On the cover: Developmental Cell is 25 years old! We are celebrating this anniversary with a collection of commissioned content that reflects the diverse interests of the journal. Our cover illustration depicts the remarkable journey a single cell can take as it develops into different organs and organisms. The right branches highlight the inner workings that are essential to this process, keep cells operational or remove them, and can go awry during disease. Image credit: Julie Sung.

PC:安徽农业大学揭示生长素信号途径的新机制

一类小型RNA——相位小干扰RNA（phasiRNAs）——特异性表达于单子叶植物的花药中，且与雄性育性密切相关；本研究鉴定出一种具有功能性的5′-A型phasiRNA（命名为osphasiR1_1），该RNA通过介导OsARF7转录本的切割来促进雄性育性。采用 CRISPR –Cas9基因敲除技术及短串联靶标模拟物敲低osphasiR1_1后，雄性育性和结实率均显著降低。

进一步的机制研究表明，osphasiR1_1通过介导OsARF7的切割并以依赖于OsAGO2、但不依赖于MEL1/OsAGO5c的方式促进雄性育性。OsARF7具有转录激活活性，其过表达可过度激活靶基因，例如关键育性相关基因——biquitin-fusion ribosomal protein L40 4 and heat shock protein 70-4.。

小结：本研究揭示了osphasiR1_1–OsAGO2–OsARF7这一调控模块在单子叶植物中控制雄性育性的分子机制。

原文：A phased small interfering RNA acts in an OsAGO2-dependent manner to mediate OsARF7 cleavage and promote male fertility in rice