| Endophytes mediate biological processes such as plant growth,enhancing plant stress resistance,and resistance to pests and diseases.They are ideal materials to become"plant vaccines"and reduce the application of chemical fertilizers and pesticides.The previous research of our group showed that an endophytic Fusarium lateritium isolated from Nothapodytes pittosporoides in Guizhou has the effects of promoting growth and disease resistance in potato.In this study,the tomato,which is also a Solanaceae crop,was used as a research vehicle to explore the effect of endophytic F.lateritium on tomato growth,development and resistance to stress diseases.In-depth study of the biological function of the necrosis factor in the interaction between endophytic fungi and tomato was carried out,which laid a theoretical foundation for revealing the interaction mechanism between endophytic fungi and plants.The main results are as follows:1.F.lateritium significantly promoted the growth and root development of"Micro Tom"tomato.After 50 days by soil drenching with conidial suspension,the tomato plant height was increased by 1.15 times compared with the control group;the contents of chlorophyll a and chlorophyll b were increased by 1.16 times and 1.47times compared with the control group,respectively;the root biomass was increased by 1.38 times compared with the control group;2.The role of tomato growth.F.lateritium enhanced the resistance to Fusarium wilt in tomato.The results of bioassays showed that the disease index of tomato f.wilt in the treatment group with F.lateritium(45.16%)decreased by about 30%compared with the control group(74.15%).3.F.lateritium mediated the expression of tomato PTI-related genes and phytohormones gene.After treatment with F.lateritium,it could affect the expression of tomato PTI marker genes and key genes of phytohormones to different degrees.4.F.lateritium colonized the tomato root system.Tomato roots were treated with1×10~7CFU/m L of GFP fluorescence labeled F.lateritium,and the tomato roots were observed 14 hours after treatment.GFP fluorescence labeled F.lateritium was found in the tomato roots.5.FlNIS1 had no significant effect on the strain morphology and characteristics of F.lateritium itself.By exploring the color,spore morphology,spore production and growth of the mutant and wild-type strains in liquid culture,it was found that FlNIS1didn’t affect the pigment deposition,spore morphological development and stress resistance of F.lateritium,but its spore production and spore early germination rate were significantly different from those of the wild type.6.FlNIS1 affected the colonization of tomato by F.lateritium.After mutating FlNIS1,the plant PTI response is significantly enhanced.It is speculated that the FlNIS1 gene plays a role in mediating plant-endophyte interactions and breaks FlNIS1Balanced gene expression exacerbates plant PTI responses and inhibits fungal colonization.The above results indicated that the endophytic F.lateritium could colonized on tomato roots and mediated tomato growth promotion and disease resistance,and an effector protein F1NIS1 could play a role in the interaction between F.lateritium and tomato. |
