Abstract
Two homeodomain leucine zipper (HD-Zip) genes were isolated and characterized from a cDNA library of the male flower buds of S. latifolia. Two genes, SlHDL1 and SlHDL2, encode proteins characterized as HD-Zip transcription factors. Seven cDNAs were isolated by cDNA subtraction of healthy male buds with the female buds infected with the dimorphic smut fungus Microbotryum violaceum. Five cDNAs are predicted to encode a chalcone-synthase-like protein, a glycosyl hydrolase family 17 protein, a proline-rich protein APG precursor, a strictosidine synthase family protein, and a mandelonitrile lyase protein. In situ hybridization showed that they are expressed in tapetum, tetrad and pollen grains between meiosis and microspore mitosis, timing that corresponds to a burst in tapetal activity in the developing anthers. The genes isolated will be useful for the isolation of tapetal-specific promoters, and revealing the interactions between the male-sterility restoration factor and the fertility related genes.
