Cellulose Accumulation and a Cellulose Synthase Gene are Responsible for Cell Aggregation in the Cyanobacterium Thermosynechococcus vulcanus RKN

Abstract

A thermophilic cyanobacterium, Thermosynechococcus vulcanus RKN, exhibits cell aggregation under low temperature illuminated conditions as a means of physiological acclimation to avoid excess light stress. The cell aggregation was dispersed with cellulase treatment. We developed a method to quantify small amounts of cellulose by partial cellulose purification followed by quantitation of liberated glucose by cellulase. Under low temperature illuminated light conditions, cellulose accumulation was induced approximately 2-fold, to 10 μg (4 × 10(9) cells)(-1), and slightly preceded aggregation. Based on sequence similarity, three candidate genes for cellulose synthase (Tvtll0007, Tvtlr1795 and Tvtlr1930-33) were cloned from T. vulcanus. Gene disruption analysis showed that only Tvtll0007 was responsible for both the light- and low temperature-induced cell aggregation and the induction of cellulose accumulation. Gene expression analysis suggested that the low temperature illuminated conditions quickly induced expression of Tvtlr1795 and Tvtlr1930-33, while the induction of Tvtll0007 was slow. These results suggest that Tvtll0007 encodes a functional cellulose synthase whose activity may not be regulated at the transcriptional level.

Three cyanobacteriochromes work together to form a light color-sensitive input system for c-di-GMP signaling of cell aggregation

“…In contrast to the very closely related T. elongatus, T. vulcanus shows cellulose-dependent cell aggregation under blue light and at a low temperature (31°C) that is not optimal for viability and replication (8,24). To assess the roles of T. vulcanus SesA, SesB, and SesC in cell aggregation, we disrupted their genes to create strains that lack sesA and/or sesB and/or sesC (ΔsesA, ΔsesB, and ΔsesC, respectively).…”

“…The cellulose synthase T. vulcanus Tll0007, which has also been shown to be essential for cell aggregation (24), contains a c-di-GMP-binding domain (25,26) and may be the downstream acceptor for SesA-produced c-di-GMP. In addition, although Thermosynechococcus spp.…”

The effect of phytohormones on the growth, cellulose production and pellicle properties of Gluconacetobacter xylinus ATCC 53582

“…The cellulose biofilm produced by this organism has been the subject of intense investigation due to its purity, mechanical strength, and high crystallinity. [3][4][5][6][7][8][9][10][11] These properties make bacterial cellulose useful for a variety of industrial applications. 3,[12][13][14][15] Despite decades of study, the complete cellulose biosynthetic pathway has not yet been elucidated; there is still much to learn about its regulation, export mechanisms and assembly into the crystallized form.…”

CugP Is a Novel Ubiquitous Non-GalU-Type Bacterial UDP-Glucose Pyrophosphorylase Found in Cyanobacteria

“…However, it is unknown if they are essential for survival. Cellulose is selectively deposited in a thermophilic cyanobacterium, Thermosynechococcus, under conditions of low temperature and light (23). So, a CugP-type Tlr0611 appears to be the sole enzyme to provide UDP-Glc for biosynthesis of cellulose and might be induced under such conditions in this cyanobacterium.…”

“…However, such a GalU-type enzyme is not present in all cyanobacteria. Specifically, although Thermosynechococcus is reported to possess a cellulose synthase to produce cellulose under conditions of light and low temperature (23), a GalU-type gene that could supply UDP-Glc to this cellulose has not been found in its genome (24). Given these observations, we hypothesized that an uncharacterized non-GalU-type UDP-Glc PPase may exist in such cyanobacteria.…”