Efficient control of the fungal pathogens Colletotrichum gloeosporioides and Penicillium digitatum infecting citrus fruits by native soilborne Bacillus velezensis strains
Tao Xuan Vu,
Tram Bao Tran,
Minh Binh Tran,
Trang Thi Kim Do,
Linh Mai Do,
Mui Thi Dinh,
Hanh-Dung Thai,
Duc-Ngoc Pham,
Van-Tuan Tran
Affiliations
Tao Xuan Vu
Center for Experimental Biology, National Center for Technological Progress, Ministry of Science and Technology, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Viet Nam
Tram Bao Tran
Center for Experimental Biology, National Center for Technological Progress, Ministry of Science and Technology, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Viet Nam
Minh Binh Tran
Center for Experimental Biology, National Center for Technological Progress, Ministry of Science and Technology, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Viet Nam
Trang Thi Kim Do
Center for Experimental Biology, National Center for Technological Progress, Ministry of Science and Technology, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Viet Nam
Linh Mai Do
Center for Experimental Biology, National Center for Technological Progress, Ministry of Science and Technology, C6 Thanh Xuan Bac, Thanh Xuan, Hanoi, Viet Nam; Genomics Unit, National Key Laboratory of Enzyme and Protein Technology, University of Science, Vietnam National University, Hanoi (VNU), 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam
Mui Thi Dinh
Genomics Unit, National Key Laboratory of Enzyme and Protein Technology, University of Science, Vietnam National University, Hanoi (VNU), 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam; Bio-Agritech, Thuong Mo, Dan Phuong, Hanoi, Viet Nam
Hanh-Dung Thai
Genomics Unit, National Key Laboratory of Enzyme and Protein Technology, University of Science, Vietnam National University, Hanoi (VNU), 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam; Department of Microbiology, Faculty of Biology, University of Science, Vietnam National University, Hanoi (VNU), 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam
Duc-Ngoc Pham
Department of Microbiology, Faculty of Biology, University of Science, Vietnam National University, Hanoi (VNU), 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam
Van-Tuan Tran
Genomics Unit, National Key Laboratory of Enzyme and Protein Technology, University of Science, Vietnam National University, Hanoi (VNU), 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam; Department of Microbiology, Faculty of Biology, University of Science, Vietnam National University, Hanoi (VNU), 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam; Corresponding author. Genomics Unit, National Key Laboratory of Enzyme and Protein Technology, University of Science, Vietnam National University, Hanoi (VNU), 334 Nguyen Trai, Thanh Xuan, Hanoi, Viet Nam.
Destruction of citrus fruits by fungal pathogens during preharvest and postharvest stages can result in severe losses for the citrus industry. Antagonistic microorganisms used as biological agents to control citrus pathogens are considered alternatives to synthetic fungicides. In this study, we aimed to identify fungal pathogens causing dominant diseases on citrus fruits in a specialized citrus cultivation region of Vietnam and inspect soilborne Bacillus isolates with antifungal activity against these pathogens. Two fungal pathogens were characterized as Colletotrichum gloeosporioides and Penicillium digitatum based on morphological characteristics and ribosomal DNA internal transcribed spacer sequence analyses. Reinfection assays of orange fruits confirmed that C. gloeosporioides causes stem-end rot, and P. digitatum triggers green mold disease. By the heterologous expression of the green fluorescent protein (GFP) in C. gloeosporioides using Agrobacterium tumefaciens-mediated transformation, we could observe the fungal infection process of the citrus fruit stem-end rot caused by C. gloeosporioides for the first time. Furthermore, we isolated and selected two soilborne Bacillus strains with strong antagonistic activity for preventing the decay of citrus fruits by these pathogens. Molecular analyses of 16 S rRNA and gyrB genes showed that both isolates belong to B. velezensis. Antifungal activity assays indicated that bacterial culture suspensions could strongly inhibit C. gloeosporioides and P. digitatum, and shield orange fruits from the invasion of the pathogens. Our work provides a highly effective Bacillus-based preservative solution for combating the fungal pathogens C. gloeosporioides and P. digitatum to protect citrus fruits at the postharvest stages.
