Contribution of the β‐glucosidase BglC to the onset of the pathogenic lifestyle of Streptomyces scabies

Abstract

2Common scab disease on root and tuber plants is caused by Streptomyces scabies and related 2 3 species which use the cellulose synthase inhibitor thaxtomin A as main phytotoxin. 4Thaxtomin production is primarily triggered by the import of cello-oligosaccharides. Once 2 5 inside the cell, the fate of the cello-oligosaccharides is dichotomized into i) fueling glycolysis 2 6with glucose for the saprophytic lifestyle through the action of β -glucosidase(s) (BG), and ii) reduced production of thaxtomin when the mutant was cultivated on media containing cello- mediated induction of thaxtomin production and suggests that the role of BglC in the route to 4 0 the pathogenic lifestyle of S. scabies is more complex than currently presented.

β-Glucosidase VmGlu2 Contributes to the Virulence of Valsa mali in Apple Tree

“…The role of CWDEs in the virulence of plant pathogens has been described by previous studies, while these enzymes are considered vital for the generation of disease symptoms and pathogenesis (Brito et al, 2006;Kubicek et al, 2014;Pérez-Hernández et al, 2017;Gui et al, 2018). The β-glucosidases are among the main CWDEs, and thus play important roles especially in the virulence of necrotrophic pathogens infection and disease development (Sasaki and Nagayama, 1996;Pérez-Hernández et al, 2017;Jourdan et al, 2018). V. mali, the causal agent of apple tree Valsa canker, infects host plants and causes typical symptoms through secreted CWDEs and toxins.…”

“…Thaxtomin is the main phytotoxin produced by S. scabies. However, the underlying mechanism of BglC in the virulence of S. scabies is more complex than commonly perceived (Jourdan et al, 2018).…”

“…In B. cinerea, the positive correlation was found between the β-glucosidase activities and the pathogenicity Nagayama, 1994, 1996), while the deletion of BcSUN1, encoding a β-glucosidase, had a marked effect on the production of reproductive structures as well as the ability of the pathogen to infect bean, tomato and tobacco plants (Pérez-Hernández et al, 2017). Jourdan et al (2018) demonstrated that β-glucosidase BglC plays an important role in the virulence of Streptomyces scabies, by affecting the intracellular accumulation of signals that trigger the thaxtomin A biosynthesis. Thaxtomin is the main phytotoxin produced by S. scabies.…”

Recent advances in natural products exploitation in Streptomyces via synthetic biology

“…Over the past decades, a set of in vivo genome editing methods have been developed to facilitate pathway engineering and modification. However, previous studies for genome editing in Streptomyces were mainly based on the traditional double crossover or single crossover . Luckily, with the advent of CRISPR systems, tools for site‐specific genome editing in Streptomyces were rapidly developed (Figure ).…”

“…Previous work demonstrated that cebR is the cellobiose‐sensing key, which locks the expression of txtR , while txtR is the key necessary to unlock the production of phytotoxin . With the understanding of the regulation relationship between the regulons cebR and txtR , the constitutive thaxtomin A production and hypervirulence of Streptomyces scabies were obtained by the cebR deletion . In addition, the increase of milbemycin production was attributed to the deletion of SbbA in the SbbR/SbbA pair (an important ArpA/AfsA ‐like system) in a BGC from Streptomyces bingchenggensis BC04 .…”