Maternal control of seed oil content in Brassica napus: the role of silique wall photosynthesis

• Published in: The Plant journal : for cell and molecular biology Vol. 69; no. 3; pp. 432 - 444
• Main Authors: Hua, Wei, Li, Rong‐Jun, Zhan, Gao‐Miao, Liu, Jing, Li, Jun, Wang, Xin‐Fa, Liu, Gui‐Hua, Wang, Han‐Zhong
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2012; Blackwell
• Subjects: 454 pyrosequencing; Biological and medical sciences; Brassica napus; Brassica napus - genetics; Brassica napus - physiology; Expressed Sequence Tags; Flowers - metabolism; Flowers - physiology; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant; Gene Library; Genes, Plant; Genotype; Lipids; maternal effects; Metabolism; Photosynthesis; Photosynthesis - physiology; Photosynthesis, respiration. Anabolism, catabolism; Plant biology; Plant Oils - chemistry; Plant physiology and development; Rape plants; Ribulose-Bisphosphate Carboxylase - metabolism; RNA, Plant - genetics; seed oil content; Seeds - chemistry; Sequence Analysis, DNA; silique wall; Starch - biosynthesis; Transcriptome; Seeds; seed oil content; silique wall; Regulation(control); Oil; Cruciferae; Dicotyledones; Seed; maternal effects; Angiospermae; Brassica napus; 454 pyrosequencing; Spermatophyta; Maternal effect; Silique; Photosynthesis
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.2011.04802.x

Summary 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.