title: Maternal control of seed oil content in Brassica napus: the role of silique wall photosynthesis.
abstract: Seed oil content is an important agronomic trait in rapeseed. However, our understanding of the regulatory processes controlling oil accumulation is still limited. Using two rapeseed lines (zy036 and 51070) with contrasting oil content, we found that maternal genotype greatly affects seed oil content. Genetic and physiological evidence indicated that difference in the local and tissue-specific photosynthetic activity in the silique wall (a maternal tissue) was responsible for the different seed oil contents. This effect was mimicked by in planta manipulation of silique wall photosynthesis. Furthermore, the starch content and expression of the important lipid synthesis regulatory gene WRINKLED1 in developing seeds were linked with silique wall photosynthetic activity. 454 pyrosequencing was performed to explore the possible molecular mechanism for the difference in silique wall photosynthesis between zy036 and 51070. Interestingly, the results suggested that photosynthesis-related genes were over-represented in both total silique wall expressed genes and genes that were differentially expressed between genotypes. A potential regulatory mechanism for elevated photosynthesis in the zy036 silique wall is proposed on the basis of knowledge from Arabidopsis. Differentially expressed ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco)-related genes were used for further investigations. Oil content correlated closely with BnRBCS1A expression levels and Rubisco activities in the silique wall, but not in the leaf. Taken together, our results highlight an important role of silique wall photosynthesis in the regulation of seed oil content in terms of maternal effects.
authors.affiliation: Key Laboratory of Oil Crop Biology of the Ministry of Agriculture, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Hua
authors.forename: Rong-Jun
authors.initials: RJ
authors.lastname: Li
authors.forename: Gao-Miao
authors.initials: GM
authors.lastname: Zhan
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Xin-Fa
authors.initials: XF
authors.lastname: Wang
authors.forename: Gui-Hua
authors.initials: GH
authors.lastname: Liu
authors.forename: Han-Zhong
authors.initials: HZ
authors.lastname: Wang
mesh_terms: D029688:Brassica napus / Q000235:genetics* / Q000502:physiology; D020224:Expressed Sequence Tags; D035264:Flowers / Q000378:metabolism / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D005838:Genotype; D010788:Photosynthesis / Q000502:physiology*; D010938:Plant Oils / Q000737:chemistry*; D018749:RNA, Plant / Q000235:genetics; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D012639:Seeds / Q000737:chemistry*; D017422:Sequence Analysis, DNA; D013213:Starch / Q000096:biosynthesis; D059467:Transcriptome
chemical_list: D010938:Plant Oils; D018749:RNA, Plant; D013213:Starch; D012273:Ribulose-Bisphosphate Carboxylase