Identification of Acyltransferases Associated with Triacylglycerol Biosynthesis in Avocado

• Main Author: Sung, Ha-Jung
• Format: Others
• Published: Digital Commons @ East Tennessee State University 2013
• Subjects: avocado; diacylglycerol acyltransferase; lipid biosynthesis; mesocarp; phospholipid:diacylglycerol acyltransferase; triacylglycerol; Biochemistry; Fruit Science; Plant Biology
• Online Access: https://dc.etsu.edu/etd/2311; https://dc.etsu.edu/cgi/viewcontent.cgi?article=3656&context=etd

A variety of plants synthesize and store oil in the form of triacylglycerols (TAG) in their seed and nonseed tissues that are commonly used as vegetable oils. In seed tissues, an acyl CoA-dependent diacylglycerol (DAG) acyltransferase (DGAT) and/or -independent phospholipid:DGAT (PDAT) catalyze the conversion of DAG to TAG. In avocado fruit, which stores up to 70% oil by dry weight in mesocarp, it is hypothesized that both DGAT and PDAT are likely involved in TAG synthesis. To investigate, TAG content and composition and transcript levels for the acyltransferases in avocado fruit were quantified by gas chromatography and real-time polymerase chain reaction, respectively. Temporal, tissue-specific and phenotypic comparisons revealed that while DGAT1 gene expression was specifically associated with TAG accumulation, PDAT also correlated with higher levels of polyunsaturated fatty acid; DGAT2 was barely detectable. These studies suggest that TAG biosynthesis in nonseed tissues of avocado involves acyl CoA-dependent and -independent reactions.