Effect of Cycocel derivatives and gibberellin on choline kinase and choline metabolism

Genome-wide identification of CK gene family suggests functional expression pattern against Cd2+ stress in Gossypium hirsutum L

Choline kinase (CK) gene plays an important role in plants growth, development and resistance to stress. It mainly regulates the biosynthesis of phosphatidylcholine. This study aims to explore the structure-function relationship, and to provide a framework for functional validation and biochemical characterization of various CK genes. Our analysis showed that 87 CK genes were identified in cotton and 7 diploid plants, of which 43 genes encode CK proteins in 4 cotton species, and 13 genes were identified in Gossypium hirsutum. Most of GhCK genes are affected by the abiotic stress conditions, indicating the importance of CK proteins for plant development and response to abiotic stress. RT-qPCR analysis showed the tissue specificity of GhCK genes in response to Cd²⁺ and other abiotic stresses. Under Cd²⁺ stress, the expression level of GhCK gene family members has undergone different changes. The expression level of GhCK5 was enhanced, indicating that Cd²⁺ stress caused the increase of phosphatidylcholine content, which in turn reacted on the plant cell membrane, finally reached the absorption of Cd²⁺ into plant cells to repair Cd²⁺ the purpose of contaminated soil. This study will further broaden our understanding of the association between evolution and function of the GhCK gene family.

Hormonal regulation of phosphatidylcholine synthesis in plants. The inhibition of cytidylyltransferase activity by indol-3-ylacetic acid

Indol-3-ylacetic acid stimulated stem elongation within 1 h of treatment of Pisum sativum L. cv. Feltham First stem sections. This elongation was accompanied by an increase in the endogenous level of phosphocholine and a decrease in that of CDP-choline. Measurements in vitro of the CDP-base pathway enzymes showed an increase in choline phosphotransferase and a decrease in cytidylyltransferase activity on hormone treatment. These results indicate that the decrease in phosphatidylcholine labelling from [14C]choline that is observed on indol-3-ylacetic acid treatment of pea stem sections is caused by the decrease in cytidylyltransferase activity.

Inhibition of phosphatidylcholine synthesis in mammary tissue by 2-chloroethyltrimethylammonium chloride

The incorporation of choline into phosphatidylcholine in mammary tissue from lactating cows is impeded by 2-chloroethyltrimethylammonium chloride at concentrations ranging from 0.3 to 9mm. This compound is a non-competitive inhibitor of choline kinase (K(m) 0.25mm), having K(i) 17mm. It is suggested that 2-chloroethyltrimethylammonium chloride may inhibit choline entry into the tissue.