The Study Of FHB Resistant Roles Of JA In Wheat

Fusarium head blight(FHB)is a major fungal disease on the spikes of wheat in the whole world which seriously affects its yield.As climate becoming warm,the incidence of scab in china is gradually spreading from south to north.So it is urgent to study the FHB disease.Materials that resistant to scab is extremely limited.Although a great deal of research on the FHB resistance mechanism have been conducted previously,but it is not clear yet due to its complexity.In this study,we selected the most representative scab resistance variety Sumai 3 as research material.First of all,measuring the hormones of spikeltes which is infected of Fusarium graminearum,and based on this,we explored the disease resistance spikelets related pathways and verified the key genes combination with molecular biology experiments.The main research contents are as follows:(1)In order to confirm whether JA can truly respond to FHB,we measure its content changes in Su3 when inoculated F.g.The JA level of glume and rachis were measured at 0h,12 h,24h,48 h,72h and 96 h after inoculation.The results indicate that: The JA content in the glume and rachis showed an upward trend at 0–12h days post inoculation(dpi),and reached the highest peak at 72 h,next it drops sharply.This shows that after the infection of wheat,the increase of hormone content has a close relationship with the disease resistance process.However,the different rising trend and the sharp decrease of JA content at 72 h may be related to the antagonistic effect of SA.However,it can be confirmed that JA plays an active role in the disease resistance of head blight.(2)In order to verify that JA is involve in resistance to scab,the treatment of exogenous hormones on wheat spike was carried out.The results show that both and MeJA could increase the resistance of wheat to FHB,while the JA treatment on resistance material can promote the incidence of FHB.It indicates that SA could enhance the scab resistance in spikes of wheat,while JA have different regulatory mechanisms in wheat spikes and in different materials.(3)In this test,exogenous hormones were used to explore the direct effect on FHB.It shown that both SA and MeJA can inhibit the growth of F.g.And MeJA can inhibit F.g significantly at concentration of 0.1mmol/L,and SA is 0.2mmol/L.(4)BSMV-VIGS system is used to silence the genes involved in JA signal pathways in wheat leaves and spikes,respectively.After silencing TaAOS,TaAOC and TaOPR3 genes,Sumai3 enhanced the sensitivity to F.g.(5)Transgenic TaAOS wheat by RNAi is used to identification the FHB resistance.The results shown that the susceptibility to scab will be increased when TaAOS gene is silenced.