大背景：Plant-specific WOX family transcription factors play important roles ranging from embryogenesis to lateral organ development. 

小背景+问题：The WOX1 transcription factors, which belong to the modern clade of the WOX family, are known to regulate outgrowth of the leaf blade specifically in the mediolateral axis; however, the role of WOX1 in compound leaf development remains unknown. 

结果1-基因家族分析：Phylogenetic analysis of the whole WOX family in tomato (Solanum lycopersicum) indicates that there are 10 members that represent the modern, intermediate, and ancient clades. 

结果2-番茄WOX1基因：Using phylogenetic analysis and a reverse genetic approach, in this study we identified SlLAM1 in the modern clade and examined its function and tissue-specific expression pattern. 

结果3-基因敲除：We found that knocking out SlLAM1 via CRISPR/Cas9-mediated genome editing led to narrow leaves and a reduced number of secondary leaflets. 

结果4-过表达：Overexpression of tomato SlLAM1 could rescue the defects of the tobacco lam1 mutant. 

结果5-突变体转录组：Anatomical and transcriptomic analyses demonstrated that floral organ development, fruit size, secondary leaflet initiation, and leaf complexity were altered due to loss-of-function of SlLAM1. 

结论：These findings demonstrate that tomato SlLAM1 plays an important role in the regulation of secondary leaflet initiation, in addition to its conserved function in blade expansion.

 摘 要 

植物特异性WOX家族转录因子在植物从胚胎发生到侧生器官发育过程中均发挥重要作用。WOX1转录因子属于WOX家族的现代分枝，已有研究显示WOX1作用于叶片，尤其是中侧轴叶片的向外生长。但是，WOX1在复杂叶发育过程中的作用还不清楚。对于番茄WOX家族的系统发育分析显示，番茄中存在10个WOX家族成员，分属于现代、中间和远古分枝。利用系统发育分析和反向遗传学分析，作者鉴定了番茄WOX现代分枝中的SlLAM1基因的功能，并发现了其组织特异性的表达模式。作者发现通过CRISPR/Cas9介导的基因组编辑技术，敲除SlLAM1基因后，导致突变体的叶片变窄，次生小叶数目减少。过表达番茄SlLAM1基因能够恢复烟草lam1突变体的缺陷。解剖学和转录组学分析表明，SlLAM1的功能丧失导致花器官发育、果实大小、次生小叶起始和叶片复杂性发生改变。本文的研究揭示了番茄SlLAM1基因除了其在叶片扩张中的保守作用，该基因还作用于次生小叶起始的调控。