International Journal of Advance Agricultural Research
ISSN: 2053-1265
Vol. 11(3), pp. 16-26, June 2023
doi.org/10.33500/ijaar.2023.11.003

Appraisement of antimicrobial potential of organic extracts of Trichoderma virens and Trichoderma asperellum against Phytophthora colocasiae, the causal agent of taro leaf blight

Moïse Ntah A Ayong¹, Henri Tibo Ambata Ambata¹, Marie Ampère Boat Bedine², Eveline Siebatcheu¹, Olivier Youassi Youassi¹, Severin Nguemezi Tchameni¹*, Modeste Lambert Sameza¹ and Jean Duplex Wansi³

¹Laboratory of Biochemistry, Department of Biochemistry, Faculty of Sciences, University of Douala, Cameroon, P. O. Box 24 157 Douala, Cameroon.
²Phytopathology and Agricultural Zoology Research Unit, Department of Agriculture, Faculty of Agronomy and Agronomic Sciences, University of Dschang, P. O. Box 96, Dschang, Cameroon.
³Laboratory of Chemistry, Department of Chemistry, Faculty of Sciences, University of Douala, Cameroon, P. O. Box 24 157 Douala, Cameroon.

*To whom correspondence should be addressed. E-mail: tchameni1@yahoo.fr, stchameni@gmail.com.

Received 18 April, 2023; Received in revised form 7 May, 2023; Accepted 12 May, 2023.

Abstract

Keywords:
Trichoderma, Phytophthora colocasiae, Organic extract, Bioactivity, Taro leaf blight.

This work aimed to evaluate the bioactive potential of organic (ethyl acetate) crude extracts from two Trichoderma strains against Phytophthora colocasiae, the causal agent of taro leaf blight. Trichoderma sp. were isolated from taro rhizosphere by the soil dilution method and identified by amplifying the sequences of ITS1 and ITS4. Organic extracts were obtained from liquid fermentation, and the secondary metabolites were quantified using a spectrophotometer. Antimicrobial activities of the extracts were evaluated on mycelial growth, zoospores, and sporangia germination, as well as the reduction of leaf necrosis on detached taro leaves. The results obtained show that molecular typing identified antagonist fungal isolates as Trichoderma virens (MN833411.1) and Trichoderma asperellum (MN452804.1) with 99.2% and 100% similarity, respectively. All the organic extracts contained high amounts of polyphenols, flavonoids, tannins, and significantly inhibited the mycelial growth, zoospores, and sporangia germination of P. colocasiae. The total inhibition of mycelial growth was obtained at 100 µg/plug and 200 µg/plug respectively, for organic extracts of T. virens and T. asperellum. For both organic extracts, at 4 µg/plug, total inhibition of the zoospores’ germinations were obtained while at 2 µg/plug, we observed total inhibition of sporangia germination. At 800 µg/mL, these organic extracts also significantly reduced necrosis development on detached taro leaves, both for healing (55.35 and 37.92% respectively, for extracts of T. virens and T. asperellum) and preventive testing (55.35 and 37.92% respectively, for the extracts of T. virens and T. asperellum). This findings suggest that organic extracts from T. virens and T. asperellum could be used in an eco-friendly way to manage taro leaf blight.