Comparative transcriptomics and proanthocyanidin metabolism in pea (Pisum sativum) seed coat
Abstract
Plants produce a vast array of specialized compounds known as secondary metabolites, which were originally thought to be non-essential for plant survival. However, we now know that secondary metabolites play integral roles in plant defense, signalling, reproduction and more. Proanthocyanidins (PAs) are a class of flavonoid polymers derived from the phenylpropanoid pathway. PAs accumulate in the seed coat, bark, and leaves of many plants and are believed to play a role in plant defense. Recent evidence of health benefits associated with PA consumption has spurred new research interests in PA biosynthesis. Many of the studies of seed coat PA biosynthesis have been conducted in non-crop species that produce a limited variety of PAs. Pea (Pisum sativum) offers a number of unique advantages for PA research. Peas produce large seed coats, which are easy to isolate. Dry peas are an important source of nutrition for both humans and livestock, enabling research integration into the human diet and commercial agriculture. Finally, centuries of breeding have produced a wide variety of pea cultivars, making pea a valuable phenotypic and genetic resource for plant research. Despite these advantages, PA biosynthesis in pea has not been well characterized. This work presents the seed coat PA chemical profile of three pea cultivars and the biochemical characterization of two PA branch point enzymes, anthocyanidin reductase and leucoanthocyanidin reductase, from pea. In addition, the seed coat transcriptomes of these three varieties were compared to those of two varieties lacking PAs in an effort to elucidate novel genetic mechanisms relating to PA biosynthesis. This comparative transcriptomic analysis was expanded to study general seed phenotypic differences between pea cultivars. Two target genes were identified; one related to seed weight and another to PAs, the latter of which was further characterized.
Description
Keywords
Bioinformatics, Biology--Molecular, Biochemistry
Citation
Ferraro, K. (2014). Comparative transcriptomics and proanthocyanidin metabolism in pea (Pisum sativum) seed coat (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25368