The Major Factors Causing the Microspore Abortion of Genic Male Sterile Mutant NWMS1 in Wheat (Triticum aestivum L.).

Junhang An,Junchang Li,Huijuan Li,Hao Niu,Qiaoyun Li,Qiaoqiao Xu,Zhixin Jiao,Yumei Jiang,Jing Zhang,Jishan Niu

doi:10.3390/ijms20246252

Abstract

Male sterility is a valuable trait for genetic research and production application of wheat (Triticum aestivum L.). NWMS1, a novel typical genic male sterility mutant, was obtained from Shengnong 1, mutagenized with ethyl methane sulfonate (EMS). Microstructure and ultrastructure observations of the anthers and microspores indicated that the pollen abortion of NWMS1 started at the early uninucleate microspore stage. Pollen grain collapse, plasmolysis, and absent starch grains were the three typical characteristics of the abnormal microspores. The anther transcriptomes of NWMS1 and its wild type Shengnong 1 were compared at the early anther development stage, pollen mother cell meiotic stage, and binucleate microspore stage. Several biological pathways clearly involved in abnormal anther development were identified, including protein processing in endoplasmic reticulum, starch and sucrose metabolism, lipid metabolism, and plant hormone signal transduction. There were 20 key genes involved in the abnormal anther development, screened out by weighted gene co-expression network analysis (WGCNA), including SKP1B, BIP5, KCS11, ADH3, BGLU6, and TIFY10B. The results indicated that the defect in starch and sucrose metabolism was the most important factor causing male sterility in NWMS1. Based on the experimental data, a primary molecular regulation model of abnormal anther and pollen developments in mutant NWMS1 was established. These results laid a solid foundation for further research on the molecular mechanism of wheat male sterility.

Highlights

Wheat (Triticum aestivum L.) is one of the most important food crops in the world
Several studies have demonstrated that male sterility occurs at different developmental stages, and the causative factors are various
Ultramicroscopic observation revealed that the tapetum structure of NWMS1 was still complete at the pollen grain mature stage (Figure 2j). These results demonstrate that the pollen abortion of NWMS1 occurred after meiosis and microspore formation

Summary

Introduction

Wheat (Triticum aestivum L.) is one of the most important food crops in the world. With rapid growth of the global population and reduction in cultivated land area, increasing wheat production has become the need of the hour. Wheat productivity will arguably have more influence on global food security than any other crop [1,2,3,4]. Male (anther) development is pivotal for pollen fertility and crop production. Improving the understanding of pollen development may help increase grain yields and facilitate crop breeding [5]. Abnormal anther development may result in male sterility. Stable hereditary male sterility mutants are valuable germplasm resources for heterosis utilization, which is one of the key ways to improve wheat yield [6]. Male sterility permits the production of hybrids on a commercial scale, relying on heterosis in crops, and can greatly increase selection efficiency of the yield [7]. In-depth understanding of the molecular mechanism of male sterility can help us to use it more effectively

Methods

Findings

Discussion

Conclusion