Open AccessThe Myrosinase‐Binding Protein from Brassica Napus Seeds Possesses lectin Activity and has a Highly Similar Vegetatively Expressed Wound‐Inducible Counterpart
Author(s) -
Taipalensuu Jan,
Eriksson Susanna,
Rask Lars
Publication year - 1997
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1997.00680.x
Subject(s) - methyl jasmonate , jasmonic acid , salicylic acid , abscisic acid , biochemistry , biology , lectin , complementary dna , brassica , myrosinase , agarose , botany , gene , glucosinolate
This communication demonstrates that proteins in the family of myrosinase‐binding proteins (MBP) present in seeds of Brassica napus possess lectin activity, binding most efficiently to p‐aminophenyl α L‐D‐mannopyranoside–agarose, and to some extent to N‐acetylglucosamine–agarose. A cDNA encoding a vegetatively expressed, wound‐inducible counterpart to these seed MBP was isolated and characterised. Upon wounding, this MBP transcript accumulated in old and young leaves, and was systemically expressed in the young plant. Additionally, the wound‐induced MBP transcript increased in abundance after treating the young plants with methyl jasmonate (MeJA), jasmonic acid (JA) or abscisic acid (ABA), and to some extent in response to the ethylene precursor 1‐aminocyclopropane‐1‐carboxylic acid. Expression induced by wounding, ABA or JA was antagonised by simultaneous feeding of the plants with salicylic acid. MBP polypeptides accumulated in MeJA‐treated plants. The myrosinases redistributed from the soluble fraction into the insoluble fraction of a tissue extract after induction. The most abundant MBP (94 kDa) partitioned in the insoluble fraction, while two larger MBP (103 kDa and 108 kDa) were present only in the soluble fraction of extracts obtained from the control or MeJA‐treated plant tissues.