Fig. 6

A hypothetical working process in cucumber plants with T. longibrachiatum H9 inoculation. LRRs as well as CDPKs and other elicitor-responsive proteins were induced in the Trichoderma H9-inoculated cucumber plants to deliver the signal of perception. Subsequently, MAPK cascades were activated to regulate diverse downstream signaling pathways. Furthermore, phytohormone synthesis and signaling (JA/ET and SA) were activated to translate Trichoderma-induced signaling into the activation of effective defense responses. Consequently, a whole array of defense/stress-related genes and proteins, e.g. a variety of detoxifying enzymes for ROS scavenging, were up-regulated, thus rendering the cucumber plants more resistant to subsequent B. cinerea infection. Along with other defense strategies, the production of secondary metabolites was also employed as an important plant defense strategy