Overexpression of Avocado (Persea americana Mill.) PaRAP2.1 Promotes Fatty Acid Accumulation in Arabidopsis thaliana

Fatty acids in avocado fruit (Persea americana Mill.) are vital composition affecting flavour and nutritive value. Hence, horticulturalists are interested in illustrating the functions of transcription factors on fatty acid accumulation in avocado fruit. In the present study, the APETALA2/ethylene-responsive transcription factor gene, PaRAP2.1, was cloned from avocado mesocarp, and the subcellular localization demonstrated that PaRAP2.1 was located in the cytoplasm and nucleus. The PaRAP2.1 was introduced into Arabidopsis thaliana by Agrobacterium-mediated transformation. Furthermore, PaRAP2.1 were functionally verified its effect on fatty acid biosynthesis. Histological analyses of lipid droplets displayed that the striking difference in the lipid droplets in the mature seeds between PaRAP2.1-overexpressing transgenic and wild-type Arabidopsis thaliana lines were revealed based on confocal microscopy images. Subsequently, fatty acid analyses of PaRAP2.1-overexpressing Arabidopsis thaliana lines displayed the significantly higher contents of fatty acids than those in the wild-type plants. Meanwhile, expression amount of ten genes involving in fatty acid biosynthesis dramatically up-regulated in the mature seeds of PaRAP2.1-overexpressing lines than those of wild-type plants. These results provide a theoretical basis for future research in regard to the function of PaRAP2.1 on fatty acid biosynthesis.