β-ODAP accumulation could be related to low levels of superoxide anion and hydrogen peroxide in Lathyrus sativus L.

Level of the neuroexcitatory β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) in grass pea (Lathyrus sativus L.) varies with development and environmental stress. Reactive oxygen species (ROS) (mainly O2− and H2O2) are frequently reported to play important roles in plant development and in response to various stresses. To investigate the possible inter-relationship between contents of β-ODAP and ROS, grass pea leaves have been analyzed for contents of β-ODAP, O2− and H2O2. The results showed that leaves containing high levels of β-ODAP, exhibited low levels of O2− and H2O2, while leaves with high contents of O2− and H2O2 accumulated little β-ODAP. The application of pyridine or ABA which inhibit the production of O2− or H2O2 led to an increase in β-ODAP contents in intact or detached young leaves, whereas inhibition of catalase activity using AT (3-amino-1,2,4-triazole), leading to an increase in H2O2 content, result in significant decrease in β-ODAP levels of detached young leaves. In addition, inoculation of Rhizobium to young seedlings enhanced O2− and H2O2 levels, but reduced β-ODAP contents in shoots. These results suggest that β-ODAP accumulation could be related to low levels of superoxide anion and hydrogen peroxide in grass pea tissues.