2 and TaHsp90.3 were positive contributors in the wheat hypersensitive reaction to stripe rust fungus [50] and [51]. These studies suggested that VIGS is an effective reverse genetic tool for investigating the functions of genes in wheat by knocking down the transcripts of target genes during the development

of disease resistance. Conventional methods for gene BIBF-1120 functional analysis of plant genes, including transformation are not easily accomplished given wheat’s large genome [52]. Transformation is also time-consuming because the function of a target gene should be tested over multiple generations [53]. In contrast to the conventional methods, the main advantage of VIGS is the generation of a rapid phenotype without the need for plant transformation [54]. Moreover, the VIGS method provides a large-scale screening of genes for functional analysis; only a single plant is enough to follow phenotype with targeted silencing [55]. In this study, the VIGS approach was utilized to investigate the function of TaWAK5 in wheat defense response to R. cerealis. Although the TaWAK5 transcript level was reduced in CI12633 plants infected by BSMV:TaWAK5, down-regulation of TaWAK5 in resistant CI12633 did not result in an obvious impairment of wheat resistance to R. cerealis. Plant defense is a complicated network in which some components Z-VAD-FMK clinical trial and network sectors interact with each other

in complex ways. The function of an individual component of a network can be compensated for by some other component. Therefore, functional characterization of disease resistance components by knockout of an individual component is difficult and multi-gene

knock outs or gene × gene interactions need to be considered [56]. In Arabidopsis, it has been suggested that there is functional redundancy Rucaparib mw between the WAKs, as induced silencing of individual AtWAK1or AtWAK2 using gene-specific antisense transcripts did not cause any phenotypic alteration [57]. In this study, knocking down TaWAK5 expression did not cause the compromised resistance phenotype of the host CI12633 to R. cerealis. The reason might be that TaWAK5 is not the major gene controlling wheat defense response to R. cerealis, or that TaWAK5 is functionally redundant with other wheat WAK genes that help replace its functionalities when it is knocked out by VIGS experiments. A wheat WAK gene, TaWAK5, was identified by microarray analysis of differentially expressed genes between R. cerealis-resistant line CI12633 and susceptible cv. Wenmai 6 and characterized. TaWAK5 was rapidly induced by R. cerealis infection, and by exogenous SA, MeJA, or ABA application. The deduced TaWAK5 protein shares the structural characteristic of a wall-associated kinase, possessing two EGF-like repeats and a kinase catalytic domain. The TaWAK5 protein was localized to the plasma membranes in onion epidermal cells.