Ma. Fontes et al., Hyperhydricity in pepper plants regenerated in vitro: involvement of BiP (Binding Protein) and ultrastructural aspects, PL CELL REP, 19(1), 1999, pp. 81-87
Hyperhydricity in regenerated pepper plants was monitored by the induction
of the ER-luminal resident protein, as observed by immunoblotting. Immunobl
otting 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 cro
ss-reacted with an 80-kDa protein which was significantly induced by hyperh
ydricity. Based on similar molecular weight and immunological reactivity we
concluded that the 80-kDa protein induced in hyperhydric plants is a BiP h
omologue. The ultrastructural organisation of leaves in non-hyperhydric and
hyperhydric pepper (Capsicum annuum L.) plants was investigated with the a
im of identifying the subcellular changes associated with this phenomenon.
In non-hyperhydric leaves the chloroplasts of the palisade cells had normal
ly developed thylakoids and grana and a low accumulation or absence of star
ch grains and plastoglobules. In the hyperhydric plants, however, the chlor
oplasts exhibited thylakoid disorganisation, low grana number, an accumulat
ion of large starch grains and a low accumulation or absence of plastoglobu
les. Although the structure of mitochondria and peroxisomes did not change
in hyperhydric plants, the number of peroxisomes did increase.