Planta

, Volume 235, Issue 6, pp 1221–1237

Regulation of polyamine metabolism and biosynthetic gene expression during olive mature-fruit abscission

Authors

  • Jose A. Gil-Amado
    • Department of Plant PhysiologyUniversity of Extremadura
    • Department of Plant PhysiologyUniversity of Extremadura
Original Article

DOI: 10.1007/s00425-011-1570-1

Cite this article as:
Gil-Amado, J.A. & Gomez-Jimenez, M.C. Planta (2012) 235: 1221. doi:10.1007/s00425-011-1570-1

Abstract

Exogenous ethylene and some inhibitors of polyamine biosynthesis can induce mature-fruit abscission in olive, which could be associated with decreased nitric oxide production as a signaling molecule. Whether H2O2 also plays a signaling role in mature-fruit abscission is unknown. The possible involvement of H2O2 and polyamine in ethylene-induced mature-fruit abscission was examined in the abscission zone and adjacent cells of two olive cultivars. Endogenous H2O2 showed an increase in the abscission zone during mature-fruit abscission, suggesting that accumulated H2O2 may participate in abscission signaling. On the other hand, we followed the expression of two genes involved in the polyamine biosynthesis pathway during mature-fruit abscission and in response to ethylene or inhibitors of ethylene and polyamine. OeSAMDC1 and OeSPDS1 were expressed differentially within and between the abscission zones of the two cultivars. OeSAMDC1 showed slightly lower expression in association with mature-fruit abscission. Furthermore, our data show that exogenous ethylene or inhibitors of polyamine encourage the free putrescine pool and decrease the soluble-conjugated spermidine, spermine, homospermidine, and cadaverine in the olive abscission zone, while ethylene inhibition by CoCl2 increases these soluble conjugates, but does not affect free putrescine. Although the impact of these treatments on polyamine metabolism depends on the cultivar, the results confirm that the mature-fruit abscission may be accompanied by an inhibition of S-adenosyl methionine decarboxylase activity, and the promotion of putrescine synthesis in olive abscission zone, suggesting that endogenous putrescine may play a complementary role to ethylene in the normal course of mature-fruit abscission.

Keywords

Abscission zoneEthyleneMature-fruit abscissionPolyamineS-Adenosyl methionine decarboxylaseSpermidine synthase

Abbreviations

ACC

1-Aminocyclopropane-1-carboxylic acid

ACO

1-Aminocyclopropane-1-carboxylic acid oxidase

ACS

1-Aminocyclopropane-1-carboxylic acid synthase

ADC

Arginine decarboxylase

ARB

Arbequina cultivar

AZ

Abscission zone

AZ–AC

Abscission zone and adjacent cells

Cad

Cadaverine

CHA

Cyclohexylamine

CLSM

Confocal laser scanning microscopy

dcSAM

Decarboxylated S-adenosylmethionine

DCFH2-DA

Dichlorodihydrofluorescein diacetate

DAO

Diamine oxidase

EIL

EIN3-like gene

ET

Ethylene

FDF

Fruit-detachment force

HomoSpd sym

Homospermidine

HSS

Homospermidine synthase

MACC

(Malonyl)-ACC

MGBG

Methylglyoxalbis(guanylhydrazone)

NO

Nitric oxide

OeACS2

Olea europaea ACS 2

OeEIL2

Olea europaea EIL 2

OeSAMDC1

Olea europaea SAMDC 1

OeSPDS1

Olea europaea SPDS 1

ODC

Ornithine decarboxylase

PA

Polyamine

PAO

Polyamine oxidase

PIC

Picual cultivar

Put

Putrescine

ROS

Reactive oxygen species

SAM

S-Adenosylmethionine

SAMDC

S-Adenosylmethionine decarboxylase

Spd

Spermidine

SPDS

Spermidine synthase

Spm

Spermine

SPMS

Spermine synthase

Supplementary material

425_2011_1570_MOESM1_ESM.tif (784 kb)
Supplementary material 1 (TIFF 783 kb)
425_2011_1570_MOESM2_ESM.tif (783 kb)
Supplementary material 2 (TIFF 782 kb)

Copyright information

© Springer-Verlag 2011