The elusive bio-stimulatory function of Cladophialophora chaetospira SK51 to alleviate Fusarium wilt of strawberry

Abstract

Abstract The highly virulent Fusarium oxysporum formae speciales (f.sp.) fragaria causes Fusarium wilt and significant losses in the strawberry agroindustry. The effective control strategies for this phytopathogen have yet to be developed. We aimed to evaluate the bioefficacy of root-colonizer dark septate endophytic fungi (DSEs) in controlling Fusarium wilt in simultaneous with biostimulation activities. Three out of nineteen tested isolates were selected because of their superior bioefficacy in regulating disease suppression and growth promotion. Notably, the highest level of disease suppression was marked at 90.48%, followed by 85.71% and 61.90% with the inoculation of these three selected isolates i.e., SK51, SK47, and SK48, respectively. The fungal isolates were identified based on partial SSU, LSU, and ITS as DSE fungus Cladophialophora chaetospira strain SK51, Exophiala sp. strain SK47, and E. pisciphila strain SK48. Our findings showed that C. chaetospira SK51 exhibited significant potential in promoting plant growth and suppressing diseases. It significantly enhanced various plant growth factors, such as the total plant biomass, the content of chlorophyll (SPAD), the formation of flower buds, and the development of fruits compared to both non-inoculated control and the other two DSE-inoculated plants. Our study provides new findings and perspectives on the use of the DSE, particularly C. chaetospira SK51 as a bioprotectant and biostimulant for enhancing the development, flower bud formation, and fruit development in strawberry plants.