Streptomyces strains modulate dynamics of soil bacterial communities and their efficacy in disease suppression caused by Phytophthora capsici

Abstract

The responses of rhizosphere bacterial communities of Streptomyces (SS14 and IT20 stains) treated-pepper plants following inoculation by Phytophthora capsici (PC) was investigated using Illumina MiSeq sequencing. Distinct modulation of the bacteriome composition was found for PC samples with the highest relative abundance (RA) of Chitinophaga (22 ± 0.03%). The RA of several bacterial operational taxonomic units (OTUs) was affected and caused changes in alpha and beta-diversity measures. In IT20, the RA of Cyanobacteria was enriched compared to SS14 (72%) and control samples (47%). Phylotypes belonging to Devosia, Promicromonospora, Kribbella, Microbacterium, Amylocolatopsis, and Pseudomonas genera in the rhizosphere were positively responding against the pathogen. Our findings show that the phosphate solubilizing strain IT20 has higher microbial community responders than the melanin-producing strain SS14. Also, positive interactions were identified by comparing bacterial community profiles between treatments that might allow designing synthetic bio-inoculants to solve agronomic problems in an eco-friendly way.

Microbiome engineering and plant biostimulants for sustainable crop improvement and mitigation of biotic and abiotic stresses

“…Even though inoculating exogenous microorganisms may not directly promote plant growth, they could benefit the plants by recruiting other microbial species known for their plant growth-promoting abilities [14]. For example, the inoculation of Streptomyces rochei IT20 had resulted in a higher α-diversity of the rhizospheric bacterial community and a relatively high abundance of other prolific plant growth-promoting Actinobacteria [33]. Another strategy for altering the crop ecosystems is to selectively enrich the indigenous beneficial microbial populations and re-introduce them back to the microbial community [14].…”

Rhizosphere Microbiome of Forest Trees Determines Their Resistance to Soil-borne Pathogens

“…However, in the cedar rhizosphere, the content of cis-13-octadecenoic acid, octadecamethyl-cyclononasiloxane, 2,5-dimethyl-benzaldehyde, and octasiloxane were higher, which induced the enrichment of Saccharimonadales, uncultured family in Acidimicrobiia, uncultured family in Acidobacteriales, and Micropepsaceae with negative effects on pathogen suppression. This suggested that the bacterial composition of the tree rhizospheres induced by root exudates plays a mediating role in rhizosphere resistance (Trivedi et al 2017a;Abbasi et al 2021). The signi cant correlations between rhizosphere microbial diversity and tree root exudates further supported this bioactive effect on the rhizosphere microbiota for responding to pathogen stress (Yang et al 2014;Li et al 2019).…”

Advances in Soil Engineering: Sustainable Strategies for Rhizosphere and Bulk Soil Microbiome Enrichment

“…Multiple strains belonging to diverse bacterial phyla, and even some fungi have been described (see Table 2, Ref. [24,78,86,136,137]).…”

“…More recently, in a study testing the growth of wheat in Pythium-infested soils by adding specific Streptomyces and Paenibacillus strains, an additional increase of Pseudomonas in the plant roots was observed [24]. In fact, other Streptomyces strains (SS14 and IT20) were described as having activity against Phytophthora capsici, and promoting additional taxa that also had activity against the pathogen, such as phylotypes belonging to Devosia, Promicromonospora, Kribbella, Microbacterium, Amylocolatopsis, and Pseudomonas genera [137]. Yin and colleagues [155] described multiple strains with acitivity against Rhizoctonia solani AG8 and other diseases isolated after successive monocultures and application of AG8 in the soils.…”