Morphological Features of the Anther Development in Tomato Plants with Non-Specific Male Sterility.

Inna A Chaban,Marat R Khaliluev,Liliya R Bogoutdinova,Ekaterina N Baranova,Neonila V Kononenko,Alexander A Gulevich

doi:10.3390/biology9020032

Abstract

The study was devoted to morphological and cytoembryological analysis of disorders in the anther and pollen development of transgenic tomato plants with a normal and abnormal phenotype, which is characterized by the impaired development of generative organs. Various abnormalities in the structural organization of anthers and microspores were revealed. Such abnormalities in microspores lead to the blocking of asymmetric cell division and, accordingly, the male gametophyte formation. Some of the non-degenerated microspores accumulate a large number of storage inclusions, forming sterile mononuclear pseudo-pollen, which is similar in size and appearance to fertile pollen grain (looks like pollen grain). It was discussed that the growth of tapetal cells in abnormal anthers by increasing the size and ploidy level of nuclei contributes to this process. It has been shown that in transgenic plants with a normal phenotype, individual disturbances are also observed in the development of both male and female gametophytes. The reason for the developmental arrest of some ovules was the death of endosperm at different stages of the globular embryo. At the same time, noticeable hypertrophy of endothelial cells performing a secretory function was observed. In the ovules of transgenic plants with abnormalities, the endothelium forms a pseudo-embryo instead of the embryo sac, stimulating the development of parthenocarpic fruits. The data obtained in this study can be useful for a better understanding of the genetic and molecular mechanisms of cytoplasmic male sterility and parthenocarpic fruit development in tomatoes.

Highlights

Pollen development is one of the most important processes in the life cycle of plants, since only normally formed pollen contributes to proper fertilization and the formation of full-fledged seeds and fruits
In the flowers of transgenic tomato plants with abnormalities, the pestle was noticeably larger compared to the control
The tomato plant was from the Solanum lycopersicum L. line YaLF and transgenic tomato plants expressing the ac gene, encoding chitin-binding protein were from Amaranthus caudatus L. with normal and abnormal phenotype, which was characterized by impaired development of generative organs

Summary

Introduction

Pollen development is one of the most important processes in the life cycle of plants, since only normally formed pollen contributes to proper fertilization and the formation of full-fledged seeds and fruits. Under adverse conditions or any effects on plants, violations primarily occur in the anther development, which leads to the formation of sterile pollen. Most studies focus on the genetic aspects of cytoplasmic male sterility (CMS). The process of pollen formation involves several stages and is regulated by a vast number of genes [1,2,3,4,5]. Numerous genes and proteins associated with the abortion of microspores and pollen [6,7] and the molecular mechanisms underlying various male sterile phenotypes have been characterized [6,8,9,10,11,12]. The morphological and cytological aspects of pollen sterility have not been investigated

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