Articles
The genes associated with citrus male sterility explored using GBS-GWAS combined with transcriptome sequencing of bulk segregant population
Article number
1448_30
Pages
237 – 250
Language
English
Abstract
Male sterility is an important trait in citrus breeding due to its value in producing seedless fruits.
Male sterility can often be easily recognized based on anther color and pollen grain number per anther.
Genic male sterility (GMS) in citrus is caused by nuclear gene mutations.
Identifying genes related to this trait will provide insight into the mechanism of pollen development and facilitate the breeding of seedless cultivars.
In this study, the anther color was used as a phenotypic marker to evaluate male sterility in 240 citrus germplasm accessions.
Additionally, genotyping by sequencing (GBS) was employed to obtain genotype data.
The GWAS analysis was performed to identify candidate SNPs loci related to male sterility.
The candidate genes were annotated and further verified by transcriptome sequencing with two bulk segregant populations designed as male fertile population (MFP) and male sterile population (MSP), which comprised anthers from six male-fertile and six male-sterile accessions, respectively.
The genomic sequences of the candidate gene PEG and its flanking region from male-fertile and -sterile accessions were compared to reveal variations that might contribute to male sterility.
Consequently, GWAS analysis identified ten SNPs significantly associated with male sterility, of which the most significant two SNPs corresponded to pectinesterase gene (PEG). Transcriptome sequencing of two bulk populations showed that PEG and its flanking S1-ribonuclease gene (RN) were expressed more abundantly in MFP than in MSP. Through BLAST search and genome comparison of ‘Clementine’ mandarin (Citrus clementina hort. ex.
Tanaka) and satsuma (Citrus unshiu Macf.), a long-terminal repeat retrotransposon (LTR-RT) was found inserted into the 5’ and 3’ UTR of PEG, and several insertion/deletion mutations were present in PEG and RN, which are located within the LTR-RT. qRT-PCR validated the differential expression levels of PEG, RN and serine/threonine-protein kinase PBS1 between male fertile and male sterile cultivars.
Furthermore, based on the RN sequence, PCR primers were developed to discriminate citrus male sterile accessions.
This study provides insight into the mechanism of genic male sterility in citrus, and the developed molecular markers could be applied in citrus seedless breeding programs.
Male sterility can often be easily recognized based on anther color and pollen grain number per anther.
Genic male sterility (GMS) in citrus is caused by nuclear gene mutations.
Identifying genes related to this trait will provide insight into the mechanism of pollen development and facilitate the breeding of seedless cultivars.
In this study, the anther color was used as a phenotypic marker to evaluate male sterility in 240 citrus germplasm accessions.
Additionally, genotyping by sequencing (GBS) was employed to obtain genotype data.
The GWAS analysis was performed to identify candidate SNPs loci related to male sterility.
The candidate genes were annotated and further verified by transcriptome sequencing with two bulk segregant populations designed as male fertile population (MFP) and male sterile population (MSP), which comprised anthers from six male-fertile and six male-sterile accessions, respectively.
The genomic sequences of the candidate gene PEG and its flanking region from male-fertile and -sterile accessions were compared to reveal variations that might contribute to male sterility.
Consequently, GWAS analysis identified ten SNPs significantly associated with male sterility, of which the most significant two SNPs corresponded to pectinesterase gene (PEG). Transcriptome sequencing of two bulk populations showed that PEG and its flanking S1-ribonuclease gene (RN) were expressed more abundantly in MFP than in MSP. Through BLAST search and genome comparison of ‘Clementine’ mandarin (Citrus clementina hort. ex.
Tanaka) and satsuma (Citrus unshiu Macf.), a long-terminal repeat retrotransposon (LTR-RT) was found inserted into the 5’ and 3’ UTR of PEG, and several insertion/deletion mutations were present in PEG and RN, which are located within the LTR-RT. qRT-PCR validated the differential expression levels of PEG, RN and serine/threonine-protein kinase PBS1 between male fertile and male sterile cultivars.
Furthermore, based on the RN sequence, PCR primers were developed to discriminate citrus male sterile accessions.
This study provides insight into the mechanism of genic male sterility in citrus, and the developed molecular markers could be applied in citrus seedless breeding programs.
Publication
Authors
D. Jiang, H.L. Yue, X. Yu, W.F. Yao, Z. Zhang, H.J. Gao, X.K. Wang
Keywords
male sterility, citrus, GBS, bulk segregant population, transcriptome sequencing
Groups involved
Online Articles (103)