title: Abscisic acid promotes accumulation of toxin ODAP in relation to free spermine level in grass pea seedlings (Lathyrus sativus L.).
abstract: Interrelationship among abscisic acid (ABA) content, accumulation of free polyamines and biosynthesis of beta-N-oxalyl-l-alpha,beta-diaminopropionic acid (ODAP) was studied in grass pea (Lathyrus sativus L.) seedlings under drought stress induced by 10% polyethylene glycol (PEG6000). Increase of ABA content occurred prior to that of ODAP and polyamine contents, and was found significantly positive correlation between ABA content and ODAP content. Addition of exogenous ABA increased ODAP content in leaves. On the other hand, pretreatment with alpha-difluoromethylarginine (DFMA), a polyamine biosynthesis inhibitor, significantly suppressed the accumulation of free putrescine (Put), free spermidine (Spd) and free spermine (Spm), which in turn inhibited biosynthesis of ODAP in well-watered leaves. Meanwhile, addition of exogenous Put alleviated DFMA-induced inhibition on the biosynthesis of Put and Spd, but did not affect the biosynthesis of Spm and ODAP in well-watered leaves. Same result was also achieved in drought-stressed leaves. Increasing accumulation of ODAP was significantly correlated with increasing Spm content (R=0.7957**) but not with that of Spd and Put. Therefore, it can be argued that ABA stimulated the biosynthesis of ODAP simultaneously with increasing the level of free Spm under drought stress condition.
authors.affiliation: MOE Key Laboratory of Arid and Grassland Ecology, Lanzhou University, Tianshui Road, 730000 Lanzhou, Gansu, China.
authors.forename: You-Cai
authors.initials: YC
authors.lastname: Xiong
authors.forename: Geng-Mei
authors.initials: GM
authors.lastname: Xing
authors.forename: Feng-Min
authors.initials: FM
authors.lastname: Li
authors.forename: Shao-Ming
authors.initials: SM
authors.lastname: Wang
authors.forename: Xian-Wei
authors.initials: XW
authors.lastname: Fan
authors.forename: Zhi-Xiao
authors.initials: ZX
authors.lastname: Li
authors.forename: Ya-Fu
authors.initials: YF
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000599:Amino Acids, Diamino / Q000378:metabolism*; D027807:Lathyrus / Q000187:drug effects* / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000494:pharmacology; D036226:Seedlings; D013096:Spermine / Q000378:metabolism*; D013997:Time Factors; D014867:Water / Q000378:metabolism
chemical_list: D000599:Amino Acids, Diamino; D010937:Plant Growth Regulators; D014867:Water; C100126:oxalyldiaminopropionic acid; D013096:Spermine; D011092:Polyethylene Glycols; D000040:Abscisic Acid