IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Regulation of cell cycle activity in the embryo of barley seeds during germination as related to grain hydration
Autor/es:
GENDREAU E, ROMANIELLO S, BARAD S, LEYMARIE L, BENECH-ARNOLD R AND CORBINEAU F.
Revista:
JOURNAL OF EXPERIMENTAL BOTANY
Editorial:
Oxford Journals
Referencias:
Lugar: Oxford; Año: 2008 vol. 59 p. 203 - 212
ISSN:
0022-0957
Resumen:
Various studies indicate that cell division is a postgermination
phenomenon, with radicle protrusion occurring
by cell elongation, while others demonstrate
that induction of the cell cycle occurs in osmoconditioned
seeds prior to radicle growth. The aim of
the present work was to investigate the occurrence of
the cell cycle during germination as related to grain
hydration, using: (i) a flow cytometry technique to
estimate the percentage of cell nuclei in G1 and G21 and G2
phases of the cell cycle; and (ii) reverse transcription-
PCR (RT-PCR) in order to characterize the expression
of the genes encoding cyclin-dependent kinases
(CDKA1, CDKB1, and CDKD1) and cyclins (CYCA3,CDKA1, CDKB1, and CDKD1) and cyclins (CYCA3,
CYCB1, and CYCD4), the main genes involved in the
cell cycle and its regulation. Radicle tips of embryos
were isolated from seeds placed for various times on
water at 30 C and from grains partially hydrated at
moisture contents ranging from 11% to 51% fresh
weight (FW), which prevent radicle elongation. Abscisic
acid (ABA) contents of the embryos during seed
germination at 30 C and after 48 h of partial hydration
were also measured. In dry embryos, cells are mostly
arrested in the G1 phase of the cell cycle (82%), the
remaining cells being in the G2 phase, and the ABA
content of the embryo was 432.7 ng g21 dry weight
(DW). Seed imbibition was associated with a sharp
decrease in ABA content as early as 5 h, while the cell
cycle reactivation was a late process taking place, and CYCD4), the main genes involved in the
cell cycle and its regulation. Radicle tips of embryos
were isolated from seeds placed for various times on
water at 30 C and from grains partially hydrated at
moisture contents ranging from 11% to 51% fresh
weight (FW), which prevent radicle elongation. Abscisic
acid (ABA) contents of the embryos during seed
germination at 30 C and after 48 h of partial hydration
were also measured. In dry embryos, cells are mostly
arrested in the G1 phase of the cell cycle (82%), the
remaining cells being in the G2 phase, and the ABA
content of the embryo was 432.7 ng g21 dry weight
(DW). Seed imbibition was associated with a sharp
decrease in ABA content as early as 5 h, while the cell
cycle reactivation was a late process taking placeC and from grains partially hydrated at
moisture contents ranging from 11% to 51% fresh
weight (FW), which prevent radicle elongation. Abscisic
acid (ABA) contents of the embryos during seed
germination at 30 C and after 48 h of partial hydration
were also measured. In dry embryos, cells are mostly
arrested in the G1 phase of the cell cycle (82%), the
remaining cells being in the G2 phase, and the ABA
content of the embryo was 432.7 ng g21 dry weight
(DW). Seed imbibition was associated with a sharp
decrease in ABA content as early as 5 h, while the cell
cycle reactivation was a late process taking placeC and after 48 h of partial hydration
were also measured. In dry embryos, cells are mostly
arrested in the G1 phase of the cell cycle (82%), the
remaining cells being in the G2 phase, and the ABA
content of the embryo was 432.7 ng g21 dry weight
(DW). Seed imbibition was associated with a sharp
decrease in ABA content as early as 5 h, while the cell
cycle reactivation was a late process taking place1 phase of the cell cycle (82%), the
remaining cells being in the G2 phase, and the ABA
content of the embryo was 432.7 ng g21 dry weight
(DW). Seed imbibition was associated with a sharp
decrease in ABA content as early as 5 h, while the cell
cycle reactivation was a late process taking place2 phase, and the ABA
content of the embryo was 432.7 ng g21 dry weight
(DW). Seed imbibition was associated with a sharp
decrease in ABA content as early as 5 h, while the cell
cycle reactivation was a late process taking place21 dry weight
(DW). Seed imbibition was associated with a sharp
decrease in ABA content as early as 5 h, while the cell
cycle reactivation was a late process taking place
;46 h prior to radicle protrusion. Hydration of seeds
resulted in a decrease in embryo ABA content, but it
remained at a high level (207273 ng g21 DW) even
after 48 h at 0.410.51 g H2O g21 FW. The cell population
of the radicle tips in the G2 phase of the cell cycle,
i.e. 4C nuclei, increased from 9% up to 34% at
a moisture content of 51% FW. In dry seeds, CDKA146 h prior to radicle protrusion. Hydration of seeds
resulted in a decrease in embryo ABA content, but it
remained at a high level (207273 ng g21 DW) even
after 48 h at 0.410.51 g H2O g21 FW. The cell population
of the radicle tips in the G2 phase of the cell cycle,
i.e. 4C nuclei, increased from 9% up to 34% at
a moisture content of 51% FW. In dry seeds, CDKA121 DW) even
after 48 h at 0.410.51 g H2O g21 FW. The cell population
of the radicle tips in the G2 phase of the cell cycle,
i.e. 4C nuclei, increased from 9% up to 34% at
a moisture content of 51% FW. In dry seeds, CDKA12O g21 FW. The cell population
of the radicle tips in the G2 phase of the cell cycle,
i.e. 4C nuclei, increased from 9% up to 34% at
a moisture content of 51% FW. In dry seeds, CDKA12 phase of the cell cycle,
i.e. 4C nuclei, increased from 9% up to 34% at
a moisture content of 51% FW. In dry seeds, CDKA1CDKA1
and CDKD1 mRNAs were present at low levels, but
transcripts of CDKB1, CYCA3, CYCB1, and CYCD4CDKD1 mRNAs were present at low levels, but
transcripts of CDKB1, CYCA3, CYCB1, and CYCD4CDKB1, CYCA3, CYCB1, and CYCD4
were not detected. Radicle protrusion was associated
with a higher expression of CDKA1, CDKB1, CYCA3,
and CYCB1. Blockage of germination of partially
hydrated grains resulted in a reduction in the expression
of CDKA1 and CDKB1, and of CYCA3 and CYCB1,
and in a reinforcement of that of CDKD1 and CYCD4.
Patterns of gene expression show differential sensitivity
of the genes studied to hydration of the grain. They
will be discussed with regard to embryo ABA content
and embryo sensitivity to ABA.CDKA1, CDKB1, CYCA3,
and CYCB1. Blockage of germination of partially
hydrated grains resulted in a reduction in the expression
of CDKA1 and CDKB1, and of CYCA3 and CYCB1,
and in a reinforcement of that of CDKD1 and CYCD4.
Patterns of gene expression show differential sensitivity
of the genes studied to hydration of the grain. They
will be discussed with regard to embryo ABA content
and embryo sensitivity to ABA.CYCB1. Blockage of germination of partially
hydrated grains resulted in a reduction in the expression
of CDKA1 and CDKB1, and of CYCA3 and CYCB1,
and in a reinforcement of that of CDKD1 and CYCD4.
Patterns of gene expression show differential sensitivity
of the genes studied to hydration of the grain. They
will be discussed with regard to embryo ABA content
and embryo sensitivity to ABA.CDKA1 and CDKB1, and of CYCA3 and CYCB1,
and in a reinforcement of that of CDKD1 and CYCD4.
Patterns of gene expression show differential sensitivity
of the genes studied to hydration of the grain. They
will be discussed with regard to embryo ABA content
and embryo sensitivity to ABA.CDKD1 and CYCD4.
Patterns of gene expression show differential sensitivity
of the genes studied to hydration of the grain. They
will be discussed with regard to embryo ABA content
and embryo sensitivity to ABA.
Key words: Abscisic acid, barley, cell cycle,