The Mechanisms And Effect Of Trichoderma Hamatum Against Root-knot Nematode

Plant parasitic nematodes with wide host range cause huge yields and economics losses around the world annually.One of the measures to prevent and control the root-knot nematode disease is to use the beneficial microorganisms.Trichoderma spp.are considered symbiotic as they help in biocontrol of root pathogens,promote growth and development and induce plant defense responses by several mechanisms.In order to study the endophytic activity of Trichoderma hamatum strain T21,GFP tagged T21 was constructed by PEG-mediated protoplast transformation.We choose stable fluorescence properties and genetic stability of gfp-tagged GFP_T21.There were no significant differences between the GFP_T21 and T21 in growth rate and in fungal control efficiency in pot experiment,which indicated that GFP_T21 provides an important material for studying the biocontrol mechanism of Trichoderma hamatum.The mechanism of T21 to control root-knot nematode showed that T21 had no effect on opportunistic egg parasitism,and the culture filtrate had no lethal effect on the root-knot nematode.The results of Trichoderma hamatum strain T21 against Meloidogyne incognita by split-root experiment showed that the average number of root galls per plant of CK treatment was 60.0,and the T21 treatment was 16.1,There was a significant difference between T21 and CK treatments(P <0.0001,?= 0.01).It is suggested that Trichoderma hamatum strain T21 shows control efficiency of root-knot nematode disease through triggering host defences.GFP_T21 can colonize the root of Arabidopsis thaliana,and the salicylic acid(SA)-impaired mutant sid2-2 of Arabidopsis thaliana has been successfully identified,which lays the foundation for the further research on the mechanism of T21 to control root-knot nematode disease.In order to explore the application potential of T21 against root-knot nematode disease,the bioorganic fertilizers and the 10% fosthiazate granules were as the fertilizer and chemical control,respectively,the treatment without any fertilizer and pesticide was as the negative control.Based on the experiments performed in pot,greenhouse and field,all treatments were analyzed by measuring the root-knot nematode disease index,cucumber yield,plant height and shoot fresh weight.The results showed that control efficiency of fosthiazate treatment was up to 89.2% and 61.3% in pot experiment and greenhouse experiment,respectively,which was significantly higher than T21 and JJF treatments;The control efficiency of T21 treatment was up to 37.5% and 31.0%,which was extremely higher than JJF treatment.In pot experiment?greenhouse plot and field trials,the yield increase of T21 treatment was 34.1%,29.4% and 68.0%,respectively.Therefore,Trichoderma hamatum strain T21 has great extend value in the prevention and control of root-knot nematode disease.Study in this paper reveals Trichoderma hamatum strain T21 induce systemic resistance to the root-knot nematode,which lays a fundation for the future study about the mechanism of T21 to control root-knot nematode disease.