Defective pollen wall contributes to male sterility in the male sterile line 1355A of cotton.

Yuanlong Wu,Daojun Yuan,Li Yang,Xiyan Yang,Xiaoping Guo,Zancheng Wu,Xianlong Zhang,Longfu Zhu,Ling Min

doi:10.1038/srep09608

Abstract

To understand the mechanisms of male sterility in cotton (Gossypium spp.), combined histological, biochemical and transcription analysis using RNA-Seq was carried out in the anther of the single-gene recessive genic male sterility system of male sterile line 1355A and male fertile line 1355B, which are near-isogenic lines (NILs) differing only in the fertility trait. A total of 2,446 differentially expressed genes were identified between the anthers of 1355AB lines, at three different stages of development. Cluster analysis and functional assignment of differentially expressed genes revealed differences in transcription associated with pollen wall and anther development, including the metabolism of fatty acids, glucose, pectin and cellulose. Histological and biochemical analysis revealed that a major cellular defect in the 1355A was a thicker nexine, consistent with the RNA-seq data, and further gene expression studies implicated differences in fatty acids synthesis and metabolism. This study provides insight into the phenotypic characteristics and gene regulatory network of the genic male sterile line 1355A in upland cotton.

Highlights

Fourteen stages of anther development were identified based on the distinctive cellular events of Arabidopsis thaliana and G. hirsutum (Coker 315) anther development stages[29,30] (Supplementary Table S1 and Supplementary Fig. S1)
Through comparing the definition of anther development stages in Arabidopsis thaliana and G. hirsutum of Coker 315 line and 1355B line (Supplementary Table S1), we conclude that cotton anther development is similar to that of Arabidopsis thaliana
One important difference between anther development in cotton and Arabidopsis thaliana is that the tapetal cell degradation commences earlier in cotton than in Arabidopsis thaliana (Supplementary Table S1), the other is the structure of the pollen wall

Summary

Introduction

A total of 2,446 differentially expressed genes were identified between the anthers of 1355AB lines, at three different stages of development. Cluster analysis and functional assignment of differentially expressed genes revealed differences in transcription associated with pollen wall and anther development, including the metabolism of fatty acids, glucose, pectin and cellulose. Histological and biochemical analysis revealed that a major cellular defect in the 1355A was a thicker nexine, consistent with the RNA-seq data, and further gene expression studies implicated differences in fatty acids synthesis and metabolism. In the 1355A male sterile plant, the exine spine is not produced at the uninucleate stage, and the thickness of the pollen wall increases[2]. When www.nature.com/scientificreports the tapetum degrades, the remnants deposit as tryphine to fill the exine cavities, and the mature pollen wall is formed

Methods

Results

Conclusion