Ultrastructural localization of polygalacturonase in ethylene-stimulated abscission of tomato pedicel explants.

Ming-Fang Qi,Tao Xu,Tian-Lai Li,Wei-Zhi Chen

doi:10.1155/2014/389896

Abstract

Polygalacturonase (PG) is crucial in plant organ abscission process. This paper investigated the cellular and subcellular localization of PG in ethylene-stimulated abscission of tomato pedicel explants. Confocal laser scanning microscopy of abscission zone sections with the fluorescent probe Cy3 revealed that PG was initially accumulated in parenchyma cells in cortical and vascular tissues after 8 h of ethylene treatment and then extended throughout the abscission zone when the abscission zone separated at 24 h after ethylene treatment. At the subcellular level, transmission electron microscopy with immunogold staining showed that PG showed abundant accumulation in the cortical and vascular tissues at 8 h after ethylene treatment, and the distribution area extended to the central parenchyma cells at 16 h after ethylene treatment. In addition, PGs were observed in the distal and proximal parts of the tomato pedicel explants throughout the abscission process. The results provided a visualized distribution of PG in the pedicel abscission zone and proved that PG was closely related to abscission.

Highlights

Abscission is the process in which organs are separated from the parent plant; this process involves multiple changes in cell structure, metabolism, and gene expression [1]
The results clearly demonstrated the distribution of PG in the tomato pedicel abscission zone after immunogold staining
Cell wall Gold to demonstrate antigens by electron microscopy, various modifications have helped improve the sensitivity of the method, which has become a mature technology in immunohistochemistry [16,17,18]

Summary

Introduction

Abscission is the process in which organs are separated from the parent plant; this process involves multiple changes in cell structure, metabolism, and gene expression [1]. Abscission usually occurs in the abscission zone of plants. The abscission zone contains small, square-shaped cells with a dense cytoplasm [2, 3]. Abscission has three classes, namely, normal abscission (such as abscission of ripened fruit and seed), metabolic abscission due to the completion of reproductive and vegetative growth (such as premature shedding of fruit and unpollinated flowers), and abscission due to environmental stresses (such as heat, cold, and light). The development and mechanisms of plant hormones, such as the interplay of ethylene and auxin, are well documented. Detailed mechanisms on the regulation and control of these processes remain unknown

Methods

Results

Conclusion