Pantothenate auxotrophy in a naturally occurring biocontrol yeast

Abstract

The genus Hanseniaspora is characterized by some of the smallest genomes among budding yeasts. These fungi are primarily found on plant surfaces and in fermented products and represent promising biocontrol agents against notorious fungal plant pathogens. In this work, we identify a Hanseniaspora meyeri isolate that shows strong antagonism against the plant pathogen Fusarium oxysporum as a pantothenate auxotroph. Furthermore, strong biocontrol activity in vitro required both pantothenate and biotin in the growth medium. We show that the H. meyeri isolate APC 12.1 can obtain the vitamin from plants and other fungi. The underlying reason for the auxotrophy is the lack of key pantothenate biosynthesis genes, but at least six genes encoding putative pantothenate transporters are present in the genome. By constructing and using a Saccharomyces cerevisiae reporter strain, we identified one Hanseniaspora transporter, out of the six candidate proteins, that conferred pantothenate uptake activity to S. cerevisiae. Pantothenate auxotrophy is rare and has only been described in a few bacteria and in S. cerevisiae strains that were isolated from sake. Such auxotrophic strains may seem an unexpected and unlikely choice as potential biocontrol agents, but they may be particularly competitive in their ecological niche and their specific growth requirements are an inherent biocontainment strategy preventing uncontrolled growth in the environment. Auxotrophic strains such as the H. meyeri isolate APC 12.1 may thus represent a new strategy for developing biocontrol agents that will be easier to register than prototrophic strains, which are normally used for such applications.

Gene loss and cis-regulatory novelty shaped core histone gene evolution in the apiculate yeastHanseniaspora uvarum

“…(Hamby et al 2012;Becher et al 2018;Saubin et al 2020). Hanseniaspora has also gained interest in biotechnology applications, such as expanding the sensorial complexities of fermented products (Steensels and Verstrepen 2014) and as natural biocontrol agents (Rueda-Mejia et al 2022). Among Hanseniaspora spp., Hanseniaspora uvarum, a species in the FEL, has become a focus for research and biotechnological development (Badura et al 2021(Badura et al , 2023Heinisch et al 2023;Van Wyk et al 2023).…”

“…2020) . Hanseniaspora has also gained interest in biotechnology applications, such as expanding the sensorial complexities of fermented products (Steensels and Verstrepen 2014) and as natural biocontrol agents (Rueda-Mejia et al . 2022).…”