D6 protein kinase in root xylem benefiting resistance to Fusarium reveals in fection and defense mechanisms in tung trees

Fusarium oxysporum,a global soil-borne pathogen,causes severe disease in various cultivated plants.The mechanism underlying infection and resistance remains largely elusive.Vernicia fordii,known as the tung tree,suffers from disease caused by F.oxysporum f.sp.fordiis(Fof-1),while its sister species V.montana displays high resistance to Fof-1.To investigate the process of infection and resistance ability,we demonstrated that Fof-1 can penetrate the epidermis of root hairs and then centripetally invade the cortex and phloem in both species.Furthermore,Fof-1 spread upwards through the root xylem in susceptible V.fordii trees,whereas it failed to infect the root xylem in resistant V.montana trees.We found that D6 PROTEIN KINASE LIKE 2(VmD6PKL2)was speci fically expressed in the lateral root xylem and was induced after Fof-1 infection in resistant trees.Transgenic analysis in Arabidopsis and tomato revealed that VmD6PKL2 signi ficantly enhanced resistance in both species,whereas the d6pkl2 mutant displayed reduced resistance against Fof-1.Additionally,VmD6PKL2 was identi fied to interact directly with synaptotagmin(VmSYT3),which is speci fically expressed in the root xylem and mediates the negative regulation responding to Fof-1.Our data suggested that VmD6PKL2 could act as a resistance gene against Fof-1 through suppression of VmSYT3-mediated negative regulation in the lateral root xylem of the resistant species.These findings provide novel insight into Fusarium wilt resistance in plants.

Optimal LQG control for discrete time-varying system with multiplicative noise and multiple state delays

This paper is concerned with the optimal linear quadratic Gaussian(LQG)control problem for discrete time-varying system with multiplicative noise and multiple state delays.The main contributions are twofolds.First,in virtue of Pontryagin’s maximum principle,we solve the forward and backward stochastic difference equations(FBSDEs)and show the relationship between the state and the costate.Second,based on the solution to the FBSDEs and the coupled difference Riccati equations,the necessary and sufficient condition for the optimal problem is obtained.Meanwhile,an explicit analytical expression is given for the optimal LQG controller.Numerical examples are shown to illustrate the effectiveness of the proposed algorithm.