Distinct Regulation of Adaxial-Abaxial Polarity in Anther Patterning in Rice
Distinct Regulation of Adaxial-Abaxial Polarity in Anther Patterning in Rice
复制标题
DOI：
10.1105/tpc.110.075291
复制
发表时间：
2010-05-01
期刊：
影响因子：
11.6
通讯作者：
Hirano, Hiro-Yuki
中科院分区：
文献类型：
--
作者：
Toriba, Taiyo;Suzaki, Takuya;Hirano, Hiro-Yuki
近轴-远轴极性的建立对侧器官的发育至关重要。在雄蕊中极性建立的机制仍然不清楚，而在叶中的极性建立的机制是很好理解的。在这里，我们调查了水稻（Oryza sativa）的杆状外稃（rol）突变体，其中雄蕊和外稃的发育严重受损。我们发现，外稃的杆状结构和被干扰的花药图案是由近轴-远轴极性调节缺陷造成的。基因分离表明，rol表型是由SHOOTLESS 2（SHL 2）中的弱突变引起的，SHL 2编码RNA依赖性RNA聚合酶，并在反式作用小干扰RNA（ta-siRNA）产生中起作用。因此，ta-siRNA可能在调控水稻花器官的近轴-远轴极性方面发挥重要作用。此外，我们还发现，在野生型花药发育过程中，近轴-远轴极性标记基因的空间表达模式发生了重排。在这种重新排列之后，一个新形成的极性很可能在一个新的发育单位（卵泡膜原基）中建立起来。这一观点得到了shl 2-rol突变体中异常雄蕊发育的观察结果的支持。相反，雄蕊花丝可能是通过离轴化形成的。因此，在雄蕊发育过程中，近轴-远轴极性的调节可能涉及一种独特的调节机制。
Establishment of adaxial-abaxial polarity is essential for lateral organ development. The mechanisms underlying the polarity establishment in the stamen remain unclear, whereas those in the leaf are well understood. Here, we investigated a rod-like lemma (rol) mutant of rice (Oryza sativa), in which the development of the stamen and lemma is severely compromised. We found that the rod-like structure of the lemma and disturbed anther patterning resulted from defects in the regulation of adaxial-abaxial polarity. Gene isolation indicated that the rol phenotype was caused by a weak mutation in SHOOTLESS2 (SHL2), which encodes an RNA-dependent RNA polymerase and functions in trans-acting small interfering RNA (ta-siRNA) production. Thus, ta-siRNA likely plays an important role in regulating the adaxial-abaxial polarity of floral organs in rice. Furthermore, we found that the spatial expression patterns of marker genes for adaxial-abaxial polarity are rearranged during anther development in the wild type. After this rearrangement, a newly formed polarity is likely to be established in a new developmental unit, the theca primordium. This idea is supported by observations of abnormal stamen development in the shl2-rol mutant. By contrast, the stamen filament is likely formed by abaxialization. Thus, a unique regulatory mechanism may be involved in regulating adaxial-abaxial polarity in stamen development.