title: Ectopic expression ofAtDGAT1, encoding diacylglycerolO-acyltransferase exclusively committed to TAG biosynthesis, enhances oil accumulation in seeds and leaves of Jatropha.
abstract: BACKGROUND
  Jatropha curcasis an important biofuel crop due to the presence of high amount of oil in its seeds suitable for biodiesel production. Triacylglycerols (TAGs) are the most abundant form of storage oil in plants. DiacylglycerolO-acyltransferase (DGAT1) enzyme is responsible for the last and only committed step in seed TAG biosynthesis. Direct upregulation of TAG biosynthesis in seeds and vegetative tissues through overexpression of theDGAT1could enhance the energy density of the biomass, making significant impact on biofuel production.
  
  
  RESULTS
  The enzyme diacylglycerolO-acyltransferase is the rate-limiting enzyme responsible for the TAG biosynthesis in seeds. We generated transgenic Jatropha ectopically expressing anArabidopsis DGAT1gene throughAgrobacterium-mediated transformation. The resultingAtDGAT1transgenic plants showed a dramatic increase in lipid content by 1.5- to 2 fold in leaves and 20-30 % in seeds, and an overall increase in TAG and DAG, and lower free fatty acid (FFA) levels compared to the wild-type plants. The increase in oil content in transgenic plants is accompanied with increase in average plant height, seeds per tree, average 100-seed weight, and seed length and breadth. The enhanced TAG accumulation in transgenic plants had no penalty on the growth rates, growth patterns, leaf number, and leaf size of plants.
  
  
  CONCLUSIONS
  In this study, we produced transgenic Jatropha ectopically expressingAtDGAT1. We successfully increased the oil content by 20-30 % in seeds and 1.5- to 2.0-fold in leaves of Jatropha through genetic engineering. Transgenic plants had reduced FFA content compared with control plants. Our strategy of increasing energy density by enhancing oil accumulation in both seeds and leaves in Jatropha would make it economically more sustainable for biofuel production.
authors: Center for Energy, Indian Institute of Technology Guwahati, Guwahati, 781039 India.
authors: Devendra Kumar
authors: DK
authors: Maravi
authors: Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039 India.
authors: Sanjeev
authors: S
authors: Kumar
authors: Center for Energy, Indian Institute of Technology Guwahati, Guwahati, 781039 India.
authors: Prabin Kumar
authors: PK
authors: Sharma
authors: Center for Energy, Indian Institute of Technology Guwahati, Guwahati, 781039 India ; Applied Biological Sciences, Gifu University, 1-1, Yanagido, Gifu, 501-1193 Japan.
authors: Yasufumi
authors: Y
authors: Kobayashi
authors: Center for Energy, Indian Institute of Technology Guwahati, Guwahati, 781039 India ; Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039 India.
authors: Vaibhav V
authors: VV
authors: Goud
authors: Department of Technology Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818 Japan.
authors: Nozomu
authors: N
authors: Sakurai
authors: Applied Biological Sciences, Gifu University, 1-1, Yanagido, Gifu, 501-1193 Japan.
authors: Hiroyuki
authors: H
authors: Koyama
authors: Center for Energy, Indian Institute of Technology Guwahati, Guwahati, 781039 India ; Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039 India.
authors: Lingaraj
authors: L
authors: Sahoo
keywords: AtDGAT1; Biodiesel; Jatropha; Leaf; Seed oil; Transgenic; Triacylglycerols (TAGs)