Metabolic routes of β-(isoxazolin-5-on-2-yl)-L-alanine (BIA), the precursor of the neurotoxin ODAP (β-N-oxalyl-L-α,β,-diaminopropionic acid), in different legume seedlings

BIA, beta-(isoxazolin-5-on-2-yl)-alanine, is formed in high concentrations in the seedling stage of many plants belonging to the tribe Vicieae. The metabolism of this compound in different legume seedlings has been studied by radioisotope feeding. In Lathyrus sativus, BIA is metabolised to the neurotoxin ODAP (beta-N-oxalyl-alpha,beta-diaminopropionic acid) and the gamma-glutamyl derivative of BIA. In L. odoratus seedlings BIA is metabolised to the decarboxylation product of the glutamyl derivative, and the glutamyl derivative is proposed as an intermediate. In Pisum sativum seedlings, the main part of BIA is not further metabolised. While in Lens culinaris seedlings, besides the formation of the glutamyl derivative, another four unknown amino acids were found. Approaches for the detoxification of Lathyrus sativus by genetic transformation are suggested. (C) 1998 Elsevier Science Ltd. All rights reserved.