Department of Genetics and Applied Microbiology, University of Debrecen, Debrecen, Hungary.
Sci Rep. 2024 Nov 29;14(1):29677. doi: 10.1038/s41598-024-80436-9.
The ability to produce pulcherriminic acid is a characteristic feature of yeast species of the pulcherrima clade recently merged under the taxonomic name Metschnikowia pulcherrima. This iron chelator cyclodipeptide forms pulcherrimin, a maroon-red pigment with ferric ions. Its synthesis and secretion into the environment is under the control of closely linked genes referred to as the PUL cluster. The examination of 18 generations of single-cell clones generated from a stock culture of the collection strain 11-1090 (CBS 10359) in this study revealed that the biosynthesis of pulcherriminic acid is reversibly switched on and off during the propagation of cells in a way similar to the epigenetic silencing and activation of gene expression (bimodal active/silent state) in near-heterochromatic regions of other yeast species. As the strain is heterozygous for PUL2 alleles encoding slightly different amino acid sequences and has a plastic genome structure, the efficiency of pulcherriminic acid synthesis in the switched-on state is presumed to depend on which PUL2 allele is active and on structural changes in the genome. The transitions between the active and silent states of pulcherriminic acid synthesis are associated with transitions between the active and silent states of antimicrobial antagonism. This association confirms the primary role of pulcherriminic acid in the antimicrobial antagonism of M. pulcherrima.
产生美丽霉素的能力是最近被归为美丽弯颈霉分类群中酵母物种的特征。这种铁螯合环二肽形成美丽霉素，一种与铁离子结合的棕红色色素。它的合成和分泌到环境中受紧密连锁的基因控制，这些基因被称为 PUL 簇。本研究对从收藏菌株 11-1090（CBS 10359）的储备培养物中产生的 18 代单细胞克隆进行了检查，结果表明，在细胞繁殖过程中，美丽霉素酸的生物合成可被可逆地打开和关闭，类似于其他酵母物种中近异染色质区域的基因表达的表观遗传沉默和激活（双峰有活性/无活性状态）。由于该菌株在编码略有不同氨基酸序列的 PUL2 等位基因上是杂合的，并且具有可塑的基因组结构，因此推测在打开状态下合成美丽霉素酸的效率取决于哪个 PUL2 等位基因是有活性的，以及基因组中的结构变化。美丽霉素酸合成的有活性和无活性状态之间的转变与抗菌拮抗作用的有活性和无活性状态之间的转变相关。这种关联证实了美丽霉素酸在美丽弯颈霉抗菌拮抗作用中的主要作用。
