Tapetum determinant1 is required for cell specialization in the Arabidopsis anther.
In flowering plants, pollen formation depends on the differentiation and interaction of two cell types in the anther: the reproductive cells, called microsporocytes, and somatic cells that form the tapetum. The microsporocytes generate microspores, whereas the tapetal cells support the development of microspores into mature pollen grains. Despite their importance to plant reproduction, little is known about the underlying genetic mechanisms that regulate the differentiation and interaction of these highly specialized cells in the anther. Here, we report the identification and characterization of a novel tapetum determinant1 (TPD1) gene that is required for the specialization of tapetal cells in the Arabidopsis anther. Analysis of the male-sterile mutant, tpd1, showed that functional interruption of TPD1 caused the precursors of tapetal cells to differentiate and develop into microsporocytes instead of tapetum. As a results, extra microsporocytes were formed and tapetum was absent in developing tpd1 anthers. Molecular cloning of TPD1 revealed that it encodes a small protein of 176 amino acids. In addition, tpd1 was phenotypically similar to excess microsporocytes1/extra sporogenous cells (ems1/exs) single and tpd1 ems1/exs double mutants. These data suggest that the TPD1 product plays an important role in the differentiation of tapetal cells, possibly in coordination with the EMS1/EXS gene product, a Leu-rich repeat receptor protein kinase.
Yang
Shu-Lan
SL
Institute of Molecular and Cell Biology, Singapore 117609.
Xie
Li-Fen
LF
Mao
Hui-Zhu
HZ
Puah
Ching San
CS
Yang
Wei-Cai
WC
Jiang
Lixi
L
Sundaresan
Venkatesan
V
Ye
De
D
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C483722:Tapetum determinant1 protein, Arabidopsis; C464786:At5g07280 protein, Arabidopsis