A multicystatin is induced by drought-stress in cowpea (Vigna unguiculata (L.) Walp.) leaves.
Cystatins are protein inhibitors of cystein proteinases belonging to the papain family. In cowpea, cystatin-like polypeptides and a cDNA have been identified from seeds and metabolic functions have been attributed to them. This paper describes VuC1, a new cystatin cDNA isolated from cowpea leaves (Vigna unguiculata (L.) Walp.). Sequence analysis revealed a multicystatin structure with two cystatin-like domains. The recombinant VUC1 protein (rVUC1) was expressed in an heterologous expression system and purified to apparent homogeneity. It appeared to be an efficient inhibitor of papain activity on a chromogenic substrate. Polyclonal antibodies against rVUC1 were obtained. Involvement of the VuC1 cDNA in the cellular response to various abiotic stresses (progressive drought-stress, dessication and application of exogenous abscissic acid) was studied, using Northern blot and Western blot analysis, in the leaf tissues of cowpea plants corresponding to two cultivars with different capacity to tolerate drought-stress. Surprisingly, these abiotic stresses induced accumulation of two VuC1-like messages both translated into VUC1-like polypeptides. Difference in the transcript accumulation patterns was observed between the two cultivars and related to their respective tolerance level. Presence of multiple cystatin-like polypeptides and their possible involvement in the control of leaf protein degradation by cysteine proteinases is discussed.
Diop
Ndeye Ndack
NN
Laboratoire d'Ecophysiologie moléculaire, UMR/IRD 137, FST, Université Paris 12 - Val de Marne, 61 Avenue du Général de Gaulle, 94 010 Créteil cedex, France.
Kidric
Marjetka
M
Repellin
Anne
A
Gareil
Monique
M
d'Arcy-Lameta
Agnés
A
Pham Thi
Anh Thu
AT
Zuily-Fodil
Yasmine
Y
D000595:Amino Acid Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D015891:Cystatins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D004190:Disasters; D007887:Fabaceae / Q000737:chemistry / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010206:Papain / Q000037:antagonists & inhibitors; D018515:Plant Leaves / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014158:Transcription, Genetic
D015891:Cystatins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D010206:Papain