Staurosporine from the endophytic Streptomyces sp. strain CNS-42 acts as a potential biocontrol agent and growth elicitor in cucumber

Abstract

Chinese medicinal plants and their surrounding rhizospheric soil serve as promising sources of actinobacteria. A total of 180 actinobacteria strains were isolated from the rhizosphere soil, leaves, stems, and roots of nine selected plants and have been identified as potential biocontrol agents against Fusarium oxysporum f. sp. cucumerinum. An endophytic strain CNS-42 isolated from Alisma orientale showed the largest zone of inhibition demonstrating a potent effect against F. oxysporum f. sp. cucumerinum and a broad antimicrobial activity against bacteria, yeasts, and other pathogenic fungi. The in vivo biocontrol assays showed that the disease severity index was significantly reduced (P < 0.05), and plant shoot fresh weight and height increased greatly (P < 0.05) in plantlets treated with strain CNS-42 compared to the negative control. This isolate was identified as Streptomyces sp. based on cultural, physiological, morphological characteristics, and 16S rRNA gene analysis. Further bioassay-guided isolation and purification revealed that staurosporine was responsible for its antifungal and plant growth promoting activities and the latter property of staurosporine is reported for the first time. The in vivo assay was further performed and indicated that staurosporine showed good growth promoting effect on the plant shoot biomass of cucumber. This is the first critical evidence identifying CNS-42 as a biocontrol agent for the soil borne pathogen, F. oxysporum f. sp. cucumerinum.

Synergistic antifungal indolecarbazoles from Streptomyces sp. CNS-42 associated with traditional Chinese medicine Alisma orientale

“…10,11 Staurosporines (1-4) showed typical UV-visible spectra similar to those of known indolecarbazoles (supporting information). Figure S2).…”

“…10 In our lab, the well-developed HTSS platform has highlighted two significant products, beauvericin and avermectin (Supplementary Table S2), which showed outstanding synergistic activities in combination with a low dosage of KTC against fungal pathogens in vitro. In this study, we report two more molecules 1 and 2 identified with good synergistic antifungal activity.…”

Screening endophytic actinobacteria with potential antifungal activity against Bipolaris sorokiniana and growth promotion of wheat seedlings

“…and P. parasitica were inhibited by 47.5, 55.0, 62.5, 77.5 and 90% of the isolates, respectively. Li et al (2014) isolated an endophytic Streptomyces strain CNS-42 isolated from Alisma orientale and showed a potent effect against F. oxysporum f. sp. cucumerinum and a broad antimicrobial activity against bacteria, yeasts and other pathogenic fungi.…”

Molecules to Ecosystems: Actinomycete Natural Products In situ

“…Root-colonizing Streptomyces have been found to produce a number of antifungal and antimicrobial compounds in situ such as staurosporine, 3-acetonylidene-7-prenylindolin-2-one, diastaphenazine, and antimycin A18 (Yan et al, 2010; Li et al, 2014, 2015; Zhang et al, 2014). These in situ analyses offer a critical lens for beginning to understand bioactive compound production in the natural context of the rhizosphere.…”

“…By in large, this association is beneficial for plants as they may receive multiple chemical inputs from actinobacteria, including siderophores, phytohormones, antibiotics, and antifungals that inhibit potential pathogens (Solans et al, 2011; Rungin et al, 2012; Harikrishnan et al, 2014; Li et al, 2014; Zhang et al, 2014). Most studies have examined actinomycete/plant relationships in the context of food crops, some of which are grasses such as wheat, sorghum, rye, maize, and rice (Bressan, 2003; Merzaeva and Shirokikh, 2010; Harikrishnan et al, 2014; Toumatia et al, 2016).…”