Spore production in the solid-state fermentation of stevia residue by Trichoderma guizhouense and its effects on corn growth

摘要

Trichoderma is an important and widely used plant growth-promoting fungus(PGPF).In this study,stevia residue amended with amino acids hydrolyzed from animal carcasses was used for the production of Trichoderma guizhouense NJAU 4742 by solid-state fermentation,and then its potential to promote corn plant growth was evaluated in combination with chemical fertilizer(CF)or organic fertilizer(OF).The highest spore number of 7×10^(9)CFU g^(–1)fresh weight was obtained under the following optimal parameters:material ratio of 50%(stevia residue:rice bran=1:1),pH value of 3.0(amended with 6.67%amino acids),initial moisture content of 60%,inoculum size of 10%,material thickness of 3 cm and an incubation time of 4 days.The aboveground corn plant biomass obtained with T.guizhouense applied alone and with CF treatments were slightly higher than those of no fertilizer control and CF treatments,respectively.However,T.guizhouense applied with OF significantly(P<0.05)increased aboveground biomass compared to OF and yielded the highest aboveground biomass among all the treatments.Moreover,T.guizhouense applications primarily influenced the fungal bulk soil community composition,among which three OTUs(OTU_(2)and OTU_(9)classified as Chaetomium,and OTU_(4)classified as Trichoderma)were stimulated in both bulk and rhizosphere soil.Notably,a specific OTU_(3)(Phymatotrichopsis)was only stimulated by T.guizhouense applied with OF,possibly leading to high soil productivity.These results show that it is feasible to employ stevia residue in the eco-friendly fermentation of T.guizhouense,which is strongly suggested for enhancing OF applications.