Abstract - Metabolic engineered tobacco plants accumulating oil in vegetative tissues have been developed to meet future plant oil demands. These transgenic plants can produce up to 30% oil in controlled environments. However, their performance in field-like conditions subjected to potential stresses is unknown. Here, wild type (WT) tobacco and high leaf oil (HLO) transgenic plants were exposed to moderate, sustained water stress to mimic field conditions. The effect of water stress on biomass and triacylglycerol (TAG) accumulation was investigated at the physiological, biochemical, and transcriptional levels. The results demonstrated that water stress caused a lower biomass penalty in HLO than in WT. Water stress enhanced TAG accumulation, but a transcriptomic analysis indicated that this occurred by different mechanisms in the WT and HLO plants. In WT, water stress upregulated genes encoding Phosphatidic acid phosphatase (PAP), diacylglycerol O-acyltransferase (DGAT), and lipid droplet-associated proteins (LDAP) and downregulated genes encoding GDSL lipases. By contrast, the enhancement of TAG accumulation in HLO in the same condition was achieved mainly through the upregulating Oleosin and downregulation of GDSL lipases. This study demonstrated the feasibility of TAG production in HLO leaves under water stress.

Biography - Dr Jing Zhang is a Postdoctoral Fellow at CSIRO Agriculture and Food, investigating the effects of abiotic stresses on oil accumulation and improving biomass of high leaf oil tobacco plants. She received her PhD degree at Huazhong Agricultural University and studied at the University of Western Australia as a joint PhD student for two years. Her PhD research focused on physiological responses to drought stress and identifying drought-related genes in canola. Subsequently, she worked at HZAU for two years as a postdoctoral researcher exploring the drought tolerance mechanism in canola based on genome-wide association analysis.