Plant Cell Monogr (9)
D.P.S. Verma and Z. Hong: Cell Division Control in Plants
DOI 10.1007/7089_2007_136/Published online: 24 July 2007
©Springer-Verlag Berlin Heidelberg 2007
Genetic Control of Anther Cell Division and Differentiation
Carey L. H. Hord1,2,3·HongMa1,2()
(^1) Department of Biology, The Pennsylvania State University,
University Park, PA 16802, USA
[email protected]
(^2) The Intercollege Graduate Program in Plant Biology, The Huck Institutes of Life
Sciences, The Pennsylvania State University, University Park, PA 16802, USA
(^3) Present address:
3015 Quinby Dr. Columbus, OH 43232, USA
AbstractAnther development requires the coordinated differentiation of several cell
types. Recent molecular genetic analyses have led to exciting advances in our understand-
ing of anther cell division and differentiation. TheSPOROCYTELESS/NOZZLE(SPL/NZZ)
gene is a putative transcription factor critical for early anther cell division and/or dif-
ferentiation. Several genes that regulate tapetum formation and differentiation have
been isolated, includingEXCESS MICROSPOROCYTES1/EXTRA SPOROGENOUS CELLS
(EMS1/EXS),SOMATIC EMBRYOGENESIS1(SERK1),SERK2,andTA PET UM D ET E R M I -
NANT1(TPD1). Also, genes important for normal tapetum differentiation and function
have been uncovered, including two closely related MYB genes,MYB33andMYB65,
which are post-transcriptionally regulated by microRNAs, and the riceUdt1gene. Finally,
genes encoding putative transcription regulators,ABORTED MICROSPORES(AMS)and
MALE STERILITY1(MS1), and a lipid metabolism enzyme,AtGPAT1are important for
pollen development. These discoveries have ushered in a new era for understanding the
control of cell division and differentiation during plant male reproductive development.
1
Introduction
Flowering plants rely on microsporogenesis and microgametogenesis for
male reproduction and the propagation of the species (Li and Ma 2002; Ma
2005). Microsporogenesis is the formation of the microspores that precedes
the development of the male gametophytes (pollen). Microgametogenesis oc-
curs within the developing pollen grain and leads to the generation of sperm
cells. These complex processes require coordinated development of sporo-
phytic and gametophytic cell types within the anther. InArabidopsis,thean-
ther cross section is butterfly-shaped, with two adaxial and two abaxial lobes.
At early stages, the development of the adaxial lobes lags behind slightly that
of the abaxial lobes. Anther development inArabidopsishas been divided into
14 stages on the basis of the anther morphology (Sanders et al. 1999) and
additional features can be detected using transmission electron microscopy
(TEM) (Owen and Makaroff 1995) (Table 1).