王剑文课题组在J Plant Growth Regul发表科研论文

Glaucocalyxin A and B Regulate Growth and Induce Oxidative Stress in Lettuce (Lactuca sativa L.) Roots
WH Yang, LP Zheng, HY Yuan, JW Wang*
J Plant Growth Regul (2014) 33:384–396 (IF2013=2.058)

Abstract: Glaucocalyxin (Gla) A-C are major ent-kaurane diterpenoids isolated from Isodon japonicus var. glaucocalyx (Maxim.) H.W.Li. This study investigated the possible interference of these diterpenoids with root growth and its mechanism of action in lettuce (Lactuca sativa L.) seedlings. Results indicated the dual stimulatory and inhibitory effects of Gla A, B on root growth and their phytotoxic effects on root hair development. The promotion of root growth by lower levels of Gla A, B (20-40 M) resulted from enhanced cell length and increased mitotic activity. But higher concentrations (80-200 M) of Gla A, B had inhibitory effects. In addition, Gla A and B inhibited root hair development of lettuce seedlings in a dose-dependent manner at concentrations between 20 and 200 μM. Exposure of lettuce roots to Gla A and B at 200 M increased levels of malondialdehyde and the generation of O2−, indicating lipid peroxidation and induction of oxidative stress. Activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were significantly elevated. Reactive oxygen species (ROS) scavengers dihydroxybenzene disulphonic acid (Tiron) and dimethylthiourea (DMTU) at 100 µM could efficiently alleviate the phytotoxicity induced by Gla A, B at 200 M. These results demonstrated that the deleterious effect of Gla A, B at higher concentration (80-200 M) on roots may occur through the imposition of an oxidative stress on the cell growth and cell division. Due to the lack of an , -unsaturated ketone in -methylenecyclopentanone moiety, Gla C could not induce ROS generation and exhibited no effect on the roots, even at the highest concentration (200 μM). Therefore, the-methylenecyclopentanone moiety in the ent-kaurene diterpenoids was presented as an essential possible active centre for the phytototoxicity.