Cloning And Function Analysis Of FHB Resistance-related Genes From Wheat

Fusarium head blight, caused primarily by Fusarium graminearum, is a destructive disease ofwheat throughout the world. FHB epidemics not only cause significant yield losses, but alsoreduce grain quality primarily. Deoxynivalenol (DON) produced by F. graminearum whichenhance the pathogen to spread could be converted into inactivating formation D3G by UDP-glycosyltransferases (UGTs). FHB resistance-related genes were selected according to thetranscript profile generated from a FHB-susceptible cultivar Apogee and its one near-isogenicline Apogee73S2with resistance to FHB. Two UGT genes and one EGL gene were cloned inthis study and their functions were analyzed. The main results are as follows:1. TaUGT4and TaUGT5were obtained by in silico cloning and RACE, respectively.TaUGT4, which was located on chromosome2D, encoded461amino acids protein.Subcellular localization of TaUGT4indicated that TaUGT4protein was localized incytoplasm. Both of TaUGT4and TaUGT5have PSPG-box motif at C-terminus.2. Both of TaUGT4and TaUGT5were obviously induced by F. g inoculation or DONtreatment which suggested that the two UGT genes involved in response to F. g inoculation.The expressions of the two UGT genes were also significantly induced by MeJA treatment,implying that JA signaling pathway might play important roles against F. g inoculation.3. The TaUGT5transgenic Arabidopsis showed enhanced tolerance against DON whichsuggested that TaUGT5had the ability to deactivate DON.4. The ability of resistance to FHB was enhanced in FHB-susceptible cultivar bytreatment with SA or MeJA, and the effect was more significant in wheat spikes treated byMeJA. This result also suggested that JA signaling pathway might play important roles inFHB resistance.5. The expression of TaEGL1was higher in FHB-resistant cultivar than that in FHB-susceptible cultivar. Leaf cells could be damaged by renatured TaEGL1produced byprokaryotic expression, which suggested that TaEGL1might participated in F. g inoculation.6. The leaves of FHB-susceptible cultivar exhibited high resistance to F. g by treating theseeding with SA before the first leaf stretching. On the contrary, The leaves of FHB-resistantcultivar showed more susceptible to F. g by treating the seeding with MeJA before the firstleaf stretching.In conclusion, we cloned two novel TaUGT genes and one TaEGL gene from wheat, andanalysed their sequence characteristics and expression patterns. Their functions were analyzedby genetic transformation using Arabidopsis and exogenous hormone regulation. The above works established a foundation for using these novel genes in wheat transformation andgenetic improvement.