Combined QTL mapping, physiological and transcriptomic analyses to identify candidate genes involved in Brassica napus seed aging
Seed aging is an inevitable problem in the germplasm conservation of oil crops. Thus, clarifying the genetic mechanism of seed aging is important for rapeseed breeding. In this study, Brassica napus seeds were exposed to an artificial aging environment (40 °C and 90% relative humidity). Using a population of 172 recombinant inbred lines, 13 QTLs were detected on 8 chromosomes, which explained ~ 9.05% of the total phenotypic variation. The QTLs q2015AGIA-C08 and q2016AGI-C08-2 identified in the two environments were considered the same QTL. After artificial aging, lower germination index, increased relative electrical conductivity, malondialdehyde and proline content, and reduced soluble sugar, protein content and antioxidant enzyme activities were detected. Furthermore, seeds of extreme lines that were either left untreated (R0 and S0) or subjected to 15 days of artificial aging (R15 and S15) were used for transcriptome sequencing. In total, 2843, 1084, 429 and 1055 differentially expressed genes were identified in R15 vs. R0, S15 vs. S0, R0 vs. S0 and R15 vs. S15, respectively. Through integrated QTL mapping and RNA-sequencing analyses, seven genes, such as BnaA03g37460D, encoding heat shock transcription factor C1, and BnaA03g40360D, encoding phosphofructokinase 4, were screened as candidate genes involved in seed aging. Further researches on these candidate genes could broaden our understanding of the regulatory mechanisms of seed aging.
KeywordsBrassica napus Seed artificial aging Physiology QTL analysis Transcriptome
Quantitative trait locus
Recombinant inbred lines
Differentially expressed genes
Heat shock proteins
Protein l-isoaspartyl methyltransferase
- LEA protein
Late embryogenesis abundant protein
Bovine serum albumin
High-performance liquid chromatography–mass spectrometry
RNA integrity number
Fragments per kilobase million
Kyoto Encyclopedia of Genes and Genomes
This work was supported by the National Natural Science Foundation of China (31371655, 31771830), the Fundamental Research Funds for Central Universities (XDJK2017A009 and XDJK2017D076), and the Chongqing Science and Technology Commission (cstc2016shmszx80083).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
This article does not contain any studies with human participants or animals performed by any of the authors.
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