Kumaran Mande K, Bowman John L, Sundaresan Venkatesan
Institute of Molecular Agrobiology, National University of Singapore, Singapore 117604.
Plant Cell. 2002 Nov;14(11):2761-70. doi: 10.1105/tpc.004911.
The YABBY (YAB) genes specify abaxial cell fate in lateral organs in Arabidopsis. Loss-of-function mutants in two early-expressing YAB genes, FILAMENTOUS FLOWER (FIL) and YAB3, do not exhibit vegetative phenotypes as a result of redundancy. Mutations in these genes result in the derepression of the KNOX homeobox genes SHOOTMERISTEMLESS (STM), BREVIPEDICELLUS, and KNAT2 in the leaves and in the partial rescue of stm mutants. Here, we show that fil yab3 double mutants exhibit ectopic meristem formation on the adaxial surfaces of cotyledons and leaf blades. We propose that in addition to abaxial specification, lateral organ development requires YAB function to downregulate KNOTTED homeobox genes so that meristem initiation and growth are restricted to the apex.
YABBY（YAB）基因决定了拟南芥侧生器官的远轴细胞命运。两个早期表达的YAB基因，即丝状花（FIL）和YAB3，其功能缺失突变体由于冗余性而未表现出营养表型。这些基因的突变导致叶片中KNOX同源异型盒基因无茎分生组织（STM）、短叶柄和KNAT2的去抑制，并部分挽救了stm突变体。在这里，我们表明fil yab3双突变体在子叶和叶片的近轴表面出现异位分生组织形成。我们提出，除了远轴特化外，侧生器官发育还需要YAB功能来下调KNOTTED同源异型盒基因，从而将分生组织的起始和生长限制在顶端。
