Molecular basis of photoperiod-sensitive cytoplasmic male sterility in wheat

小麦新品系的异质系。Norin 26(N26)具有野生近缘种山羊草的细胞质，在长日照条件下(光照15h)，表现出雌雄同性的雄蕊转化为雌蕊状结构。这种现象被命名为光周期敏感型细胞质雄性不育(PCMS)，并研究开发一种新的杂交小麦生产系统。与n26相反，小麦cv.由于Rfd1基因位于7B染色体长臂上，中国春没有表现出PCMS。本研究的目的是阐明PCMS1的分子基础。对Rfd1功能丧失的研究表明，Ae.厚朴细胞质实质上诱导雌蕊不依赖于长光周期。同源胞质n26在短日照条件下的育性恢复可能是由防止Ae影响的基因(S)控制的。在短光周期下起作用的粗面细胞质。对小麦MADS盒基因的分析表明，异质系雄蕊原基中B类MADS盒基因的表达不足是造成雌雄同源的原因。线粒体与雌蕊相关基因的消减研究表明，Cox1基因和ATPA嵌合基因在雌蕊系中优先表达。这表明这些线粒体基因产物与异质系雌蕊的诱导有关。根据本研究的结果，阐明了利用PCMS选育杂交种在实际育种中需要解决的问题。

The alloplasrmic line of wheat cv. Norin 26 (N26) with the cytoplasm of a wild relative species Aegilops crass shows pistillody, homoerotic transformation of stamens into pistil-like structures, when grown under long-day conditions (>15 h light). This phenomenon was named photoperiod-sensitive cytoplasmic male sterility (PCMS) and studies to develop a new hybrid wheat production system. Contrary to N26, wheat cv. Chinese Spring (CS) does not show the PCMS because of the presence of Rfd1 gene located on the long arm of chromosome 7B. The objective of this research project is to elucidate the molecular basis of the PCMS.1. Pistillody in the linesA loss-of function study of Rfd1 using ditelosomic 7BL alloplasmic line revealed that the Ae. Crassa cytoplasm essentially induces the pistillody independent of long photoperiod. The fertility restoration under the short-day conditions in the alloplasmic N26 could be controlled by gene(s) preventing the influence of the Ae. Crassa cytoplasm which functions under short photoperiod.2. Wheat MADS box genesAnalyses of wheat MADS box genes revealed that the pistillody is caused by the deficiency of class B MADS box gene expression in the stamen primordia of the alloplasmic lines.3. Mitochondrial genes associated with the pistillodyA subtraction study indicated that coxl gene and atpA chimeric gene are preferentially expressed in the pistillody line. This suggests that these mitochondrial gene products are associated with the induction of pistillody in the alloplasmic lines.Hybrid wheat breeding using the PCMSAccording to the results of present research, the problems to be solved for practical hybrid wheat breeding were clarified.