title: Dissecting the Genetic Basis for Seed Coat Mucilage Heteroxylan Biosynthesis inPlantago ovataUsing Gamma Irradiation and Infrared Spectroscopy.
abstract: Seeds from the myxospermous speciesPlantago ovatarelease a polysaccharide-rich mucilage upon contact with water. This seed coat derived mucilage is composed predominantly of heteroxylan (HX) and is utilized as a gluten-free dietary fiber supplement to promote human colorectal health. In this study, a gamma-irradiatedP. ovatapopulation was generated and screened using histological stains and Fourier Transform Mid Infrared (FTMIR) spectroscopy to identify putative mutants showing defects in seed coat mucilage HX composition and/or structure. FTMIR analysis of dry seed revealed variation in regions of the IR spectra previously linked to xylan structure inSecale cereale(rye). Subsequent absorbance ratio and PCA multivariate analysis identified 22 putative mutant families with differences in the HX IR fingerprint region. Many of these showed distinct changes in the amount and subtle changes in structure of HX after mucilage extrusion, while 20% of the putative HX mutants identified by FTMIR showed no difference in staining patterns of extruded mucilage compared to wild-type. Transcriptional screening analysis of two putativereduced xylan in mucilage(rxm) mutants,rxm1andrxm3, revealed that changes in HX levels inrxm1correlate with reduced transcription of known and novel genes associated with xylan synthesis, possibly indicative of specific co-regulatory units within the xylan biosynthetic pathway. These results confirm that FTMIR is a suitable method for identifying putative mutants with altered mucilage HX composition inP. ovata, and therefore forms a resource to identify novel genes involved in xylan biosynthesis.
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, University of Adelaide, Waite Campus, Urrbrae, SAAustralia; School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SAAustralia.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Tucker
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, University of Adelaide, Waite Campus, Urrbrae, SAAustralia; School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SAAustralia.
authors.forename: Chao
authors.initials: C
authors.lastname: Ma
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, University of Adelaide, Waite Campus, Urrbrae, SAAustralia; School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SAAustralia.
authors.forename: Jana
authors.initials: J
authors.lastname: Phan
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, University of Adelaide, Waite Campus, Urrbrae, SAAustralia; School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SAAustralia.
authors.forename: Kylie
authors.initials: K
authors.lastname: Neumann
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, University of Adelaide, Waite Campus, Urrbrae, SAAustralia; School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SAAustralia.
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Shirley
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hahn
authors.affiliation: School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SA Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Cozzolino
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, University of Adelaide, Waite Campus, Urrbrae, SAAustralia; School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SAAustralia.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Burton
keywords: Plantago; mucilage; mutagenesis; seed; spectroscopy; xylan