In
Arabidopsis thaliana the
ANGUSTIFOLIA (
AN) gene regulates the width of leaves by controlling the diffuse growth of leaf cells in the medio‐lateral direction. In the genome of the moss
Physcomitrella patens, we found two normal
ANs (
PpAN1‐1 and
1‐2). Both
PpAN1 genes complemented the
A. thaliana an‐1 mutant phenotypes. An analysis of spatiotemporal promoter activity of each
PpAN1 gene, using transgenic lines that contained each
PpAN1‐promoter–
uidA (GUS) gene, showed that both promoters are mainly active in the stems of haploid gametophores and in the middle to basal region of the young sporophyte that develops into the seta and foot. Analyses of the knockout lines for
PpAN1‐1 and
PpAN1‐2 genes suggested that these genes have partially redundant functions and regulate gametophore height by controlling diffuse cell growth in gametophore stems. In addition, the seta and foot were shorter and thicker in diploid sporophytes, suggesting that cell elongation was reduced in the longitudinal direction, whereas no defects were detected in tip‐growing protonemata. These results indicate that both
PpAN1 genes in
P. patens function in diffuse growth of the haploid and diploid generations but not in tip growth. To visualize microtubule distribution in gametophore cells of
P. patens, transformed lines expressing
P. patens α‐tubulin fused to sGFP were generated. Contrary to expectations, the orientation of microtubules in the tips of gametophores in the
PpAN1‐1/1‐2 double‐knockout lines was unchanged. The relationships among diffuse cell growth, cortical microtubules and AN proteins are discussed.
相似文献