Potential Association of Reactive Oxygen Species With Male Sterility in Peach.

Yaming Cai,Collins Otieno Ogutu,Beibei Zheng,Zhishen Ma,Lei Zhao,Lu Wang,Yuepeng Han,Ruoxi Zhang,Liao Liao

doi:10.3389/fpls.2021.653256

Abstract

Male sterility is an important agronomic trait for hybrid vigor utilization and hybrid seed production, but its underlying mechanisms remain to be uncovered. Here, we investigated the mechanisms of male sterility in peach using a combined cytology, physiology, and molecular approach. Cytological features of male sterility include deformed microspores and tapetum cells along with absence of pollen grains. Microspores had smaller nucleus at the mononuclear stage and were compressed into belts and subsequently disappeared in the anther cavity, whereas tapetum cells were swollen and vacuolated, with a delayed degradation to flowering time. Male sterile anthers had an ROS burst and lower levels of major antioxidants, which may cause abnormal development of microspores and tapetum, leading to male sterility in peach. In addition, the male sterility appears to be cytoplasmic in peach, which could be due to sequence variation in the mitochondrial genome. Our results are helpful for further investigation of the genetic mechanisms underlying male sterility in peach.

Highlights

A typical flower has four types of floral organs: sepal, petal, stamen, and pistil
Our results indicated that abnormal development of tapetum and microspores are caused by disruption of reactive oxygen species (ROS) homeostasis, resulting in male sterility
This study reports for the first time the cytological and physiological traits associated with male sterility in peach

Summary

Introduction

A typical flower has four types of floral organs: sepal, petal, stamen, and pistil. The function of the flower is to make seeds for plant propagation. Seed development is initiated by fertilization in which male and female gametes fuse, with the former produced in the anther, a part of stamen, whereas the latter is produced in the ovary, an interior part of the pistil. The development of male and female gametes is crucial for reproduction of flowering plants. Some plants lack male gametes, called pollen grains, despite having complete floral organs. The pollen mother cell in the pollen sac undergoes meiotic division to produce four daughter cells that are called a tetrad. The microspores undergo a mitotic division, producing a larger vegetative cell and a smaller generative cell. Most angiosperms, such as lily, cotton, peach, and orange, have bicellular

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