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.
