DEVELOPMENTAL REGULATION OF LECTIN AND ALLIINASE SYNTHESIS IN GARLIC BULBS AND LEAVES

Using a combination of northern blot analysis and sodium dodecyl sulfa te-polyacrylamide gel electrophoresis, a detailed study was made of th e temporal and spatial regulation of garlic (Allium sativum L.) lectin s and alliinase throughout the life cycle of the plant. The two bulb-s pecific lectins (ASAI and ASAII), which are the most predominant bulb proteins, accumulate exclusively in the developing garlic cloves and p rogressively disappear when the old clove is consumed by the young pla nt. On the basis of these observations, ASAI and ASAII can be regarded as typical vegetative storage proteins. The leaf-specific lectin (ASA L), on the contrary, is specifically synthesized in young leaves and r emains present until withering. Because ASAL is only a minor protein, it probably fulfills a specific function in the plant. Unlike the lect ins, alliinase is present in large quantities in bulbs as well as in l eaves. 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 de fense against pathogens and/or predators.