Role of COV in vascular patterning

The molecular mechanisms that control the ordered patterning of vascular tissue development in plant are not well understood. Several models propose a two component for plant vascular differentiation in which requires both an inducer of vascular tissue an also an inhibitory component that prevents the formation of vascular bundles near pre-existing bundles by a process often termed lateral inhibition. We have identified two recessive allelic mutants in Arabidopsis, designated continuous vascular (cov-1, cov-2), which display a dramatic increase in vascular tissue in the stem in place of the interfascicular region that normally separates the vascular bundles. The mutant plants exhibited normal vascular patterning in leaves and cotyledons. Analysis of the interaction of cov with known auxin signalling mutant and direct analysis of auxin concentrations suggests that cov affects vascular pattering by some mechanism that is independent of auxin. COV is expressed in all plant tissue but more highly in developing flowers and stems. The COV protein is predicted to be an integral membrane protein of unknown function, conserved in both plants and bacteria that is involved in negatively regulating the differentiation of the vascular tissue in the stem of Arabidopsis.The phenotype of COV exhibits some similarities to acl5 which is known to be a defect in the gene for spermidine synthase. Consequently, we are interested to test the idea that COV may be involved in the transport or perception of polyamines and that polyamines may be essential signals in normal vascular tissue development. Clearly, it this proves to be the case we would expect to see some differences in the transcript levels of genes associated with these pathways. Experimenter name = Simon Turner Experimenter phone = 0161 275 5751 Experimenter fax = 0161 275 3938 Experimenter address = University of Manchester Experimenter address = School of Biological Sciences Experimenter address = 3.614 Stopford building Experimenter address = Oxford Rd Experimenter address = Manchester Experimenter zip/postal_code = M13 9PT Experimenter country = UK Keywords: genetic_modification_design 8 samples were used in this experiment