Seed and fruit development occur in a coordinated manner following fertilization.  The seed, which is a ‘sink’ tissue, is supplied with nutrients from the mother plant through the vasculature of the fruit tissue. In plants such as avocado and olive where lipid accumulation occurs primarily in the fruit tissue (and < 2% in the seed; the metabolic regulation of resource allocation towards various tissues is not understood.
Figure 1: Evolutionary position of avocado relative to other species of interest is shown (bar = % divergence). The avocado fruit indicates mesocarp (M) and seed (S). The Venn diagram indicates that comparison of the seed and non-seed transcriptomes is expected to reveal seed- and non-seed (mesocarp) specific transcription factors. |
Our hypothesis is that the comparison of transcriptome of fruit and seed will aid in identification of the regulatory systems that control carbon partitioning between these tissues (Figure 1).
Using Next Generation (454 and Illumina) sequencing technique, transcriptional profile for five developing stages of avocado mesocarp was generated. Immediate goals of the project include mining ~150 million EST data to gain insights into gene expression of enzymes leading to oil biosynthesis and transcriptional regulation of carbon partitioning during lipid accumulation in non-seed tissues. Focus will be on identification of non-seed specific transcription factors, involved in lipid biosynthesis, identifying their target genes and validating their function in other dicot and monocot species. These studies, in the long-term will have implications for not only understanding the fundamental aspects of plant lipid biosynthesis but also for developing crops with improved oil and energy content. |
