title: 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.
authors.affiliation: Department of Microbiology, College of Resource and Environment, Sichuan Agricultural University, Chengdu, 611130, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Li
authors.forename: Pei
authors.initials: P
authors.lastname: Huang
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Lie
authors.initials: L
authors.lastname: Xiao
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Liu
authors.forename: Krishna
authors.initials: K
authors.lastname: Bolla
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Linyong
authors.initials: L
authors.lastname: Zheng
authors.forename: Bingcheng
authors.initials: B
authors.lastname: Gan
authors.forename: Xueting
authors.initials: X
authors.lastname: Liu
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000898:Antibiosis; D000935:Antifungal Agents / Q000302:isolation & purification / Q000494:pharmacology*; D018553:Cucumis sativus / Q000382:microbiology / Q000502:physiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005670:Fusarium / Q000187:drug effects / Q000254:growth & development; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010572:Pest Control, Biological / Q000379:methods; D063245:Plant Development; D010937:Plant Growth Regulators / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D018547:Plant Stems / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D019311:Staurosporine / Q000302:isolation & purification / Q000494:pharmacology*; D013302:Streptomyces / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D000935:Antifungal Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D010937:Plant Growth Regulators; D012336:RNA, Ribosomal, 16S; D019311:Staurosporine