The induction of polyamines metabolism pathway and membrane stability with silicon alleviate the vanadium toxicity in pepper plants

Abstract

The vanadium (V) toxicity predominantly is the primary limitation restraining pepper growth. The silicon (Si) in pepper plants induced the transcript level of the polyamines metabolism pathway genes, including the arginase (CbARG), ornithine decarboxylase (CbODC), arginine decarboxylase (CbADC), N-carbamoylputrescine amidase (CbNCA), Spermidine synthase (CbSPDS), copper binding diamine oxidase (CbCuAO) to overcome the V toxicity. The polyamines, including the Spm, Spd, and Put, induced with Si about 41.37%, 33.12%, and 27.90%, respectively, in V stress. Moreover, the Si application decline in the leaf and root V contents, which was around 49.5% and 40.74%, respectively, then the V stress plants. The soluble protein, proline, and Si level in root/leaf with Si treatment significantly induced around 55.55/50.22%, 42.85/55.35%, and 49.92/85.29%, respectively, as compared to the V stress. Si also heightened the nitrate reductase (NR), phosphoenolpyruvate carboxylase (PEPC), and malate dehydrogenase (MDH) levels. Our study revealed that Si maintained the PSII integrity and induced PSII efficiency genes. Si preserves the membrane stability, as evidenced by less accumulation in EL, H₂O_2, and MDA levels. The Si also induces the AsA-GSH to eliminate the reactive oxygen species (ROS) in the pepper plants. In summary, our research elucidated that Si addition improved pepper plants' tolerance to V toxicity.