Characterization of protein kinase PsSRPKL, a novel pathogenicity factor in the wheat stripe rust fungus

Abstract

As in other eukaryotes, protein kinases (PKs) are generally evolutionarily conserved and play major regulatory roles in plant pathogenic fungi. Many PKs have been proven to be important for pathogenesis in model fungal plant pathogens, but little is currently known about their roles in the pathogenesis of cereal rust fungi, devastating pathogens in agriculture worldwide. Here, we report on an in planta highly induced PK gene PsSRPKL from the wheat stripe rust fungus Puccinia striiformis f. sp. tritici (Pst), one of the most important cereal rust fungi. PsSRPKL belongs to a group of PKs that are evolutionarily specific to cereal rust fungi. It shows a high level of intraspecies polymorphism in the kinase domains and directed green fluorescent protein chimers to plant nuclei. Overexpression of PsSRPKL in fission yeast induces aberrant cell morphology and a decreased resistance to environmental stresses. Most importantly, PsSRPKL is proven to be an important pathogenicity factor responsible for fungal growth and responses to environmental stresses, therefore contributing significantly to Pst virulence in wheat. We hypothesize that cereal rust fungi have developed specific PKs as pathogenicity factors for adaptation to their host species during evolution. Thus, our findings provide significant insights into pathogenicity and virulence evolution in cereal rust fungi.

Haustoria – arsenals during the interaction between wheat and Puccinia striiformis f. sp. tritici

“…For example, Pst_12394 was significantly up‐regulated at 18 h post‐inoculation (hpi), with a peak at 48 hpi. In general, 18–48 hpi is considered an important stage for infectious hypha and haustorium formation, and this early stage of infection is critical for pathogen colonization (Cheng et al , ). Expressions of Pst_16188 and Pst_19493 were up‐regulated from urediospore germination, peaking at 256 hpi (Fig.…”

PSTha5a23, a candidate effector from the obligate biotrophic pathogen Puccinia striiformis f. sp. tritici, is involved in plant defense suppression and rust pathogenicity

“…Recently, host-induced gene silencing (HIGS) has been developed and has proven to be a useful tool to study genes in obligate biotrophic pathogens (Nowara et al, 2010;Yin and Hulbert, 2015). Several Pst genes were shown to be important for rust pathogenicity or fungal growth using the barley stripe mosaic virus (BSMV)-mediated HIGS system Zhang et al, 2012;Cheng et al, 2015;Tang et al, 2015;Cheng et al, 2016).…”

The transcription factor PstSTE12 is required for virulence of Puccinia striiformis f. sp. tritici

“…Sexual reproduction is the primary process contributing to the origin of new races with combined virulence genes and diversification of stripe rust pathogens (Zhao et al ., ). Although some virulence‐related genes have been described in Pst (Cheng et al ., ; Liu et al ., ; Tang et al ., ), fewer studies have documented the genes that are involved in mating in Pst . A previous study has reported that the orthologue STE12 , together with other components, contributes to the regulation of fertility in sexual crosses in heterothallic fungi, such as S .…”