PLANT PHYSIOLOGY , Vol 113, Issue 3 765-771, Copyright © 1997 by American Society of Plant Biologists
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DEVELOPMENT AND GROWTH REGULATION |
Developmental Regulation of Lectin and Alliinase Synthesis in Garlic Bulbs and Leaves
K. Smeets, EJM. Van Damme and W. J. Peumans
Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Willem de Croylaan 42, 3001 Heverlee-Leuven, Belgium
Using a combination of northern blot analysis and sodium dodecyl
sulfate-polyacrylamide gel electrophoresis, a detailed study was made of
the temporal and spatial regulation of garlic (Allium sativum L.) lectins
and alliinase throughout the life cycle of the plant. The two bulb-specific
lectins (ASAI and ASAII), which are the most predominant bulb proteins,
accumulate exclusively in the developing garlic cloves and progressively
disappear when the old clove is consumed by the plant. On the basis of
these observations, ASAI and ASAII can be regarded as typical vegetative
storage proteins. The leaf-specific lectin (ASAL), on the contrary, is
specifically synthesized in young leaves and remains present until
withering. Because ASAL is only a minor protein, it probably fulfills a
specific function in the plant. Unlike the lectins, alliinase is present in
large quantities in bulbs as well as in leaves. Moreover, intact alliinase
mRNAs are present in both tissues as long as they contain living cells. The
latter observation is in good agreement with the possible involvement of
alliinase in the plant's defense against pathogens and/or predators.
