背景回顾：Moderately rolled leaf is one of the target traits of the ideal plant architecture in rice breeding. Many genes, including homeodomain leucine zipper IV transcription factors ROC5 and ROC8, regulating rice leaf rolling have been cloned and functionally analyzed. 

提出问题：However, the molecular mechanism by which these genes modulate leaf-rolling remains largely elusive.

主要发现：In this study, we demonstrated the transcription activation activity of both ROC8 and ROC5.

结果1-功能鉴定：Overexpressing ROC8 caused adaxially rolled leaves due to decreased number and size of bulliform cells, whereas knockout of ROC8induced abaxially rolled leaves due to increased number and size of bulliform cells. 

结果2-ROC二聚化：ROC8 and ROC5 each could form homodimer, but ROC8 interacted preferably with ROC5 to form heterodimer. Importantly, we showed that the ROC8-ROC5 heterodimer rather than the homodimer of ROC8 or ROC5 was functional as neither overexpressing ROC8 in the ROC5 mutant nor overexpressing ROC5 in the ROC8-knockout line could rescue the mutant phenotype. This was further partially supported by the identification of a large number of common differentially-expressed-genes in single and double mutants of roc8 and roc5.

结果3-加性效应： ROC8 and ROC5 were functionally additive as the phenotype of abaxially rolled leaves was stronger in the roc5 roc8 double mutant than in their single mutants. 

结论：Our results provide evidence for the role of dimerization of ROC members in regulating leaf rolling of rice.

 摘 要 

适度的卷叶是水稻育种中理想植株结构的目标性状之一。以往的研究已经克隆并功能鉴定了包括HD Zip IV转录因子ROC5和ROC8在内的多个控制水稻叶片卷曲的基因。但是，这些基因通过何种分子机制调控水稻叶片卷曲还不清楚。本文中，作者揭示了ROC8和ROC5的转录激活活性。过表达ROC8基因会通过减少泡状细胞的数量和大小，导致近轴卷曲叶片；而ROC8敲除会通过增加泡状细胞的数量和大小，导致远轴卷曲叶片。ROC8和ROC5均可以各自形成同源二聚体，但是ROC8会优先与ROC5互作，形成异源二聚体。重要的是，作者发现相比于ROC8或者ROC5的同源二聚体，ROC8和ROC5形成的异源二聚体更有可能具有功能，并且无论是在ROC5功能缺失突变体中过表达ROC8，或者是在ROC8功能缺失突变体中过表达ROC5，均不能够恢复突变体的缺陷表型。通过对roc8和的roc5单突和双突植株的差异表达基因鉴定，发现存在很多重叠的差异表达基因，进一步证实了上述的结论。roc5 roc8双突植株的远轴叶片卷曲要比roc5或者roc8单突植株更加强烈，说明ROC8和ROC5的功能存在加性效应。本文的研究结果揭示了ROC蛋白通过二聚化调控水稻叶片卷曲的分子机制。