Phytochrome-mediated regulation of cell division and growth during regeneration and sporeling development in the liverwort Marchantia polymorpha
Phytochrome-mediated regulation of cell division and growth during regeneration and sporeling development in the liverwort Marchantia polymorpha
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DOI：
10.1007/s10265-015-0724-9
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发表时间：
2015-04
影响因子：
2.8
通讯作者：
R. Nishihama;K. Ishizaki;Masashi Hosaka;Yoriko Matsuda;Akane Kubota;T. Kohchi
中科院分区：
文献类型：
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作者：
R. Nishihama;K. Ishizaki;Masashi Hosaka;Yoriko Matsuda;Akane Kubota;T. Kohchi
在无根植物的整个生命周期中，光调节着发育的各个方面。光感受器，如红色(R)和远红色（FR）光感受器光敏色素，在调节发育程序中起着关键作用。植物具有高度的发育可塑性，可以从各种细胞中再生组织、器官和整个身体。在陆地植物中，苔藓植物在无激素条件下表现出非凡的再生能力。光作为一种环境因子，在苔藓植物的再生过程中起着至关重要的作用。然而，光如何调节再生仍然未知。在这里，我们展示了使用含有单个光敏色素基因的多态地衣（marchantia polymorpha），光敏色素调节新再生组织的细胞周期和细胞形状。我们的形态学和细胞学观察表明，在黑暗或光敏色素失活的R/FR循环照射条件下，体块外植体腹表面中脉周围g1阻滞的表皮细胞的s期进入被大大延迟，然而，在那里最终形成了小的，侧向狭窄的再生体。因此，与一个多世纪前发表的早期描述一致，光对m的再生不是必不可少的，但对m的再生有深远的影响。polymorpha。在R/FR循环条件下生长的再生细胞比在R循环条件下生长的再生细胞更长、更窄。本构活性突变体的表达。即使在黑暗中，当有糖供应时，多态光敏色素也能使生长良好、广泛扩张的菌体再生，进一步证明光敏色素信号促进细胞增殖，而细胞增殖的速度受蔗糖供应的限制。R和FR辐照对孢子的细胞分裂和伸长也有类似的影响。因此，除了激活光合作用外，R在m再生中的主要作用。多形性通过光敏色素促进圆形细胞的增殖，其机制可能在散裂中起作用。
Light regulates various aspects of development throughout the life cycle of sessile land plants. Photoreceptors, such as the red (R) and far-red (FR) light receptors phytochromes, play pivotal roles in modulating developmental programs. Reflecting high developmental plasticity, plants can regenerate tissues, organs, and whole bodies from varieties of cells. Among land plants, bryophytes exhibit extraordinary competency of regeneration under hormone-free conditions. As an environmental factor, light plays critical roles in regeneration of bryophytes. However, how light regulates regeneration remains unknown. Here we show that using the liverwortMarchantia polymorpha, which contains a single phytochrome gene, the phytochrome regulates re-entry into the cell cycle and cell shape in newly regenerating tissues. Our morphological and cytological observations revealed that S-phase entry of G1-arrested epidermal cells around the midrib on the ventral surface of thallus explants was greatly retarded in the dark or under phytochrome-inactive R/FR cycle irradiation conditions, where, nevertheless, small, laterally narrow regenerants were eventually formed. Thus, consistent with earlier descriptions published over a century ago, light is not essential for, but exerts profound effects on regeneration inM. polymorpha. Ventral cells in regenerants grown under R/FR cycle conditions were longer and narrower than those under R cycle. Expression of a constitutively active mutant ofM. polymorphaphytochrome allowed regeneration of well grown, widely expanded thalli even in the dark when sugar was supplied, further demonstrating that the phytochrome signal promotes cell proliferation, which is rate-limited by sucrose availability. Similar effects of R and FR irradiation on cell division and elongation were observed in sporelings as well. Thus, besides activation of photosynthesis, major roles of R in regeneration ofM. polymorphaare to facilitate proliferation of rounder cells through the phytochrome by mechanisms that are likely to operate in the sporeling.