Post harvest diseases fruits and vegetables - Xavier University ...

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
188 Postharvest Diseases of Fruits and Vegetables
all the major groups of lectin specificity. A growth disruption during
germination of spores was reported for three fungal species, including the
postharvest pathogen Botryodiplodia theobromae (Brambl and Gade,
1985). According to a subsequent report, however, the antifungal activity
of WGA was most likely due to contaminating chitinases in the lectin
preparations used, which are known as potent inhibitors of fungal
growth (Schlumbaum et al., 1986). However, this criticism does not
invalidate the results obtained with lectins such as peanut and soybean
agglutinins, which are specific for sugars other than oligomers of
N-acetylglucosamine (Sharon and Lis, 1989). Furthermore, a
chitinase-free lectin obtained from stinging nettle (Urtica diocia), also
specific for chitin, was demonstrated to inhibit the growth of several
phytopathogenic fungi (Broekaert et al., 1989). The nettle lectin probably
acts by interfering with chitin synthesis by the fungi.
It should be mentioned, however, that although plant lectins have
shown antifungal activity towards various plant pathogenic fungi, no
protective role of these lectins has been demonstrated in vivo.
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