National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
Planta. 2013 Oct;238(4):643-55. doi: 10.1007/s00425-013-1916-y. Epub 2013 Jun 21.
Tomato fruit-weight 2.2 (FW2.2) was reported to control up to 30 % fruit weight. Recent studies demonstrated that FW2.2-like (FWL) genes also play important roles in plant growth and development. For instance, a maize homolog of FW2.2, named cell number regulator 1 (CNR1), negatively regulates plant and organ size. However, FWL genes in rice have not been characterized yet. In this study, eight FWL genes were identified in rice genome and designated as OsFWL1-8. The chromosome location, gene structure, protein motif, and phylogenetic relationship of OsFWL genes were analyzed. RT-PCR result and microarray data revealed that OsFWL genes exhibited diverse expression patterns and the detailed expression patterns of OsFWL5, 6, and 7 negatively correlated with leaf growth activity. Rice protoplast transient transformation experiment showed that most OsFWL proteins locate at cell membrane but OsFWL8 is present in the nucleus. In addition, the functions of OsFWL genes were investigated by analyzing two T-DNA insertion lines for OsFWL3 and 5. Compared with wild type, the grain weight of osfwl3 mutant and the plant height of osfwl5 mutant were increased by 5.3 and 12.5 %, respectively. We also found that the increase in grain length of osfwl3 mutant was due chiefly to incremental cell number, not cell size and the expression of OsFWL3 negatively correlated with glume growth activity. These results provide a comprehensive foundation for further study of OsFWL functions in rice.
番茄果实重量 2.2 号（FW2.2）被报道可控制高达 30%的果实重量。最近的研究表明，FW2.2 样（FWL）基因在植物生长和发育中也起着重要作用。例如，玉米 FW2.2 的同源物，命名为细胞数量调节因子 1（CNR1），负调控植物和器官大小。然而，水稻中的 FWL 基因尚未被表征。在这项研究中，在水稻基因组中鉴定了 8 个 FWL 基因，并将其命名为 OsFWL1-8。分析了 OsFWL 基因的染色体位置、基因结构、蛋白基序和系统发育关系。RT-PCR 结果和微阵列数据显示，OsFWL 基因表现出不同的表达模式，OsFWL5、6 和 7 的详细表达模式与叶片生长活性呈负相关。水稻原生质体瞬时转化实验表明，大多数 OsFWL 蛋白定位于细胞膜，但 OsFWL8 存在于细胞核中。此外，通过分析 OsFWL3 和 5 的两个 T-DNA 插入系来研究 OsFWL 基因的功能。与野生型相比，osfwl3 突变体的粒重增加了 5.3%，osfwl5 突变体的株高增加了 12.5%。我们还发现，osfwl3 突变体粒长的增加主要是由于细胞数量的增加，而不是细胞大小，并且 OsFWL3 的表达与颖片生长活性呈负相关。这些结果为进一步研究 OsFWL 在水稻中的功能提供了全面的基础。
