title: High light exposure on seed coat increases lipid accumulation in seeds of castor bean (Ricinus communis L.), a nongreen oilseed crop.
abstract: Little was known on how sunlight affects the seed metabolism in nongreen seeds. Castor bean (Ricinus communis L.) is a typical nongreen oilseed crop and its seed oil is an important feedstock in industry. In this study, photosynthetic activity of seed coat tissues of castor bean in natural conditions was evaluated in comparison to shaded conditions. Our results indicate that exposure to high light enhances photosynthetic activity in seed coats and consequently increases oil accumulation. Consistent results were also reached using cultured seeds. High-throughput RNA-Seq analyses further revealed that genes involved in photosynthesis and carbon conversion in both the Calvin-Benson cycle and malate transport were differentially expressed between seeds cultured under light and dark conditions, implying several venues potentially contributing to light-enhanced lipid accumulation such as increased reducing power and CO2 refixation which underlie the overall lipid biosynthesis. This study demonstrated the effects of light exposure on oil accumulation in nongreen oilseeds and greatly expands our understanding of the physiological roles that light may play during seed development in nongreen oilseeds. Essentially, our studies suggest that potential exists to enhance castor oil yield through increasing exposure of the inflorescences to sunlight either by genetically changing the plant architecture (smart canopy) or its growing environment.
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 88 Xuefu Road, Kunming, 650223, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Indian Institute of Oilseeds Research, Rajendranagar, Hyderabad, 500 030, India.
authors.forename: Sujatha
authors.initials: S
authors.lastname: Mulpuri
authors.affiliation: Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650204, China. aizhongl@yahoo.com.
authors.forename: Aizhong
authors.initials: A
authors.lastname: Liu
mesh_terms: D053898:Biosynthetic Pathways; D057486:Carbon Cycle / Q000528:radiation effects; D002368:Castor Oil / Q000378:metabolism / Q000528:radiation effects*; D002734:Chlorophyll / Q000378:metabolism; D003624:Darkness; D005453:Fluorescence; D059014:High-Throughput Nucleotide Sequencing; D056626:Inflorescence / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D050356:Lipid Metabolism; D010788:Photosynthesis / Q000528:radiation effects*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012278:Ricinus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D013472:Sunlight; D059467:Transcriptome
chemical_list: D010940:Plant Proteins; D002734:Chlorophyll; D002368:Castor Oil
keywords: Castor bean; Light exposure; Nongreen oilseed; Oil accumulation; Seed coat