Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Millar, Jenna [1], Becker, Michael [1], Chan, Ainsley [1], Belmonte, Mark [2].

Tissue-specific RNA sequencing and laser microdissection of the Brassica napus (canola) maternal seed subregions.

Canola contributes $19.3 billion to the Canadian economy each year due to its highly nutritive oil and protein reserves within the embryo. Embryo development and nutrient accumulation require the coordinated development and communication between all seed regions and subregions. The maternal tissues of the seed can be divided into a number of subregions including the outer and inner integuments surrounding the seed, the chalazal proliferating tissue (CPT) that subtends the chalazal endosperm, and the chalazal seed coat (CZSC) that serves as the first connection between the funiculus and the seed. While much research has been carried out on the filial embryo and endosperm, we have yet to fully understand the genes required to program the development of the maternal subregions at the cellular level in canola. Our research couples histological techniques with next-generation RNA sequencing to profile the genes and elucidate gene regulatory networks responsible for the development of the uncharacterized maternal seed subregions. The anatomy of the maternal subregions was studied using light and transmission electron microscopy across seed development. We then profiled each of the maternal subregions using laser microdissection coupled with next-generation RNA sequencing technology. These combined methods provide a high-resolution dataset of the transcriptional networks operative within the maternal seed. Vigorous bioinformatics analyses, including hierarchical and fuzzy-K means clustering analyses combined with GO term enrichment, were then used to predict and compare biological function and cellular processes across the maternal subregions in both space and time. Fuzzy-K means clustering analysis identified dominant patterns of gene activity between the different maternal subregions of the canola seed. Subsequent GO term enrichment showed that the CZSC has mRNAs associated with transport processes and also identified putative regulators of these processes operative in the CZSC and other maternal seed subregions. Supporting this, light and electron microscopy identified vascular tissue of the funiculus, which supplies the seed with nutrients, terminating in the CZSC suggesting the CZSC is an unloading zone. In addition, plasmodesmata were identified between the cells of the CZSC, suggesting symplastic transport is likely present within this subregion. Our combined anatomical and global transcriptomic datasets provides strong evidence that the maternal seed subregions in canola possess not only a structural and protective function but also serves a putative role in the transport of materials to the filial embryo and endosperm. Our data further provide a substantial informatics resource for those interested in oilseed genomics for improved seed development.

1 - University of Manitoba, Biological Sciences, 50 Sifton Road, Winnipeg, MB, R3T2N2, Canada
2 - University of Manitoba, Biological Sciences, 50 Sifton Road, Winnipeg, MB, R3T 2N2, Canada

Keywords:
laser microdissection
RNA Sequencing
Brassica napus
Transcriptome
seed coat
seed.

Presentation Type: Oral Paper:Papers for Topics
Session: 26
Location: Hall B/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:45 AM
Number: 26004
Abstract ID:213
Candidate for Awards:Katherine Esau Award,Cinq Mars Award,CSPB President's Award for Best Student Presentation,CSPB Travel Bursary