Abstract Detail

Developmental and Structural Section

Khan, Deirdre [1], Millar, Jenna [1], Girard, Ian J. [1], Chan, Ainsley [1], Becker, Michael [1], Belmonte, Mark [1].

Transcriptome atlas of the Arabidopsis funiculus – a study of maternal seed regions.

The funiculus is the structure that connects the developing seed to the maternal plant, and is the only direct conduit for the transport of nutrients from the plant to the seed. Understanding the molecular genetics of funiculus development could contribute greatly to oilseed improvement research, but the accessibility of this structure and the analysis of large-scale datasets remains a challenge in the growing field of transcriptomics. We therefore studied the funiculus of the model plant, Arabidopsis thaliana, in order to provide insight into the biological processes and regulatory molecules that control these processes in space and time.
Using laser micro-dissection coupled with global mRNA profiling experiments of the seed transcriptome throughout development, we compared the funiculus with all subregions of the maternal (funiculus, seed coat) and zygotic (embryo, suspensor, endosperm) regions of the Arabidopsis seed. Using fuzzy-K means clustering, we generated dominant patterns of gene activity and performed Gene Ontology term enrichment analysis to uncover biological processes in the funiculus and other seed regions. These data are supported by our histological and anatomical analyses of the funiculus. Enrichment of sequence motifs, transcriptional regulators, and GO terms in funiculus mRNA populations was used to predict putative regulatory networks underlying funiculus development and function throughout seed development. Our data show that the funiculus is a transcriptomically distinct region of the seed. Our data indicate that the funiculus is an energetically active region that is enriched for fatty acid metabolism, auxin response, and vascular development. The funiculus was also found to be enriched for glucosinolate biosynthesis, and many transcripts involved in glucosinolate biosynthesis and regulation were found to accumulate almost exclusively in the funiculus. Our analysis predicts MYC4 and AT4G00870 as regulators of glucosinolate biosynthesis and auxin response in the funiculus via interaction with the MYC2 binding motif. We also identify BEE2 and AT1G22490 as potential regulators of auxin response in the funiculus. We also identified several other transcripts that are specific to the funiculus in seed development, and unique to the funiculus in plant development overall.
Our study provides the first comprehensive analysis of funiculus development, setting a new foundation in the field of seed improvement research in Arabidopsis that can be extended to other members of the Brassicaceae. Understanding regulators of funiculus development and function in Arabidopsis may have great implications for our ability to enhance seed development via the manipulation of maternal tissues.

1 - University of Manitoba, Biological Sciences, Winnipeg, MB, R3T 2N2, Canada

Keywords:
Arabidopsis
seed coat
laser microdissection
Transcriptome
seed
funiculus.

Presentation Type: Oral Paper:Papers for Sections
Session: 45
Location: Salon 11/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 3:00 PM
Number: 45007
Abstract ID:211
Candidate for Awards:Katherine Esau Award,Cinq Mars Award,CSPB President's Award for Best Student Presentation,CSPB Travel Bursary