The role of CIL1 in <i>brassica carinata</i> lateral meristem development

• Main Author: Gibson, Shawn
• Other Authors: Wilson, Kenneth E.
• Format: Others
• Language: en
• Published: University of Saskatchewan 2005
• Subjects: cytokinin; catecholamine; phytohormone; auxin
• Online Access: http://library.usask.ca/theses/available/etd-08222005-115050/

A cDNA sequence representing a <i> Brassica carinata</i> gene the expression of which is induced by copper chloride treatment, was isolated from a library constructed with mRNA from treated leaves, and designated CIL1 (COPPER CHLORIDE INDUCED in LEAVES). A Basic Local Alignment Search Tool search revealed that CIL1 has similarities to an auxin-induced gene, AIR12 from <i>Arabidopsis thaliana</i>. Southern blot analysis of CIL1 in <i>B. carinata, B. nigra</i> and <i>B. oleracea</i> indicated that it is a member of a small multigene family. Antisense CIL1 transgenic plants were generated to investigate the function of CIL1, and the resulting transformants displayed increased secondary branching suggesting that CIL1 has a role in regulating hormone content or plant architecture. Results of induction studies indicate that the auxin analog a-naphthalene acetic acid, the cytokinin 6-benzylaminopurine, and +/- abscisic acid increase expression of CIL1. Seven CIL1 antisense lines were grown to the T4 generation and were confirmed homozygous. Analysis of CIL1 expression using real-time quantitative RT-PCR showed reduced expression in every examined line. Transgenic plants produced many leaves at the lateral meristems indicating a release of apical dominance. Additionally, the concentrations of auxins, cytokinins, and abscisic acid were altered in the roots and stems of transgenic plants compared to non-transformed plants. Therefore, CIL1 has a role in regulating hormone content that affects lateral meristem activity, apical dominance, and leaf production.