At last decade Trichoderma sp. has been used as biocontrol agent as it produces a plethora of inhibitory secondary metabolites with biological activities, which includes volatile, non volatile and diffusible types. The process of invasion and infection of the ground nuts (Arachis hypogaea L.) by Aspergillus species and subsequent production of aflatoxin is quite complex, but in such situation, the biological control method has been successfully utilized. In the present study 10 species of Aspergilli were isolated and purified from the rhizosphere of infected A. hypogaea. Finally the selection of aflatoxigenic A. flavus and A. parasiticus were done assuming their higher aflatoxin production observed at 365nm under UV on coconut agar medium.Similarly fourspecies of Trichoderma viz. T. viride, T. harzanium, T. flavofuscum and T. virens were screened for their antagonistic properties based on co-culture (Dual culture, pathogen at centre and pathogen at periphery techniques) and inverted colonyplate technique against selected seven Aspergillus species. It has been observed that T. virens and T. harzanium were more effective in their action of diffusible metabolites, while, T. flavofuscum shows the significant results in case of volatile metabolites against aflatoxin producing Aspergillus species. In the co-culture system for bioremediation of aflatoxins, T. harzanium superiorly control the growth of A. flavus (20.94%) with aflatoxin B1 (75%).While in case with A. parasiticus inhibition observed as growth (47.91%), Aflatoxin-B1 (86.66%) and G1 (77.77%). The integrated management of aflatoxin was established in field experiment. It has been found out that the use of Trichoderma culture for twice, 1) in soil and 2) during flowering could provide a better control of A. flavus as T. harzanium reduces B1 concentration from31.35068 to 4.8274176 µg/100g) and A. parasiticus (from 10.33538 to 1.15804 µg/100g) as analysed by UV and HPLC technique. The trichodermal metabolite production was carried out on the PDA fermentation medium for three weeks at 28°C. The fungal metabolites extracted using the solvent partition fractionation method. The extract was dried and separated by optimizing solvent system for TLC. The antifungal activities of purified metabolites were performed by TLC bioautography method against A. flavus and A. parasiticus. The bioactive band was purified andcharacterized by UV, HPLC and LC-MS, showing harzianic acid and 6-n-pentyl pyrone as antifungal metabolites.
Tạp chí: Kỷ yếu hội thảo khoa học quản lý dịch hại tổng hợp cây trồng theo hướng hữu cơ sinh học trong phát triển nông nghiệp xanh, . Trường Cán Bộ Quản lý Nông Nghiệp và PTNN 2. Thành Phố HCM
Tạp chí khoa học Trường Đại học Cần Thơ
Lầu 4, Nhà Điều Hành, Khu II, đường 3/2, P. Xuân Khánh, Q. Ninh Kiều, TP. Cần Thơ
Điện thoại: (0292) 3 872 157; Email: tapchidhct@ctu.edu.vn
Chương trình chạy tốt nhất trên trình duyệt IE 9+ & FF 16+, độ phân giải màn hình 1024x768 trở lên