Plant Cell Reports

, Volume 30, Issue 8, pp 1485–1492

Expression patterns of several floral genes during flower initiation in the apical buds of apple (Malus × domestica Borkh.) revealed by in situ hybridization

  • Naozumi Mimida
  • Ayano Ureshino
  • Norimitsu Tanaka
  • Narumi Shigeta
  • Noriko Sato
  • Yuki Moriya-Tanaka
  • Hiroshi Iwanami
  • Chikako Honda
  • Akira Suzuki
  • Sadao Komori
  • Masato Wada
Original Paper

Abstract

The apple (Malus × domestica Borkh.) is one of the commercially important fruit crops in the worldwide. The apple has a relatively long juvenile period (up to 4 years) and a long reproductive period between the flower initiation and the mature fruit (14–16 months), which prevent the fruit breeding. Therefore, the understanding of the flowering system is important to improve breeding efficiency in the apple. In this study, to examine the temporal and spatial expression patterns of the floral genes, MdTFL1, MdAP1 (MdMASD5),AFL2, and MdFT, we conducted in situ hybridization analysis in the apple shoot apex. In vegetative phase, MdTFL1 was expressed on the rib meristem zone. When vegetative meristem began converting into inflorescence meristem, the expression level of MdTFL1 was drastically decreased. At the early stage of inflorescence meristem, the expression levels of AFL2, MdFT, and MdAP1 were up-regulated in the leaf primordia and the upper region of cell layers on the shoot apex. In late stage, the expression levels of AFL2 and MdAP1 were up-regulated in the young floral primordia. At a more advanced stage, high expression of MdAP1 was observed in the inflorescence primordium through the inner layer of sepal primordia and the outer layer of receptacle primordia and floral axis. Our results suggest that AFL2, MdFT, and MdAP1 affect to convert from the vegetative meristem into the inflorescence meristem after the decline of MdTFL1 expression. After that, AFL2 and MdAP1 promote the formation of the floral primordia and floral organs.

Keywords

Apical meristem Apple Flowering gene Phase transition 

Abbreviations

AP1

APETALA1

CEN

CENTRORADIALIS

FT

FLOWERING LOCUS T

LFY

LEAFY

Md

Malus × domestica

PEBP

Phosphatidylethanolamine binding protein

RT–PCR

Reverse transcription-polymerase chain reaction

SOC1

SUPRESSOR OF OVEREXPRESSION OF CONSTANS1

TFL1

TERMINAL FLOWER1

UTR

Untranslational region

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Naozumi Mimida
    • 1
  • Ayano Ureshino
    • 2
  • Norimitsu Tanaka
    • 3
  • Narumi Shigeta
    • 1
  • Noriko Sato
    • 1
  • Yuki Moriya-Tanaka
    • 2
  • Hiroshi Iwanami
    • 2
  • Chikako Honda
    • 2
  • Akira Suzuki
    • 1
  • Sadao Komori
    • 1
  • Masato Wada
    • 2
  1. 1.Faculty of AgricultureIwate UniversityIwateJapan
  2. 2.Apple Breeding and Physiology Research TeamApple Research Station, National Institute of Fruit Tree ScienceIwateJapan
  3. 3.Faculty of Agriculture and Life ScienceHirosaki UniversityHirosakiJapan

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