Coneva Viktoriya, Chitwood Daniel H
Donald Danforth Plant Science Center , St. Louis, MO, USA.
Front Plant Sci. 2015 Apr 24;6:287. doi: 10.3389/fpls.2015.00287. eCollection 2015.
Multicellularity has independently evolved numerous times throughout the major lineages of life. Often, multicellularity can enable complex, macroscopic organismal architectures but it is not required for the elaboration of morphology. Several alternative cellular strategies have arisen as solutions permitting exquisite forms. The green algae class Ulvophyceae, for example, contains truly multicellular organisms, as well as macroscopic siphonous cells harboring one or multiple nuclei, and siphonocladous species, which are multinucleate and multicellular. These diverse cellular organizations raise a number of questions about the evolutionary and molecular mechanisms underlying complex organismal morphology in the green plants. Importantly, how does morphological patterning arise in giant coenocytes, and do nuclei, analogous to cells in multicellular organisms, take on distinct somatic and germline identities? Here, we comparatively explore examples of patterning and differentiation in diverse coenocytic and single-cell organisms and discuss possible mechanisms of development and nuclear differentiation in the siphonous algae.
多细胞性在生命的主要谱系中已多次独立进化。通常，多细胞性能够形成复杂的宏观生物体结构，但形态的细化并不需要多细胞性。作为允许形成精致形态的解决方案，已经出现了几种替代的细胞策略。例如，绿藻纲中的石莼目包含真正的多细胞生物，以及具有一个或多个细胞核的宏观管状体细胞，还有多核且多细胞的管枝藻目物种。这些多样的细胞组织引发了许多关于绿色植物复杂生物体形态背后的进化和分子机制的问题。重要的是，巨大的多核细胞中形态模式是如何产生的，以及与多细胞生物中的细胞类似的细胞核是否具有不同的体细胞和生殖细胞身份？在这里，我们比较性地探讨了不同多核细胞和单细胞生物中的模式形成和分化实例，并讨论了管状体藻类中发育和核分化的可能机制。
