates stress (biotic and abiotic) in the tissue, locally, by depositing a physical barrier [ 56 , 60 ].…”

Commonly Used Engineered Nanomaterials Improve Soil Health via Suppressing Soil-Borne Fusarium and Positively Altering Soil Microbiome

“…A significant negative correlation between the RA of Acremonium and soil morbidity as well as pathogen abundance indicates a potential inhibitory effect of this group of organisms on disease incidence Paenibacillus and Mesorhizobium can improve plant nitrogen fixation capacity. , Additionally, certain bacteria such as Achromobacter and Amycolatopsis can improve plant resistance to pathogenic bacteria. , Pseudomonas promotes plant growth via inhibition of pathogenic microorganisms, synthesis of somatotropic hormones, and enhancement of plant disease resistance . Overall, our findings demonstrate that the addition of NMs could recruit beneficial microorganisms and subsequently modulate the microbial community against soil-borne pathogens.…”

“…70,71 Additionally, certain bacteria such as Achromobacter and Amycolatopsis can improve plant resistance to pathogenic bacteria. 72,73 Pseudomonas promotes plant growth via inhibition of pathogenic microorganisms, synthesis of somatotropic hormones, and enhancement of plant disease resistance. 74 Overall, our findings demonstrate that the addition of NMs could recruit beneficial microorganisms and subsequently modulate the microbial community against soil-borne pathogens.…”

Seasonal changes in the abundance Fusarium proliferatium, microbial endophytes and nutrient levels in the roots of hybrid bamboo Bambusa pervariabilis × Dendrocalamopsis grandis

“…( Siddiqui et al., 2001 ; Chattopadhyay et al., 2022 ) and Amycolatopsis sp. ( Alipour Kafi et al., 2021 ; Basavarajappa et al., 2023 ) have the potential to promote plant growth and biocontrol. The beneficial fungus Serendipita acts as a differential indicator of diseased plant roots ( Mohamed et al., 2020 ).…”