Hyperhydricity in pepper plants regenerated in vitro: involvement of BiP (Binding Protein) and ultrastructural aspects

• Published in: Plant cell reports 1999-11, Vol.19 (1), p.81-87
• Main Authors: Fontes, M A, Otoni, W C, Carolino, S M B, Brommonschenkel, S H, Fontes, E P B, Fári, M, Louro, R P
• Format: Article
• Language: English
• Subjects: Accumulation; BiP protein; Capsicum annuum; Chloroplasts; Leaves; Soybeans; Starch
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s002990050714

Hyperhydricity in regenerated pepper plants was monitored by the induction of the ER-luminal resident protein, as observed by immunoblotting. Immunoblotting of total protein using an anti-soybean BiP serum indicated that the induction and accumulation of an 80-kDa protein was related to BiP (Binding protein), a 78-kDa ER-resident molecular chaperone. The anti-BiP serum cross-reacted with an 80-kDa protein which was significantly induced by hyperhydricity. Based on similar molecular weight and immunological reactivity we concluded that the 80-kDa protein induced in hyperhydric plants is a BiP homologue. The ultrastructural organisation of leaves in non-hyperhydric and hyperhydric pepper (Capsicum annuum L.) plants was investigated with the aim of identifying the subcellular changes associated with this phenomenon. In non-hyperhydric leaves the chloroplasts of the palisade cells had normally developed thylakoids and grana and a low accumulation or absence of starch grains and plastoglobules. In the hyperhydric plants, however, the chloroplasts exhibited thylakoid disorganisation, low grana number, an accumulation of large starch grains and a low accumulation or absence of plastoglobules. Although the structure of mitochondria and peroxisomes did not change in hyperhydric plants, the number of peroxisomes did increase.