College of Agronomy and Biotechnology, Chongqing Engineering Research Center for Rapeseed, Academy of Agricultural Sciences, Southwest University, Chongqing, 400716, China.
Mol Genet Genomics. 2018 Dec;293(6):1421-1435. doi: 10.1007/s00438-018-1468-8. Epub 2018 Jul 4.
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.
种子老化是油料作物种质资源保存中不可避免的问题。因此，阐明种子老化的遗传机制对于油菜育种至关重要。本研究将甘蓝型油菜种子置于人工老化环境（40°C 和 90%相对湿度）中。利用 172 个重组自交系群体，在 8 条染色体上检测到 13 个 QTL，这些 QTL 解释了约 9.05%的总表型变异。在两个环境中鉴定到的 QTL q2015AGIA-C08 和 q2016AGI-C08-2 被认为是同一个 QTL。人工老化后，发芽指数降低，相对电导率、丙二醛和脯氨酸含量增加，可溶性糖、蛋白质含量和抗氧化酶活性降低。此外，对未经处理（R0 和 S0）或经过 15 天人工老化（R15 和 S15）的极端系种子进行转录组测序。总共在 R15 与 R0、S15 与 S0、R0 与 S0 和 R15 与 S15 之间分别鉴定到 2843、1084、429 和 1055 个差异表达基因。通过整合 QTL 作图和 RNA-seq 分析，筛选到 7 个候选基因，如编码热休克转录因子 C1 的 BnaA03g37460D 和编码磷酸果糖激酶 4 的 BnaA03g40360D。进一步研究这些候选基因可以加深我们对种子老化调控机制的理解。
