Application Effects of Glomus intraradices and Trichoderma sp on Peroxidases Activities, Synthesis of Phenolic Compounds and Control of Anthracnose in Cassava (Manihot esculenta Crantz) Plants

Abstract

Cassava (Manihot esculenta Crantz) is a very important food in tropical countries. It is the second most consumed tuberous food crop after yam in Côte d’Ivoire. Grown for its tuberous roots and leaves, it contributes to food security and is a source of income for farmers. However, its cultivation faces pressure from pests and diseases (anthracnose) aggravated by soil infertility. This study was conducted to evaluate the application effects of Glomus intraradices (Gl.intr.) and Trichoderma sp (Tri.sp) on peroxidases activities, phenolic compounds synthesis and anthracnose control in cassava. Two cassava cultivars, YACE and TMS30572, were grown in greenhouses and in the field with Gl.intr and Tri.sp treatments at sowing. These fungi were applied individually and in combination (Gl.intr+Tri.sp). In greenhouses, Gl.intr and Tri.sp-treated plants were inoculated with the pathogen Colletotrichum gloeosporioides 48 days after sowing. The results showed that in each cassava cultivar, the mycorrhization intensity (I) was statistically not different (p>0.05) for Gl.intr and Gl.intr+Tri.sp treatments. The mycorrhization frequency (F) varied in the same cassava cultivar, i.e., 28.34 and 34.33% respectively for Gl.intr and Gl.intr+Tri.sp in YACE, and 37.81 and 41.66% for TMS30572. Regarding anthracnose symptoms, the necrotic area and the distance travelled by C. gloeosporioides in infected plants were reduced from 3.65 to 1.87 and from 10.25 to 8.98 respectively in treated plants. The quantity of total phenols and peroxidases activities increased from 1.58 to 3.17 times in plants treated with Gl.intr and Tri.sp, depending on the organs and cultivars of cassava compared to control plants. The application of Gl.intr and Tri.sp would play a role in the resistance of cassava to anthracnose.