Abstract Detail

Cell biology

Wasteneys, Geoff [1], Fujita, Miki [1], Mulvihill, Adam [1].

Cellulose Microfibril Crystallinity Implicates Cellulose Synthesis and Xyloglucan Interactions for Partial Regulation of Anisotropic Growth.

In Arabidopsis thaliana, the cell wall, amongst its many functions, acts as a regulator of anisotropic growth. Extant hypotheses and data place emphasis on the constituents of the wall, mainly the crystalline cellulose microfibrils and tethering hemicelluloses. Arranged in an anti-parallel, transverse array in elongating cells, the microfibrils often mirror what many consider microtubule “tracks.” Previous work with a temperature sensitive mutant in microtubule dynamics (mor1-1) and one in cellulose synthase function (any1) showed that both have reduced anisotropic growth, resulting in radial swelling. Here we use near-TIRF microscopy, a technique in which internally reflected fluorescent light of varying angles can illuminate fluorophores in different layers of the cell. Fluorescently tagged tubulin and CesA6, a subunit of the cellulose producing Cellulose Synthase Complex (CSC), can be visualized in real-time simultaneously with this technique. From past work, a relationship emerged between the degree of crystallinity of the microfibrils of the wall, the velocity of the CSC, and the mass of tubulin in polymer form. Considering absolute cellulose content remained undisturbed, the chemical and physical qualities of the microfibrils themselves have been called into question as regulators of unilateral growth. The crystalline nature of the microfibrils could regulate or be regulated by potential interactions with xyloglucans in the cell wall, making work with the same transgenic reporters in known Xyloglucan xylosyltransferase mutants (xxt1/xxt2) of high interest. By using near-TIRF and kymograph analysis, a plugin allowing for a read of particle speed by displaying movement as time over distance, we aim to confirm the relationship between microfibril synthesis and microtubule dynamics illustrated previously. Further, we wish to elucidate the spatial distribution of xyloglucan in the wall and its relationship with microtubules and cellulose synthesis via epitope immunolabeling of thick sections.

1 - UBC, Botany, Room #3529 - 6270 University Boulevard , Vancouver, BC, V6T 1Z4 , Canada

Keywords:
Cellulose
Polarized growth
Anisotropy
Microtubules
Cortical Microtubules
CSC
xyloglucan.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PCL005
Abstract ID:810
Candidate for Awards:None