Plant Molecular Biology 37: 607–619, 1998.
1998 Kluwer Academic Publishers. Printed in Belgium.
Identiﬁcation, sequence analysis and expression studies of novel
anther-speciﬁc genes of Arabidopsis thaliana
and Hong Ma
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA (
author for correspondence);
University of New York at Stony Brook, Stony Brook, NY 11794, USA
Received 18 September 1997; accepted in revised form 30 December 1997
Key words: anther expression, Arabidopsis, cDNAs, in situ hybridization
Relatively little is known about pollen development at the molecular level. For the purpose of gaining understanding
of the molecular control of pollen development, a number of Arabidopsis cDNA fragments were isolated using
subtractive hybridizations. DNA and RNA hybridizations and sequence analyses indicate that we have isolated
cDNAs representing 13 genes. Sequences for 8 of these genes are novel, while those for the remaining 5 genes have
substantial similarity to genes previously reported as anther- or pollen-speciﬁc. RNA in situ hybridizations with
5 genes revealed that four of them are tapetum-speciﬁc with differing temporal expression patterns during pollen
development and one is pollen-speciﬁc within the ﬂower. Sequence analysis of full-length cDNAs showed that one
of the novel genes, ATA7, encodes a protein related to lipid transfer proteins. Another gene, ATA20, encodes a
protein with novel repeat sequences and a glycine-rich domain that shares a predicted structure with a known cell
wall protein. The full-length ATA27 cDNA encodes a protein similar to the BGL4
-glucosidase from Brassica
napus. The ATA27 protein is predicted to have an ER retention signal and an acidic isoelectric point, suggesting
that it may be localized to the ER lumen. This may be a means of compartmentalization from its substrate(s). Our
studies demonstrate that subtractive hybridizations can be used to identify previously unknown genes, which should
be valuable tools for further study of pollen and anther development and function.
The plant life cycle includes multicellular haploid
structures called gametophytes, within which the pro-
duction of gametes takes place. In higher plants, gam-
etophytes form within the reproductive ﬂoral organs,
the stamens and pistil. These also contain many differ-
entiated tissues and cells [17, 18]. It is of great interest
to learn what molecular mechanisms control develop-
ment of the stamen, pistil and gametophytes.
The developmental stages of the male gametophyte
(pollen) have been reviewed previously . Premei-
otic diploid precursor cells, called microspore mother
cells, undergo meiosis to produce tetrads each with
The nucleotide sequence data reportedwill appear in the EMBL,
GenBank and DDBJ Nucleotide Sequence Databases under the
accession numbers AF037589 (ATA7), AF037362 (ATA20)and
four microspores. Microspores are then separated, and
become vacuolated. The microspore then undergoes
an asymmetric mitosis (pollen mitosis I), resulting
in a vegetative (large) and a generative (small) cell.
The vegetative cell later during pollination extends
the pollen tube. The generative cell divides again
(pollen mitosis II) to produce two sperm cells .
Normal pollen development relies on healthy tapetum
cells that surround microspore mother cells and early
microspores . The tapetum cells synthesize pro-
teins, lipids, and ﬂavonoids that are deposited on the
microspores and comprise the outer strata of the pollen
wall, the exine and tryphine layers .
One way in which stamen and pollen development
have been studied is through the isolation of cDNAs
representing stamen-speciﬁc or -predominantmRNAs,
followed by functional characterization of these genes
by inhibiting expression with antisense RNA, or by