| Xanthomonas ourer proteins were primarily defined as extracellular proteins secreted by typelll secretion system(T3SS)in Xanthomonas oryzae pv.oryzae(Xoo)and oryzicola(Xoc).XopN is an effector from Xoo,but its fuction in PX099A strain is still unknow.In this study,the XopN gene knock-out mutant PX099A△XopN was generated by double crossover homologous-recombination,and then we constructed the complementation strain C-XopN.In this study,we detected the functions of PX099A△XopN through growth rates,pathogenicity to rice,hypersensitive response on tobacco.We discovered that PX099A△XopN grow slower than wild PX099A in NA medium.PX099A△XopN showed a short lesion length in some rice leaves such as IRBB13 and the difference depands on rice varieties.After a week past inoculation,PXO99A△XopN multiplication was slightly but significantly reduced as compared to the wild type PXO997A.The introduction of XopN coding sequence to PX099AAXopN could recover the deficience to PX099A:both growth rates and pathogenicity to rice.Hypersensitive response on tobacco was delayed by PX099A△XopAN compared to wild type PX099A.Riboflavin binding protein is a kind of protein that can combine with riboflavin.Recently we found that de novo expression of RfBP in transgenic Arabidopsis increased H2O2 concentrations inside leaf cells,enhanced the expression of FD(floral regulatory gene)and API(floral meristem identity gene)at the shoot apex,and induced early flowering.Our further study found that early flowering no longer occurred by RfBP gene silencing,flowering was delayed by the external riboflavin application,which brought gene expression and flavins back to the steady-state levels but only caused 55%reduction of H2O2 concentrations in RfBP+ plants.Exogenous H2O2 treatment could reasult in early flowering and inhance the expression of FD and AP1.We aslo observed that H2O2 from different sources contribute to the similar effects on flowering. |
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