Dataset Information

Anchorage by seed mucilage prevents seed dislodgement in high surface flow: a mechanistic investigation.

ABSTRACT:

Background and aims

Seed mucilage is a common and highly diverse trait shared among thousands of angiosperm species. While it has long been recognized that mucilage allows seeds to anchor to substrates (antitelechory), resisting abiotic and biotic dislodgement, we still lack a mechanistic understanding of this process.

Methods

We propose a mechanistic model of how mucilage affects substrate anchorage and fluid resistance, ultimately contributing to dislodgement resistance. To test this model, we subjected mucilaginous seeds of 52 species, varying in eight measured seed traits, to 7 d of continuous water flow at a range of dislodgement potentials.

Key results

Supporting our model, mucilage mass increased the force necessary to dislodge both dry and wet seeds; our measurement of the dislodgement force of dry mucilage explained time to dislodgement well. The effect size was remarkably large; increasing the standardized mucilage mass by 1 s.d. resulted in a 280-fold increase in the time to dislodgement. Fluid resistance was largely dependent on the speed of water flow and the seed's modified drag coefficient, but not seed traits. Neither mucilage expansion speed nor mucilage decay rate explained dislodgement potential well.

Conclusions

Our results suggest that the degree of anchorage to a substrate, measured with a simple dislodgement force assay, is highly predictive of mucilaginous seed retention in highly erosive environments. In contrast, we found that other seed and mucilage traits are of lesser importance to anchorage.

SUBMITTER: Pan VS

PROVIDER: S-EPMC9292590 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Anchorage by seed mucilage prevents seed dislodgement in high surface flow: a mechanistic investigation.

Pan Vincent S VS Girvin Cecilia C LoPresti Eric F EF

Annals of botany 20220701 7

<h4>Background and aims</h4>Seed mucilage is a common and highly diverse trait shared among thousands of angiosperm species. While it has long been recognized that mucilage allows seeds to anchor to substrates (antitelechory), resisting abiotic and biotic dislodgement, we still lack a mechanistic understanding of this process.<h4>Methods</h4>We propose a mechanistic model of how mucilage affects substrate anchorage and fluid resistance, ultimately contributing to dislodgement resistance. To test ...[more]

PMID: 35325924

Similar Datasets

Project description:Hydrated Arabidopsis thaliana seeds are coated by a gelatinous layer called mucilage, which is mainly composed of cell wall polysaccharides. Since mucilage is rich in pectin, its architecture can be visualized with the ruthenium red (RR) dye. We screened the seeds of around 280 Arabidopsis natural accessions for variation in mucilage structure, and identified a large number of novel variants that differed from the Col-0 wild-type. Most of the accessions released smaller RR-stained capsules compared to the Col-0 reference. By biochemically characterizing the phenotypes of 25 of these accessions in greater detail, we discovered that distinct changes in polysaccharide structure resulted in gelatinous coatings with a deceptively similar appearance. Monosaccharide composition analysis of total mucilage extracts revealed a remarkable variation (from 50 to 200% of Col-0 levels) in the content of galactose and mannose, which are important subunits of heteromannan. In addition, most of the natural variants had altered Pontamine Fast Scarlet 4B staining of cellulose and significantly reduced birefringence of crystalline structures. This indicates that the production or organization of cellulose may be affected by the presence of different amounts of hemicellulose. Although, the accessions described in this study were primarily collected from Western Europe, they form five different phenotypic classes based on the combined results of our experiments. This suggests that polymorphisms at multiple loci are likely responsible for the observed mucilage structure. The transcription of MUCILAGE-RELATED10 (MUCI10), which encodes a key enzyme for galactoglucomannan synthesis, was severely reduced in multiple variants that phenocopied the muci10-1 insertion mutant. Although, we could not pinpoint any causal polymorphisms in this gene, constitutive expression of fluorescently-tagged MUCI10 proteins complemented the mucilage defects of a muci10-like accession. This leads us to hypothesize that some accessions might disrupt a transcriptional regulator of MUCI10. Therefore, this collection of publicly-available variants should provide insight into plant cell wall organization and facilitate the discovery of genes that regulate polysaccharide biosynthesis.

Project description:The plant cell wall is held together by the interactions between four major components: cellulose, pectin, hemicellulose, and proteins. Mucilage is a powerful model system to study the interactions between these components as it is formed of polysaccharides that are deposited in the apoplast of seed coat epidermal cells during seed development. When seeds are hydrated, these polysaccharides expand rapidly out of the apoplastic pocket, and form an adherent halo of mucilage around the seed. In Arabidopsis, mutations in multiple genes have similar loss of mucilage adherence phenotypes including CELLULOSE SYNTHASE 5 (CESA5)/MUCILAGE-MODIFIED 3 (MUM3), MUM5/MUCI21, SALT-OVERLY SENSITIVE 5 (SOS5), and FEI2. Here, we examine the interactions between these factors to better understand how they participate to control mucilage adherence. Double mutant phenotypes indicated that MUM5 and CESA5 function in a common mechanism that adheres pectin to the seed through the biosynthesis of cellulose and xylan, whereas SOS5 and FEI2, encoding a fasciclin-like arabinogalactan protein or a receptor-like kinase, respectively, function through an independent pathway. Cytological analyses of mucilage indicates that heteromannans are associated with cellulose, and not in the pathway involving SOS5 or FEI2. A SOS5 fluorescent protein fusion (SOS5-mCITRINE) was localized throughout the mucilage pocket, consistent with a structural role in pectin adhesion. The relationship between SOS5 and FEI2 mediated mucilage adherence was examined in more detail and while sos5 and fei2 mutants show similar phenotypes, key differences in the macromolecular characteristics and amounts of mucilage polymers were observed. FEI2 thus appears to have additional, as well as overlapping functions, with SOS5. Given that FEI2 is required for SOS5 function, we propose that FEI2 serves to localize SOS5 at the plasma membrane where it establishes interactions with mucilage polysaccharides, notably pectins, required for mucilage adherence prior to SOS5 being released into the apoplast.

Dataset Information

Anchorage by seed mucilage prevents seed dislodgement in high surface flow: a mechanistic investigation.

Background and aims

Methods

Key results

Conclusions

Publications

Anchorage by seed mucilage prevents seed dislodgement in high surface flow: a mechanistic investigation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets