Comparative Transcriptome Analysis of the Anthers from the Cytoplasmic Male-Sterile Pepper Line HZ1A and Its Maintainer Line HZ1B

Zhixing Nie,Weimin Zhu,Jianying Chen,Hong Wang,Qingliang Niu,Hongfei Fu,Yunpeng Song

doi:10.3390/horticulturae7120580

Abstract

Cytoplasmic male-sterility (CMS) is important for the utilization of crop heterosis and study of the molecular mechanisms involved in CMS could improve breeding programs. In the present study, anthers of the pepper CMS line HZ1A and its maintainer line HZ1B were collected from stages S1, S2, and S3 for transcriptome sequencing. A total of 47.95 million clean reads were obtained, and the reads were assembled into 31,603 unigenes. We obtained 42 (27 up-regulated and 15 down-regulated), 691 (346 up-regulated and 345 down-regulated), and 709 (281 up-regulated and 428 down-regulated) differentially expressed genes (DEGs) in stages S1, S2, and S3, respectively. Through Gene Ontology (GO) analysis, the DEGs were found to be composed of 46 functional groups. Two GO terms involved in photosynthesis, photosynthesis (GO:0015986) and photosystem I (GO:0009522), may be related to CMS. Through Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, oxidative phosphorylation (ko00190) and phenylpropanoid biosynthesis (ko00940) were significantly enriched in the S1 and S2 stages, respectively. Through the analysis of 104 lipid metabolism-related DEGs, four significantly enriched KEGG pathways may help to regulate male sterility during anther development. The mitochondrial genes orf470 and atp6 were identified as candidate genes of male sterility for the CMS line HZ1A. Overall, the results will provide insights into the molecular mechanisms of pepper CMS.

Highlights

Pepper (Capsicum annuum L.) is an important global vegetable crop, and most of the varieties grown are hybrids [1]
HZ1A had the typical features of maleMale-fertility phenotypes of the Cytoplasmic male-sterility (CMS) line HZ1A and its maintainer line HZ1B were sterility, including no pollen dissemination around its anthers
A comparative transcriptome analysis of the anthers was conducted between the CMS line HZ1A and its maintainer line HZ1B during three developmental stages

Summary

Introduction

Pepper (Capsicum annuum L.) is an important global vegetable crop, and most of the varieties grown are hybrids [1]. The three-line hybrid breeding system (cytoplasmic male sterility (CMS) line, maintainer line, and restorer line) is critical and widely used for the efficient production of pepper hybrids. In this system, CMS plants must be maintained and restored for seed production. CMS is a common phenomenon that is observed in a diverse array of plant species, such as rice, maize, cotton, and soybean [4,5,6]. It occurs via interactions between the mitochondrial and nuclear genes. There are two types of genes associated with CMS: the restorer of male

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Discussion

Conclusion