A Novel Antifungal Actinomycete Streptomyces sp. Strain H3-2 Effectively Controls Banana Fusarium Wilt

Abstract

Banana Fusarium wilt disease caused by Fusarium oxyspoum f. sp. cubense (Foc) seriously threatens the banana industry. Foc tropical race 4 (Foc TR4) can infect almost all banana cultivars. Compared with traditional physical and chemical practices, biocontrol strategy using beneficial microbes is considered as an environmentally sound option to manage fungal disease. In this study, a strain, H3-2, isolated from a non-infected banana orchard, exhibited high antifungal activity against Foc TR4. According to its morphological, physiological, and biochemical characteristics, the strain H3-2 was identified as Streptomyces sp. and convinced by the polymorphic phylogenic analysis of 16S rRNA sequences. Extracts of the strain H3-2 suppressed the growth and spore germination of Foc TR4 in vitro by destroying cell membrane integrity and mycelial ultrastructure. Notably, the strain and its extracts showed broad-spectrum antifungal activity against the selected seven fungal phytopathogens. Fourteen chemical compounds in the extracts were identified by gas chromatography–mass spectrometer (GC-MS), primarily phenolic compounds. Additional pot inoculation experiment demonstrated that the fermentation broth of the strain H3-2 promoted the growth of banana seedlings by efficiently inhibiting the spread of banana Fusarium wilt disease. This study demonstrated the potential application of the novel Streptomyces sp. H3-2 for the management of banana Fusarium wilt.

A Swamp Forest Streptomyces sp. KF15 with Broad Spectrum Antifungal Activity against Chilli Pathogens Exhibits Anticancer Activity on HeLa cell line

“…The results hinted at complete collapse and degeneration of spores due to decreased exopolysaccharide formation in outer membrane (Li et al 2021). Another study reported the morphology of treated hypha showing exfoliated akes, shrivelling, vacuolation and blistering; thickened cell wall and septum with partly ruptured cell membrane along with swollen cell nucleus was also observed (Zou et al 2021).…”

Discovery of Niphimycin C from Streptomyces yongxingensis sp. nov. as a Promising Agrochemical Fungicide for Controlling Banana Fusarium Wilt by Destroying the Mitochondrial Structure and Function

“…The PDA plates were incubated at 28 °C for 5 days. The inhibition rate (IR) was calculated according to Zou et al 10 Based on the inhibition rate against Foc TR4, an isolate, labeled as strain 2−11, with strong antifungal activity was selected for the following study. Twelve phytopathogenic fungi were chosen to further analyze the broad-spectrum antifungal activity of strain 2−11 (Table S1).…”

“…Effect of Niphimycin C on the Hyphal Morphology of Foc TR4. The hyphal morphology of Foc TR4 was determined according to Zou et al 10 Briefly, Foc TR4 was inoculated onto the PDA plate containing 2 × EC 50 of niphimycin C and incubated at 26 °C for 3 days. The control plate contained 10% (v/v) DMSO.…”

“…8,9 Nearly 80% of the antibiotics used in agriculture, industry, and medicine are produced by actino-mycetes, and 75% of them are from the genus Streptomyces. 10 Streptomyces produce several well-known antibiotics such as spectinomycin, nystatin, 6-prenylindole, salvianolic acid B, feigrisolide B, and oligomycin A. These antibiotics are the major fungicides for protecting plants from phytopathogenic fungi.…”

“…Actinomycetes are the most widely distributed microbes in nature. They can produce large amounts of bioactive compounds. , Nearly 80% of the antibiotics used in agriculture, industry, and medicine are produced by actinomycetes, and 75% of them are from the genus Streptomyces …”