Two-Dimensionality of Yeast Colony Expansion Accompanied by Pattern Formation

Yeasts can form multicellular patterns as they expand on agar plates, a phenotype that requires a functional copy of the FLO11 gene. Although the biochemical and molecular requirements for such patterns have been examined, the mechanisms underlying their formation are not entirely clear. Here we develop quantitative methods to accurately characterize the size, shape, and surface patterns of yeast colonies for various combinations of agar and sugar concentrations. We combine these measurements with mathematical and physical models and find that FLO11 gene constrains cells to grow near the agar surface, causing the formation of larger and more irregular colonies that undergo hierarchical wrinkling. Head-to-head competition assays on agar plates indicate that two-dimensional constraint on the expansion of FLO11 wild type (FLO11) cells confers a fitness advantage over FLO11 knockout (flo11Δ) cells on the agar surface.酵母菌在琼脂平板上扩张生长时，可形成多细胞结构表型，该表型的形成依赖于功能性拷贝的FLO11基因（FLO11 gene）。尽管针对这类结构形成的生化与分子必要条件已开展研究，但其具体形成机制仍未完全阐明。本研究开发了定量表征方法，可精准测定不同琼脂与糖浓度组合下酵母菌菌落的尺寸、形态及表面结构特征。我们将上述测量结果与数学及物理模型相结合，发现FLO11基因可限制细胞仅在琼脂表面附近生长，进而促使菌落体积更大、形态更不规则，并呈现出层级褶皱结构。琼脂平板上的直接竞争实验表明，FLO11野生型（FLO11 wild type）细胞在扩张过程中受到的二维空间限制，使其在琼脂表面上的适合度优于FLO11敲除（flo11Δ）细胞。