David Russo | Exploring cyanobacterial secretion for ecology and biotechnology
Channel: CyanoWorld
Date: 2021-07-14

David Russo - Friedrich Schiller University Jena, Germany

Homepage: https://david-a-russo.netlify.app/
Twitter: https://twitter.com/russo__da
Research Gate: https://www.researchgate.net/profile/David-Russo-3

Exploring cyanobacterial secretion for ecology and biotechnology

One of the major strategies through which cyanobacteria respond to external stimuli is the production and release of a large repertoire of small molecules and proteins. The release of these compounds is termed secretion. Genomic analyses indicate that secretion systems are widely abundant in the phylum, however little is known regarding their function and regulation. In my work, I aim to describe how cyanobacteria use secretion to interact with their environment and associated microbiome and how to use this information to develop novel biotechnological applications.

Previously, the fast-growing cyanobacterium Synechococcus elongatus UTEX 2973 was used to express and secrete the industrially relevant enzyme TfAA10A, a lytic polysaccharide monooxygenase (LPMO) from the gram-positive bacterium Thermobifida fusca. TfAA10A was recognized by the cyanobacterial secretion machinery and virtually all the protein was directed to the culture medium with a secretion yield estimated at 779 ± 40 µg L-1. We hypothesized the type IV pilus system may be involved in protein secretion. Type IV pili (T4P) have been shown to be crucial for twitching motility, DNA uptake and they also have considerable homology to type II secretion systems. However, whether the T4P constitutes a de facto secretion system remains an open question.

In order to further investigate the potential role of T4P in cyanobacterial secretion, Synechocystis sp. PCC 6803, a model for cyanobacterial T4P studies, was chosen. A nanoluciferase-based secretion reporter was established and expressed in a collection of Synechocystis sp. PCC 6803 T4P mutants to provide a quantitative measure of secretion. Interestingly, results show that mutations to the T4P can have both positive and negative effects on secretion levels. I will discuss the implication of these results within the context of what is currently known about protein secretion in cyanobacteria.

This talk is part of the CyanoWorld online seminar series, hosted by Nicolas Schmelling and Ilka Axmann, and was held on Zoom on May 27th, 2021.

Follow Us on Twitter: https://twitter.com/CyanoWorld1