A Conserved Regulation of Oil Biosynthesis in Avocado, a Basal Angiosperm
Avocado is an economically important crop with ~ 60-70 % oil, by dry weight, in its fruit mesocarp tissue. The steady increase in global demand for avocado (9% per year) has driven interest to identify the biochemical and molecular factors that regulate its triacylglycerol (TAG, oil) biosynthesis. Using 454- and Illumina-based RNA-Seq approaches, we examined the transcriptional basis for TAG biosynthesis in developing mesocarp of avocado, in relation to other seed and non-seed tissues. Deep transcriptional profiling data allowed us to identify several transcripts that were differentially represented between the early and late developmental stages of mesocarp. Additionally, in all oil-rich tissues analyzed, irrespective of the species, an increased expression was noted for genes mostly associated with fatty acid biosynthesis in plastid, but much less increase in those for TAG assembly in the endoplasmic reticulum. Transcripts associated with hexose metabolism in plastid also showed higher expression, relative to cytosol; this is likely associated with the need for high pyruvate flux directed toward plastid fatty acid synthesis. Moreover, WRINKLED1 transcription factor, a regulatory element associated with oil biosynthesis in seed and non-seed tissues of monocot and dicot plants, was identified in avocado as well. Our studies point to distinctive modes of regulation of fatty acid biosynthesis and TAG assembly that are conserved in both seed and non-seed oil-rich plants. In addition to improving avocado oil production, our study will lead to understanding regulation of oil biosynthesis in coordination with fruit development and identification of ways to generate oil-rich bioenergy crops; a direct implication for the science & society. This study provides an evolutionary insight into conserved nature of oil biosynthesis in a basal angiosperm (avocado) in relation to a monocot (oil palm) and a dicot (brassica). This research will lead to publications for students, sustain existing collaborations (Israel, CA, FL avocado researchers) and generate external funds.
Kilaru, Aruna; Cao, Xia; Sung, Ha-Jung; Mockaitis, Keithanne; and Ohlrogge, John B.. (false). 2013. A Conserved Regulation of Oil Biosynthesis in Avocado, a Basal Angiosperm. American Society for Plant Biology Annual Meeting, Providence, RI. http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=2F614894799DABB8FA4927A30E4963DE?doi=10.1.1.673.5767&rep=rep1&type=pdf