Plant Molecular Biology 35: 393–405, 1997.
1997 Kluwer Academic Publishers. Printed in Belgium.
Characterization of Phaseolus vulgaris cDNA clones responsive to water
deﬁcit: identiﬁcation of a novel late embryogenesis abundant-like protein
e M. Colmenero-Flores, Francisco Campos, Alejandro Garciarrubio and
Alejandra A. Covarrubias
Departmento de Biologia Molecular de Plantas, Instituto de Biotecnolog
ia, Universidad Nacional Aut
exico, Apdo. Postal 510-3, Cuernavaca, Morelos 62250, M
author for correspondence)
Received 31 October 1996; accepted in revised form 20 May 1997
Key words: Phaseolus vulgaris, water-deﬁcit genes, late embryogenesis-abundant proteins, proline-rich proteins,
lipid transfer proteins, low-molecular-weight heat shock proteins
Six cDNA clones from Phaseolus vulgaris, whose expression is induced by water deﬁcit and ABA treatment (rsP
cDNAs) were identiﬁed and characterized. The sequence analyses of the isolated clones suggest that they encode
two types of late-embryogenesis abundant (LEA) proteins, a class-1 cytoplasmic low-molecular-weight heat shock
protein (lmw-HSP), a lipid transfer protein (LTP), and two different proline-richproteins (PRP). One of the putative
LEA proteins identiﬁed correspondsto a novel9.3 kDa LEA-like protein. During the plant response to a mild water
35 MPa) all genes identiﬁed present a maximal expression at around 16 or 24 h of treatment,
followed by a decline in expression levels. Rehydration experiments revealed that those genes encoding PRPs and
LTP transiently re-induce or maintain their expression when water is added to the soil after a dehydration period.
This is not the case for the lea genes whose transcripts rapidly decrease, reaching basal levels a few hours after
rehydration (4 h). Under water deﬁcit and ABA treatments, the highest levels of expression for most of the genes
occur in the root, excluding the ltp gene whose maximum expression levels are found in the aerial regions of the
plant. This indicatesthat for these genes, both water deﬁcit and ABA-dependentexpression are under organ-speciﬁc
control. The data presented here support the importance of these proteins during the plant response to water deﬁcit.
Water deﬁcit is one of the most common environment-
al stress factors experiencedby soil plants. It interferes
with both normal development and growth and has a
major adverse effect on plant productivity. Among a
diversity of responses, plants adapt to water deﬁcit
by the induction of speciﬁc genes (reviewed in ).
Some of these genes are also expressed during the nor-
mal embryogenesisprogram when seeds desiccate and
embryos become dormant . During this develop-
mental stage, plant tissues are viable for long periods
The nucleotide sequence data reported will appear in the
EMBL, GenBank and DDBJ Nucleotide Sequence Databases under
the accession numbers U72764 (PvPRP-12), U72765 (PvLTP-24),
U72766 (PvHSP17-19), U72767 (PvLEA4-25), U72768 (PvPRP2-
37) and U72769 (PvPrp-12).
of time in conditions of extremely high dehydration.
Both environmentaland developmentalprocesses have
in common the mediation of the phytohormone abscis-
ic acid (ABA) [8, 51, reviewed in 9]. The applicationof
ABA to unstressed vegetative tissues can mimic many
effects of drought on plants, including the induction
of water deﬁcit-responsive genes [51, reviewed in 9].
In recent years, efforts have been focused toward the
isolation of genes that are induced during water deﬁ-
cit or ABA treatment in order to study the function of
their products. This approach has made possible the
identiﬁcation of stress proteins and the characteriza-
tion of their biochemical, cellular and adaptive roles in
osmotic stressed plant cells. This is the case of proteins
implicated in the biosynthesis of osmolytes (reviewed
in [4, 29]), in the uptake and compartmentation of ions
[42, 43], in hydroxyl-radical scavenging [4, 48], and
Gr.: 201001113, PIPS Nr. 142176 BIO2KAP
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