TaTHI2 interacts with Ca²⁺‐dependent protein kinase TaCPK5 to suppress virus infection by regulating ROS accumulation

Abstract

SummaryThiamine (vitamin B1) biosynthesis involves key enzymes known as thiazole moieties (THI1/THI2), which have been shown to participate in plant responses to abiotic stress. However, the role of THI1/THI2 in plant immunity remains unclear. In this study, we cloned TaTHI2 from wheat and investigated its function in Chinese wheat mosaic virus (CWMV) infection. Overexpression of TaTHI2 (TaTHI2‐OE) inhibited CWMV infection, while TaTHI2 silencing enhanced viral infection in wheat. Interestingly, the membrane‐localized TaTHI2 protein was increased during CWMV infection. TaTHI2 also interacted with the Ca2+‐dependent protein kinase 5 (TaCPK5), which is localized in the plasma membrane, and promoted reactive oxygen species (ROS) production by repressing TaCPK5‐mediated activity of the catalase protein TaCAT1. CWMV CP disrupted the interaction between TaTHI2 and TaCAT1, reducing ROS accumulation and facilitating viral infection. Additionally, transgenic plants overexpressing TaTHI2 showed increased seed number per ear and 1000‐kernel weight compared to control plants. Our findings reveal a novel function of TaTHI2 in plant immunity and suggest its potential as a valuable gene for balancing disease resistance and wheat yield. Furthermore, the disruption of the TaTHI2‐mediated plant immune pathway by CWMV CP provides further evidence for the evolutionary arms race between plants and viruses.

Abnormal Calcium Accumulation and ROS Homeostasis-Induced Tapetal Programmed Cell Death Lead to Pollen Abortion of Petaloid-Type Cytoplasmic Male Sterility in Camellia oleifera

“…Cellular calcium homeostasis depends on Ca 2+ -ATPase and the expression of related genes. It has been reported that Ca 2+ -dependent kinase 5 can promote ROS production by inhibiting the activity of CPK5-mediated catalase protein CAT1 [24]. Our results show that CoCPK was highly expressed in early pollen development.…”

“…These proteins include calcium-dependent protein kinases (CDPK/CPKs) and CPK-associated protein kinases (CRKs), and calcium-and calmodulin-dependent protein kinases (CCaMKs) and calmodulins (CaMs) [23]. Ca 2+ -dependent protein kinase 5 (TaCPK5), located on the plasma membrane in wheat, can promote ROS production by inhibiting the activity of TACPK5-mediated catalase protein TaCAT1 [24].…”

Genome-Wide Analysis and Identification of UDP Glycosyltransferases Responsive to Chinese Wheat Mosaic Virus Resistance in Nicotiana benthamiana

“…Briefly, the inoculation leaves of N. benthamiana were sampled with a puncher; then, the samples were placed on a glass slide and covered with a coverslip before being observed under the microscope. LAS X is equipped with channels to observe different fluorescence, such as GFP, RFP, and YFP, and it also has a special chloroplast channel that can be used to observe whether the gene can express in the chloroplasts [ 41 ]. When detecting the fluorescence signal, the excitation and emission wavelengths of the GFP fluorescence were 488 nm and 500–555 nm, respectively, the RFP fluorescence excitation and emission wavelengths were 552 nm and 565–620 nm, respectively, while those of the chloroplast fluorescence excitation and emission wavelengths were 552 nm and 670–730 nm, respectively.…”

“…The chloroplasts were extracted using the MinuteTM Chloroplast Isolation Kit (Invent Biotechnologies, Beijing, China) according to the manufacturer’s instructions. Subsequently, the resulting samples were analyzed using WB analysis [ 41 ].…”