Effects of MIG1, TUP1 and SSN6 deletion on maltose metabolism and leavening ability of baker’s yeast in lean dough

Abstract

BackgroundGlucose repression is a global regulatory system in baker’s yeast. Maltose metabolism in baker’s yeast strains is negatively influenced by glucose, thereby affecting metabolite productivity (leavening ability in lean dough). Even if the general repression system constituted by MIG1, TUP1 and SSN6 factors has already been reported, the functions of these three genes in maltose metabolism remain unclear. In this work, we explored the effects of MIG1 and/or TUP1 and/or SSN6 deletion on the alleviation of glucose-repression to promote maltose metabolism and leavening ability of baker’s yeast.ResultsResults strongly suggest that the deletion of MIG1 and/or TUP1 and/or SSN6 can exert various effects on glucose repression for maltose metabolism. The deletion of TUP1 was negative for glucose derepression to facilitate the maltose metabolism. By contrast, the deletion of MIG1 and/or SSN6, rather than other double-gene or triple-gene mutations could partly relieve glucose repression, thereby promoting maltose metabolism and the leavening ability of baker’s yeast in lean dough.ConclusionsThe mutants of industrial baker’s yeast with enhanced maltose metabolism and leavening ability in lean dough were developed by genetic engineering. These baker’s yeast strains had excellent potential industrial applications.

MoTup1 is required for growth, conidiogenesis and pathogenicity of Magnaporthe oryzae

“…Disruption of TUPA , a Tup1 homologue, results in an opposite phenotype that reduces filamentation and promotes yeast phase growth in Penicillium marneffei (Todd et al ., ). Deletion of TUP1 is negative for glucose derepression, promoting maltose metabolism in S. cerevisiae (Lin et al ., ). Neurospore crassa Rco1, the homologue of Tup1, is required for hyphal fusion, normal hyphal morphology, and asexual and sexual development (Vandeputte et al ., ).…”

Effects of SNF1 on Maltose Metabolism and Leavening Ability of Baker's Yeast in Lean Dough

“…For health reasons, many people take the nonsugar or low‐sugar bread as their staple food. Maltose is the predominant sugar in lean dough, but for the great majority of baker's yeast strains, it can only be fermented after glucose depletion in bread making (Salema‐Oom and others ; Lin and others ). Glucose delays the uptake of other sugars and unnecessarily prolongs the production process by repressing the utilization of other carbon sources like maltose (Olsson and Nielsen ; Ahuatzi and others ; Usaite and others ).…”

“…Given that the maltose utilization level is the key factor for the leavening ability of baker's yeast in lean dough, an effective alleviation of glucose repression and a rapid transition from glucose to maltose metabolism is thus essential in improving the leavening ability (Randez‐Gil and others ; Salema‐Oom and others ). Previous work showed that compared with the wild type, the double‐gene deletions of MIG1 and SSN6 could generate a 12% increase in the leavening ability via effective glucose derepression (Lin and others ). However, the effects of modification on upstream regulatory factors such as the Snf1 protein kinase, relative to the repressors and the genes of maltose utilization, in glucose derepression and maltose metabolism of baker's yeast are unclear.…”

Effects of GLC7 and REG1 deletion on maltose metabolism and leavening ability of baker’s yeast in lean dough

“…Binding of Reg1p to Glc7p is enhanced in the presence of glucose and is required for glucose repression (Gadura et al, 2006). Effective alleviation of glucose repression could increase maltose metabolism (Lin et al, 2014). Our results show that deletions of GLC7 and/or REG1 could effectively alleviate glucose repression to improve maltose metabolism of baker's yeast (Fig.…”

“…Previous study has demonstrated that MIG1 and/or SSN6 (repressors) deletions could partially alleviate glucose repression to enhance maltose metabolism of baker's yeast (Lin et al, 2014). In this study, we focus on the effects of regulators (GLC7 encoding the catalytic and REG1 encoding the regulatory subunits of protein phosphatase type 1) of glucose repression on maltose metabolism and leavening ability.…”