New seed coating containing Trichoderma viride with anti-pathogenic properties

BACKGROUND: To ensure food security in the face of climate change and the growing world population, multi-pronged measures should be taken. One promising approach uses plant growth-promoting fungi (PGPF), such as Trichoderma, to reduce the usage of agrochemicals and increase plant yield, stress tolerance, and nutritional value. However, large-scale applications of PGPF have been hampered by several constraints, and, consequently, usage on a large scale is still limited. Seed coating, a process that consists of covering seeds with low quantities of exogenous materials, is gaining attention as an efficient and feasible delivery system for PGPF. METHODS: We have designed a new seed coating composed of chitin, methylcellulose, and Trichoderma viride spores and assessed its effect on canola (Brassica napus L.) growth and development. For this purpose, we analyzed the antifungal activity of T. viride against common canola pathogenic fungi (Botrytis cinerea, Fusarium culmorum, and Colletotrichum sp.). Moreover, the effect of seed coating on germination ratio and seedling growth was evaluated. To verify the effect of seed coating on plant metabolism, we determined superoxide dismutase (SOD) activity and expression of the stress-related RSH (RelA/SpoT homologs). RESULTS: Our results showed that the T. viride strains used for seed coating significantly restricted the growth of all three pathogens, especially F. culmorum, for which the growth was inhibited by over 40%. Additionally, the new seed coating did not negatively affect the ability of the seeds to complete germination, increased seedling growth, and did not induce the plant stress response. To summarize, we have successfully developed a cost-effective and environmentally responsible seed coating, which will also be easy to exploit on an industrial scale.