Plant Molecular Biology 35: 433–442, 1997.
1997 Kluwer Academic Publishers. Printed in Belgium.
Two growth-related organ-speciﬁc cDNAs from Cicer arietinum epicotyls
Francisco J. Mu
noz, Berta Dopico and Emilia Labrador
Departamento de Biolog
ia Vegetal (Fisiolog
ia Vegetal), Universidad de Salamanca, Avda. Campo Charro S/n,
37008 Salamanca, Spain (
author for correspondence)
Received 19 December 1996; accepted in revised form 23 May 1997
Key words: chickpea, epicotyls, growth, tissue-speciﬁc gene expression
Two cDNAs, CanST-1 and CanST-2, encoding two different growth-related organ-speciﬁc sequences have been
isolated from a cDNA library from growing epicotyls of Cicer arietinum. An intriguing property of these two
clones is the presence in their coding region of a repeated sequence which is highly conserved except for the
number of repeats. The corresponding genes of CanST-1 and CanST-2 encode for proteins related to elongation
processes. CanST-1 and CanST-2 are up-regulated during epicotyl growth, the transcript levels of both clones
decrease when the growth of epicotyls is inhibited by several treatments and their expression increases when
epicotyls resume growth. Furthermore, clones CanST-1 and CanST-2 are tissue-speciﬁc and are only expressed in
epicotyls, mesocotyls, roots and stem tissues whose cells undergo elongation processes. Neither clone was found
to be expressed in other organs such as cotyledons, leaves, ﬂowers, pods and immature seeds. The results of auxin
(IAA) and brassinolides (BR) treatments suggest that the processes in which the proteins encoded by CanST-1 and
CanST-2 are involved are not mediated by these hormones.
Plant cell growth is a highly complex process funda-
mental to plant development that requires the products
of many genes taking part in numerous life processes.
Thesegeneswillbeactivatedor repressed asa function
of cellular needs at any given moment with a temporal
and spatial regulation. The mechanisms of the regu-
lation of genes involved in growth are not clear and
many aspects remain to be elucidated.
Throughout plant growth, the differential expres-
sion of a number of genes occurs. The products of
these genes may participate in speciﬁc processes that
guarantee the correct plant development. In the same
way, factors that modify growth either positively or
In this sense, some growth regulation substances such
as IAA [1, 15], giberellins  or brassinolides (BR)
Thenucleotidesequencedatareportedwillappearin the EMBL,
GenBank and DDBJ Nucleotide Sequence Databases under the
accession numbers X97454 (CanST-1) and X97455 (CanST-2).
 induce the expression of a whole array of speciﬁc
To understand plant cell growth, it is necessary to
isolate and characterisize the genes that are speciﬁc
to growing tissues as well as to study genes speciﬁc
to certain developmental stages. In the former case,
the idea is to identify genes that are expressed only or
mostly during active phases of growth and that show
little or no expression in tissues with low or no growth.
In the present work our aim was to isolate growth-
related clonesfrom a cDNA library from Cicer arietin-
um epicotyls in the active phase of elongation(5 days)
and to characterize them. The differential expression
of the genes corresponding to these clones in differ-
ent developmental stages, different organs and under
different growth conditions could afford an idea of the
possiblefunctionplayedby the correspondingproteins
along the complex process of growth.
Gr.: 201001111, PIPS Nr. 141403 BIO2KAP
plan3786.tex; 21/08/1997; 7:19; v.7; p.1