The wheat calcium‐dependent protein kinase TaCPK7‐D positively regulates host resistance to sharp eyespot disease

Abstract

Sharp eyespot, caused mainly by the necrotrophic fungus Rhizoctonia cerealis, limits wheat production worldwide. Here, TaCPK7-D, encoding a subgroup III member of the calcium-dependent protein kinase (CPK) family, was identified from the sharp eyespot-resistant wheat line CI12633 through comparative transcriptomic analysis. Subsequently, the defence role of TaCPK7-D against R. cerealis infection was studied by the generation and characterization of TaCPK7-D-silenced and TaCPK7-D-overexpressing wheat plants. Rhizoctonia cerealis inoculation induced a higher transcriptional level of TaCPK7-D in the resistant wheat line CI12633 than in the susceptible cultivar Wenmai 6. The expression of TaCPK7-D was significantly induced after exogenous application of 1-aminocyclopropane-1-carboxylic acid (an ethylene biosynthesis precursor). The green fluorescent protein signal distribution assays indicated that TaCPK7-D localizes to the plasma membrane in both onion epidermal cells and wheat protoplasts. Following R. cerealis inoculation, TaCPK7-D-silenced wheat CI12633 plants displayed more severe sharp eyespot symptoms than control CI12633 plants. Four defence-associated genes (β-1,3-glucanase, chitinase 1, defensin and TaPIE1) and an ethylene biosynthesis key gene, ACO2, were significantly suppressed in the TaCPK7-D-silenced wheat plants compared with control plants. Conversely, TaCPK7-D-overexpressing wheat lines showed increased resistance to sharp eyespot compared with untransformed recipient wheat Yangmai 16. Furthermore, the transcriptional levels of these four defence-related genes and ACO2 gene were significantly elevated in TaCPK7-D-overexpressing plants compared with untransformed recipient wheat plants. These results suggest that TaCPK7-D positively regulates the wheat resistance response to R. cerealis infection through the modulation of the expression of these defence-associated genes, and that TaCPK7-D is a candidate to improve sharp eyespot resistance in wheat.

GhCPK33 Negatively Regulates Defense against Verticillium dahliae by Phosphorylating GhOPR3

“…Phosphorylation of BIK1 by AtCPK28 leads to its degradation by the 26S proteasome and results in the attenuation of PTI signaling (Monaghan et al, 2014(Monaghan et al, , 2015Wang et al, 2018a). Additionally, several reports in rice (Oryza sativa), maize (Zea mays), wheat (Triticum aestivum), potato (Solanum tuberosum), and pepper (Capsicum annuum) confirm that CPK proteins participate in the plant defense response via regulating reactive oxygen species accumulation, biosynthesis of defense-associated phytohormones, and other aspects of the plant immune system by phosphorylating specific substrate proteins (Geng et al, 2013;Shen et al, 2016;Wei et al, 2016;Bundó and Coca, 2017;Fantino et al, 2017;Wang et al, 2018b). In our study, we demonstrate that the cotton calcium-dependent protein kinase CPK33 phosphorylates the key JA biosynthesis-related protein OPR3 to regulate plant immunity through modulating stress-induced JA accumulation (Fig.…”

A novel cysteine‐rich receptor‐like kinase gene, TaCRK2, contributes to leaf rust resistance in wheat

“…Plants overexpressing CBL‐interacting protein kinase 6 negatively regulate immunity and were more susceptible to Pseudomonas syringae in Arabidopsis (Sardar et al , 2017). Wheat calcium‐dependent protein kinase TaCPK7‐D overexpression activates defence‐related genes, leading to enhanced resistance to sharp eyespot caused by Rhizoctonia cerealis , and positively regulates host resistance to sharp eyespot disease (Wei et al , 2016).…”

The wheat R2R3-MYB transcription factor TaRIM1 participates in resistance response against the pathogen Rhizoctonia cerealis infection through regulating defense genes

“…At least 10 plants for each wheat line were inoculated with developed mycelia of R. cerealis following the protocol of Wei et al . 44 . In T 1 generation, R. cerealis WK207 was used to inoculate plants, whereas R. cerealis isolate R0301 was used to inoculate T 2 and WT plants.…”