Isolation and characterisation of latex cyanogenic glucosidase in Hevea brasiliensis

Sunderasan E., Chow Keng See, Ward M.A., Yeang Hoong Yeet. 2001. Isolation and characterisation of latex cyanogenic glucosidase in Hevea brasiliensis. In : Biotechnology and rubber tree : Proceedings of IRRDB symposium, 25-28 September 2001, Montpellier, France. Sainte-Beuve Jérôme (ed.). IRRDB, CIRAD-CP-HEVEA. Montpellier : CIRAD IRRDB Symposium, Montpellier, France, 25 Septembre 2001/28 Septembre 2001.

Résumé : Latex from the rubber tree (Hevea brasiliensis) is separated into the rubber cream, the clear aqueous phase (C-serum), and the sediment, which consists mainly of vacuole-like organelles called lutoids by high-speed centrifugation. The fluid content of the latter, known as B-serum has drawn attention for many years, owing to its hydrolytic enzymes and pathogenesis-related proteins. A number of these proteins were also pursued in latex allergy studies. [bêta]-glucosidase is among the first hydrolases detected in the H. brasiliensis latex B-serum. It is in the leaf tissue, however, that a [bêta]-glucosidase was first isolated and purified. Besides [bêta]-monoglucosides, this enzyme from Hevea leaves cleaves a wide range of indigenous heteroglycosides including coniferin and cyanoglucosides (linamarin and lataustralin) indicating a possible role in lignification and cyanogenesis. Accordingly it is given the name cyanogenic glycosidase (linamarase). In cassava, hydrolysis of cyanoglucosides by linamarase produces cyanohydrins and glucose. Subsequent breakdown of cyanohydrins either spontaneous or by an á-hydroxynitrile lyase releases a ketone and hydrogen cyanide (HCN), which among others has a role in plant defense. Likewise, the H. brasiliensis linamarase has been implicated in the resistance against South American Leaf Blight, a devastating disease caused by the pathogenic fungi Microcyclus ulei. The present study is aimed at isolating, identifying and characterising a cyanogenic [bêta]-glucosidase in the B-serum, as well as cloning and sequencing of its transcript in H. brasiliensis latex.

Classification Agris : F60 - Physiologie et biochimie végétale

Auteurs et affiliations

• Sunderasan E., MRB (MYS)
• Chow Keng See, MRB (MYS)
• Ward M.A.
• Yeang Hoong Yeet, MRB (MYS)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/513739/)

Métriques

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