Department of Biochemistry and National Centre of Competence in Research, Chemical Biology, University of Geneva, Geneva, Switzerland.
Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France.
Curr Biol. 2022 May 9;32(9):1961-1973.e4. doi: 10.1016/j.cub.2022.03.018. Epub 2022 Mar 28.
Multicellularity evolved in fungi and animals, or the opisthokonts, from their common amoeboflagellate ancestor but resulted in strikingly distinct cellular organizations. The origins of this multicellularity divergence are not known. The stark mechanistic differences that underlie the two groups and the lack of information about ancestral cellular organizations limits progress in this field. We discovered a new type of invasive multicellular behavior in Fonticula alba, a unique species in the opisthokont tree, which has a simple, bacteria-feeding sorocarpic amoeba lifestyle. This invasive multicellularity follows germination dependent on the bacterial culture state, after which amoebae coalesce to form dynamic collectives that invade virgin bacterial resources. This bacteria-dependent social behavior emerges from amoeba density and allows for rapid and directed invasion. The motile collectives have animal-like properties but also hyphal-like search and invasive behavior. These surprising findings enrich the diverse multicellularities present within the opisthokont lineage and offer a new perspective on fungal origins.
多细胞生物在真菌和动物（后鞭毛生物）中从它们共同的变形虫祖先进化而来，但导致了截然不同的细胞组织。这种多细胞性分歧的起源尚不清楚。这两组之间存在明显的机械差异，而且关于祖细胞组织的信息有限，这限制了该领域的进展。我们在白绒盘菌中发现了一种新的侵袭性多细胞行为，这是后鞭毛生物树中的一个独特物种，它具有简单的、以细菌为食的变形虫索罗果生活方式。这种侵袭性多细胞性依赖于细菌培养状态的萌发，之后变形虫融合形成动态群体，侵入新的细菌资源。这种依赖细菌的社会行为源于变形虫密度，并允许快速和定向入侵。运动群体具有类似动物的特性，但也具有菌丝状的搜索和侵袭行为。这些令人惊讶的发现丰富了后鞭毛生物谱系中存在的多种多细胞性，并为真菌的起源提供了新的视角。
