Trichoderma asperellum GD040 upregulates defense-related genes and reduces lesion size in Coffea canephora leaves inoculated with Colletotrichum cairnsense

Coffee anthracnose is an important disease around the world, which has seriously affected the profits of coffee growers. This study firstly reported Colletotrichum cairnsense as a pathogen to cause coffee anthracnose, and screened Trichoderma asperellum GD040 with good antagonistic (inhibition rate was 88.41%) and mycoparasitism ability. Root irrigation with T. asperellum GD040 spore suspension reduces lesion size caused by C. cairnsense on coffee leaves. Transcriptomic analysis showed that the expression of 175 genes in T. asperellum GD040 treated coffee was up-regulated, including 73 disease-resistance genes involved in the plant-pathogen interaction pathway, phenylpropanes biosynthesis pathway and other pathways, respectively. Results from qRT-PCR analysis indicated that the expression levels of 16 key resistance genes (11 disease-resistance genes reported in Coffea canephora, 2 phenylalanine biosynthesis-related genes, ETR, PAL, and OPR3) and 3 growth hormone synthesisrelated genes (Pin-1, SUAR, and GAs-30-O) were up-regulated remarkably in coffee leaves treated by T. asperellum GD040, and were significantly higher than those in coffee leaves inoculated with C. cairnsense. Findings of this study revealed the antagonistic mode of T. asperellum GD040 against C. cairnsense and the mechanism of inducing host resistance in coffee against anthracnose at the molecular level, which laid the foundation for the development of multifunctional Trichoderma biological agents and their application in managing coffee anthracnose.

Automated summary

Coffee anthracnose is a worldwide disease that has adversely affected coffee growers' profits. This study identified Colletotrichum cairnsense as a pathogen causing coffee anthracnose and discovered Trichoderma asperellum GD040 as an effective antagonist with strong inhibition and mycoparasitism abilities. The application of T. asperellum GD040 spore suspension through root irrigation effectively reduced lesion size on coffee leaves caused by C. cairnsense. Transcriptomic analysis revealed the up-regulation of 175 genes, including disease-resistance genes and genes associated with pathways such as plant-pathogen interaction and phenylpropanes biosynthesis, in coffee treated with T. asperellum GD040. Furthermore, qRT-PCR analysis demonstrated the significant up-regulation of key resistance genes and growth hormone synthesis-related genes in coffee leaves treated with T. asperellum GD040, indicating its potential for inducing host resistance against anthracnose. These findings provide valuable insights into the antagonistic mode and molecular mechanisms underlying Trichoderma-mediated control of coffee anthracnose.