What are the contributions of cytokinins, abscisic acid and sugars in bud outgrowth regulation by light intensity in rose?

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What are the contributions of cytokinins, abscisic acid and sugars in bud outgrowth regulation by light

intensity in rose?

Adrien Corot, Hanaé Roman, Jessica Bertheloot, Nathalie Leduc, Soulaiman Sakr, Sabine Demotes-Mainard

To cite this version:

Adrien Corot, Hanaé Roman, Jessica Bertheloot, Nathalie Leduc, Soulaiman Sakr, et al.. What are the contributions of cytokinins, abscisic acid and sugars in bud outgrowth regulation by light intensity in rose?. VII International Symposium on Rose Research and Cultivation, Jul 2017, Angers, France.

INRA, 2017, VII International Symposium on Rose Research and Cultivation July 2-7, 2017 Angers (France) Abstract book. �hal-01851779�

ABA antagonizes CK effect

Experimental treatments

What are the contributions of cytokinins, abscisic acid and sugars in bud outgrowth regulation by light intensity in rose?

Adrien Corot, Hanaé Roman, Jessica Bertheloot, Nathalie Leduc, Soulaiman Sakr and Sabine Demotes-Mainard

In ornamentals, particularly in rose, the visual aspect of a plant is an important element of its quality. In rose bush, the visual quality depends notably on plant shape and varies with branching. Bud outgrowth is controlled by a network of interacting hormones and sugars. Light environment strongly impacts branching, notably low light intensity decreases bud outgrowth. However, the mechanisms by which the light intensity affects bud outgrowth is still poorly understood. Here we study how sugars and two hormones, cytokinins (CK) and abscisic acid (ABA), mediate the light intensity regulation of the bud outgrowth pattern along an axis in an intact plant.

Cutting Floral

stage (T0)

+8 Days

H HL

H

L

H :

High light intensity

(540µE) L :

Low light intensity

(90µE)

• This study provides evidence that light intensity regulates bud outgrowth pattern in intact rose plants by regulating stem CK and ABA content. Although low light intensity reduced stem sugar content, this drop does not seem to have triggered bud outgrowth inhibition.

Prospects:

• Investigating at the transcriptomic level how cytokinins and abscisic acid regulate bud outgrowth pattern in response to light intensity.

H

1 3

5 7

2 4 6

8

1 3 5 7

2

4 6 8

0 10 20 30 40 50 60 70

HH-HL HH HL HH HL

T0 T4 T8

mg.g -1 for dry matter

Sucrose

ab

a

b

a

b

0%

20%

40%

60%

80%

100%

1 2 3 4 5 6 7 8

Bud outgr owth

Bud location from the top Mannitol

Suc_50mM Suc_100mM Suc_200mM Suc_300mM

This project was conducted within the regional program “RFI Objectif Végétal”, supported by the French Region Pays de la Loire, Angers Loire Métropole and the European Regional Development Fund

[email protected] , [email protected] Figure 3:Sucrose content of the fourth internode at floral

stage(T0), four (T4) and height (T8) days after floral stage.

Figure 7: ABA content of the fourth internode at floral stage(T0), four (T4) and height (T8) days after floral stage.

HH

HL ^0%

20%

40%

60%

80%

100%

1 2 3 4 5 6 7 8

Bud ou tgr owth

Bud location from the top HH HL

a

b

Figure 2: Frequency of bud outgrowth along the axis in HH and HL

Figure 1: Schematic representation of light treatments

• At 8 days:

- in HH the four most apical buds grow out

- in HL only the three most apical buds grow out - Bud 4 displays the most contrasted behavior : 100% vs 0% outgrowth in HH and LH, respectively

0 10 20 30 40 50

HH-HL HH HL HH HL

T0 T4 T8

ng.g -1 for dry matter

Cytokinin

d

a

b

c a

0%

20%

40%

60%

80%

100%

0 1 2 3 4 5 6 7 8

Bud outgr owth

Bud location from the top

Témoin Cks_500 µM

a

a b

b

Control

CK

CK

Figure 8: Bud outgrowth along the axis with CK (BAP) 500 µM supplied continuously with or without ABA by cotton wick in HL.

Figure 4: Bud outgrowth along the axis with sugars supplied continuously by cotton wick in HL.

Figure 6: Bud outgrowth along the axis with synthetic cytokinins (BAP) 500µM supplied continuously by cotton wick in HL.

Conclusions Introduction

UMR 1345 IRHS, INRA, AGROCAMPUS-Ouest, Université d’Angers, SFR 4207 QUASAV, Beaucouzé F-49071, France

HL inhibits bud outgrowth

Figure 5: Cytokinin content of the fourth internode at floral stage(T0), four (T4) and height (T8) days after floral stage. .

HL decreases sugar content near bud 4 HL decreases cytokinin content near bud 4 HL maintains high ABA content near bud 4

0 2 000 4 000 6 000 8 000 10 000 12 000

HH-HL HH HL HH HL

T0 T4 T8

ng.g -1 for dry matter

Abscisic Acid

a a

bc

ab c

0%

20%

40%

60%

80%

100%

0 1 2 3 4 5 6 7 8

Bud outgr owth

Bud location from the top

CK

CK_ABA_1,25mM CK_ABA_5mM a

b

c

CK supply releases the inhibition + CK

Suc. supply has no effect

Bud 4 Leaf 4

Cotton wick

+

Internode 4

Cotton wick Leaf 4

Bud 4 Bud 4

Leaf 4

Cotton wick

+ Internode 4 ^{Cotton wick}

Leaf 4

Bud 4

+ Suc + CK

Bud 4 Leaf 4

Cotton wick

+

Internode 4

Cotton wick Leaf 4

Bud 4

+ CK +

ABA