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Developmentaly specific soluble and membrane proteins and glycoproteins in Mammillaria Gracillis Pfeiff. (Cactaceae) tissue culture

Artificial environmental conditions in the tissue culture influence growth and induce spontaneous changes from characteristic organisation pattern to unorganised callus. As CAM plants, cacti are particularly susceptible to altered growth environment. In vitro propagated Mammillaria plants spontaneously produce callus which regenerates normal and hyperhydric shoots without the addition of growth regulators. In order to compare habituated callus with tumor, cactus cells were transformed with A. tumefaciens. Cactus tumour never expresses any organogenic potential. The aim of this work was to detect changes in protein and glycoprotein profiles in different developmental stages of Mammillaria tissues. Proteins were separated by SDS-PAGE and silver stained. Glycoproteins were detected according to their affinity to Con A, while the glycan component was further characterized with lectins GNA, DSA, MAA, PNA and SNA. Despite obvious morphological differences between Mammillaria tissues, only a few morphogenesis- specific polypeptides were observed. Differences were more pronounced in the glycoprotein pattern. According to the Con A- and GNA-profiles all cactus tissues were characterized by the presence of the 30, 40 and 44 kDa glycoproteins. Callus, hyperhydric regenerant and tumour had common band of 55 kDa, with stronger staining intensity in tumour. The 20 kDa band appeared in the shoot, while the glycoproteins of 46, 81 and 82 kDa were tumour-specific. No signal was observed with DSA, while PNA-, MAA- and SNA-profiles partially correlated with those detected with Con A and GNA. Obtained results demonstrate that the glycosylation of cellular proteins is changed if the characteristic organisation pattern of Mammillaria shoot is lost.

cacti ; callus ; lectins ; morphogenesis ; N-glycans ; tumor transformation

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