TaWAK2A-800, a Wall-Associated Kinase, Participates Positively in Resistance to Fusarium Head Blight and Sharp Eyespot in Wheat

Abstract

Fusarium head blight (FHB) and sharp eyespot are important diseases of the cereal plants, including bread wheat (Triticum aestivum) and barley. Both diseases are predominately caused by the pathogenic fungi, Fusarium graminearum and Rhizoctonia cerealis. The roles of the wheat-wall-associated kinases (WAKs) in defense against both F. graminearum and R. cerealis have remained largely unknown. This research reports the identification of TaWAK2A-800, a wheat WAK-coding gene located on chromosome 2A, and its functional roles in wheat resistance responses to FHB and sharp eyespot. TaWAK2A-800 transcript abundance was elevated by the early infection of R. cerealis and F. graminearum, or treatment with exogenous chitin. The gene transcript seemed to correspond to the resistance of wheat. Further functional analyses showed that silencing TaWAK2A-800 compromised the resistance of wheat to both FHB (F. graminearum) and sharp eyespot (R. cerealis). Moreover, the silencing reduced the expression levels of six defense-related genes, including the chitin-triggering immune pathway-marker genes, TaCERK1, TaRLCK1B, and TaMPK3. Summarily, TaWAK2A-800 participates positively in the resistance responses to both F. graminearum and R. cerealis, possibly through a chitin-induced pathway in wheat. TaWAK2A-800 will be useful for breeding wheat varieties with resistance to both FHB and sharp eyespot.

Characterization of the WAK Gene Family Reveals Genes for FHB Resistance in Bread Wheat (Triticum aestivum L.)

“…For the genes that were not induced in this study, the possibility of their participation in FHB resistance cannot be eliminated. For example, TaWAK2A-800 reportedly participates positively in the resistance responses to FHB; however, it was significantly induced upon Fg inoculation in the FHB-resistant wheat cultivar, Sumai 3 [24] but not in this study. This difference may result from the expression analysis in different varieties or the conditions of Fg treatment.…”

“…According to previous research, pectin and chitin can trigger the expression of WAK genes. For example, TaWAK7D transcript levels were elevated after pectin and chitin treatments [20], TaWAK2A-800 was significantly induced by chitin treatment [24], and chitin triggered the expression of the rice OsWAK91/92/14 genes [14]. In this study, 19 of the 20 selected TaWAKs were elevated after exogenous pectin treatment, and 12 of the 20 TaWAKs were induced after exogenous chitin treatment, thus demonstrating that the TaWAK family may contribute to the pectinand chitin-induced defense pathway in wheat.…”

“…Although many quantitative trait loci (QTLs) associated with FHB resistance have been reported, only a few genes have been identified to confer FHB resistance [22]. For instance, WAK2 isolated from the QFhb.mgb-2A region of durum wheat, and the TaWAK2A-800 region of bread wheat is responsible for FHB resistance [23,24]. WAKs are now being recognized as playing important regulatory roles in plant immunity; therefore, the identification of new WAK genes that are critical for FHB responses facilitates the genetic manipulation of these candidates for improving FHB resistance in wheat breeding programs.…”

The Pathogen-Induced MATE Gene TaPIMA1 Is Required for Defense Responses to Rhizoctonia cerealis in Wheat

“…To date, no completely resistant wheat germplasm to R. cerealis has been identified, and chemical control is still limited [ 9 ]. Various studies have shown that using important resistance-associated genes would generate wheat with better resistance to sharp eyespot [ 5 , 6 , 9 , 10 , 11 , 12 , 13 , 14 ]. Therefore, exploration of effective resistance genes is a viable strategy to breeding wheat with resistance to sharp eyespot.…”

Wheat Breeding through Genetic and Physical Mapping 2

“…The next two papers studied the wheat-wall-associated kinase and like kinase receptors involved in pathogen resistance. Guo et al [10] wrote about the roles of the wheat-wallassociated kinases (WAKs) in defense against both F. graminearum and R. cerealis, which have remained largely unknown. This research reported the identification of TaWAK2A-800, a wheat WAK-coding gene located on chromosome 2A, and its functional roles in wheat resistance responses to FHB and sharp eyespot.…”