The Calcium-Dependent Protein Kinase TaCDPK7 Positively Regulates Wheat Resistance to Puccinia striiformis f. sp. tritici .

Ca 2+ plays a crucial role as a secondary messenger in plant development and response to abiotic/biotic stressors. Calcium-dependent protein kinases (CDPKs/CPKs) are essential Ca 2+ sensors that can convert Ca 2+ signals into downstream phosphorylation signals. However, there is limited research on the function of CDPKs in the context of wheat- Puccinia striiformis f. sp. tritici ( Pst ) interaction. In this study, we aimed to address this gap by identifying putative CDPK genes from the wheat reference genome and organizing them into four phylogenetic clusters (I-IV). To investigate the expression patterns of the TaCDPK family during the wheat- Pst interaction, we analyzed time series RNA-seq data and further validated the results through qRT-PCR assays. Among the TaCDPK genes, TaCDPK7 exhibited a significant induction during the wheat- Pst interaction, suggesting that it has a potential role in wheat resistance to Pst . To gain further insights into the function of TaCDPK7 , we employed virus-induced gene silencing (VIGS) to knock down its expression which resulted in impaired wheat resistance to Pst , accompanied by decreased accumulation of hydrogen peroxide (H 2 O 2 ), increased fungal biomass ratio, reduced expression of defense-related genes, and enhanced pathogen hyphal growth. These findings collectively suggest that TaCDPK7 plays an important role in wheat resistance to Pst . In summary, this study expands our understanding of wheat CDPKs and provides novel insights into their involvement in the wheat- Pst interaction.