[P4] Crop Genetics and Physiology

[P4-12] DGAT1s from Different Plant Species Show Different Triacylglycerol Biosynthesis Activities

^○Tomoko Hatanaka¹, Wakana Miyashita¹, Kouki Shibutani², Daisuke Matsuoka¹, Daisuke Sasayama¹, Hiroshi Fukayama¹, Tetsushi Azuma¹, David F. Hildebrand³ (1.Graduate School of Agricultural Science, Kobe University, Japan, 2.Faculty of Agriculture, Kobe University, Japan, 3.Department of Plant and Soil Sciences, University of Kentucky, United States)

Triacylglycerols (TAGs) are the major component of plant storage lipids. Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final step of Kennedy pathway and it is considered a rate-limiting enzyme responsible for plant oil accumulation. In our former study, the DGAT1 cDNAs obtained from Arabidopsis (Arabidopsis thiliana), soybean (Glycine max), castor bean (Ricinus communis), and Vernonia (Vernonia galamensis) were introduced into Arabidopsis. All Vernonia DGAT1 expressing lines showed a significantly higher seed oil content compared to the wild type followed by soybeanDGAT1, castor bean DGAT1 and Arabidopsis DGAT1. These results reflected our previous results from the yeast microsome assay (Hatanaka et al. 2016).
In this study, in addition to the above four DGAT1s, cDNAs of DGAT1 were cloned from sunflower (Helianthus annuus), Jatropha (Jatropha curcas) and sesame (Sesamum indicum). The sunflower DGAT1 has one of the closest amino acid sequence to Vernonia DGAT1. In regards to Jatropha and sesame DGAT1s, it has been reported that they were effective to increase seed oil contents of Arabidopsis (Misra et al. 2013, Wang et al. 2014). These DGAT1 genes from seven species were introduced into the TAG biosynthesis defective yeast mutant (H1246). In the yeast expression culture, DGAT1s from Arabidopsis, castor bean or soybean did not increase TAG content in the yeast significantly, however, DGAT1s from Vernonia, sunflower, Jatropha and sesame remarkably increased TAG content more than 10 times higher than the former three DGAT1s.