Correlation of Kennedy pathway efficiency with seed oil content of canola (Brassica napus L.) lines

Abstract

The Kennedy pathway (KP) has been demonstrated to be crucial for seed oil accumulation. To answer whether the KP enzyme activities can explain seed oil content variation of conventional canola lines, six lines with three different levels of oil (high, middle and low) were tested for seed KP enzyme activities and hexose (2 sucrose+glucose+fructose) concentrations at 18, 25, 32, 39 and 46 d after pollination (DAP). The results showed that lines with high and middle seed oil content levels (HO and MO) had higher phosphatidate phosphatase (PAP) and diacylglycerol acyltransferase (DGAT) activities and higher sugar contents than the lines with low oil levels (LO). The lowest KP enzyme activity (LEA) for each combination of line and DAP can be regarded as indicator to the bioassembly efficiency. In most of the combinations, DGATwas the enzyme with LEA, and glycerol-3- phosphate acyltransferase (GPAT) or PAP acted as the enzyme with LEA in a few cases. Correlation analyses showed that peak values and averages of LEA in the lines were significantly correlated with seed oil content, indicating that KP enzyme efficiency is tightly associated with seed oil content.