Plant Molecular Biology 35: 531–535, 1997.
1997 Kluwer Academic Publishers. Printed in Belgium.
Isolation, characterization and molecular cloning of a leaf-speciﬁc lectin
from ramsons (Allium ursinum L.).
, Els J.M. Van Damme
and Willy J. Peumans
Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Willem de Croylaan 42,
3001 Leuven, Belgium (
author for correspondence);
Center for Human Genetics, Katholieke Universiteit
Leuven, Herestraat 49, 3001 Leuven, Belgium
Received 16 October 1996; accepted in revised form 19 June 1997
Key words: Allium, leaf-speciﬁc, lectin, ramsons
Lectins were isolated from roots and leaves of ramsons and compared to the previously described bulb lectins.
Biochemical analyses indicated that the root lectins AUAIr and AUAIIr are identical to the bulb lectins AUAI
and AUAII, whereas the leaf lectin AUAL has no counterpart in the bulbs. cDNA cloning conﬁrmed that the leaf
lectin differs from the bulb lectins. Northern blot analysis further indicated that the leaf lectin is tissue-speciﬁcally
expressed. Sequence comparisonsrevealed that the ramsons leaf lectin differs considerably from the leaf lectins of
garlic, leek, onion and shallot.
Abbreviations: Abbreviations: ASAL, Allium sativum leaf agglutinin; AUAI, Allium ursinum bulb agglutinin
I; AUAII, Allium ursinum bulb agglutinin II; AUAL, Allium ursinum leaf agglutinin; AUAIr, Allium ursin-
um root agglutinin I; AUAIIr, Allium ursinum root agglutinin II; LECASAL, cDNA clone encoding ASAL;
LECAUAG1/LECAUAG2, LECAUAG0, LECAUAL, cDNA clones encoding AUAI, AUAII and AUAL, respect-
ively; PB, 50 mM sodium phosphate buffer (pH 7.0) containing 0.2 M NaCl.
Biochemical and molecular biological studies have
demonstratedthat numerousspecies of the plant genus
Allium contain one or more mannose-speciﬁc lectins
[4, 8, 10, 11]. Based on their molecular structure and
amino acid sequences, all Allium lectins clearly belong
to the superfamily of monocot mannose-binding lect-
ins, which besides in Alliaceae also occur in species
of the families Amaryllidaceae [6, 7, 9], Orchidaceae
,Liliaceae[1, 14, 15] andAraceae.Molecular
cloning of cDNAs encoding the agglutinins from leek,
onion, shallot , garlic [4, 8] and ramsons 
indicated that there are some important differences
between the different Allium lectins. Two subgroups
can be distinguished based on sequence similarities
and biological activities of the lectins. A ﬁrst subgroup
The nucleotide sequence data reported will appear in the Gen-
Bank and EMBL Nucleotide Sequence Databases under the acces-
sion number U68531.
comprises the leaf and root lectins from onion, leek,
shallot and garlic. They are highlyhomologousto each
other and to the Amaryllidaceae lectins, and are potent
inhibitorsof animal and human retroviruses(e.g. HIV)
. Members of the second subgroup comprising the
bulb agglutinins from garlic and ramsons share less
sequence similarity with each other. In addition, they
exhibit a low similarity to the ﬁrst subgroup and are
devoid of antiviral activity. Another important differ-
ence between the two subgroupsof Allium lectins con-
cerns their abundance and distribution over the plant.
The leaf and root lectins from onion, leek, shallot and
garlic are minor proteins in the respective tissues. In
contrast, the garlic and ramsons bulb lectins are pre-
dominant proteins but are strictly conﬁned to the bulb
tissue. It has been suggested that the genes encoding
the bulb lectins of garlic and ramsons diverged from
the main group of Alliaceae lectin genesto fulﬁll a role
Gr.: 201001125, PIPS Nr. 143823 BIO2KAP
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