Fucosylation, one of the key posttranslational modifications, plays an important role in plants. It is involved in the development, signal transduction, reproduction, and disease resistance. α1,3-/4-Fucosyltransferase is responsible for transferring L-fucose from GDP-L-fucose to the N-glycan to exert fucosylational functions. However, the roles of the fucosyltransferase gene in cotton remain unknown. This study provided a comprehensive investigation of its possible functions. A genome-wide analysis identified four, four, eight, and eight FucT genes presented in the four sequenced cotton species, diploid Gossypium raimondii, G. arboreum, tetraploid G. hirsutum acc. TM-1, and G. barbadense cv. H7124, respectively. These FucTs were classified into two groups, with FucT4 homologs alone as a group. We isolated FucT4 in TM-1 and H7124, and named it GhFucT4 and GbFucT4, respectively. Quantitative RT-PCR and transcriptome data demonstrated that GhFucT4 had the highest expression levels in fibers among all GhFucT genes. Association studies and QTL co-localization supported the possible involvement of GhFucT4 in cotton fiber development. GhFucT4 and GbFucT4 shared high sequence identities, and FucT4 had higher expression in H7124 fiber tissues compared with TM-1. Furthermore, ectopic expression of FucT4 in transgenic Arabidopsis promoted root cell elongation, upregulated expression of genes related to cell wall loosening, and led to longer primary root. These results collectively indicate that FucT4 plays an important role in promoting cell elongation and modulating fiber development, which could be utilized to improve fiber quality traits in cotton breeding.

岩藻糖基化是关键的翻译后修饰之一，在植物中起重要作用。它参与发育，信号转导，繁殖和抗病性。α1,3-/ 4-岩藻糖基转移酶负责将L-岩藻糖从GDP- L-岩藻糖转移至N-聚糖，从而发挥岩藻糖基化功能。然而，岩藻糖基转移酶基因在棉花中的作用仍然未知。这项研究提供了对其可能功能的全面调查。全基因组分析确定了四个测序棉种，二倍体提出了四个，四个，八个八个FUCT基因棉花雷蒙德氏棉，亚洲棉，四倍体陆地棉累计。TM-1和巴巴德木简历。分别为H7124。将这些FucTs分为两组，仅将FucT4同源物作为一组。我们孤立FucT4在TM-1和H7124，并把它命名为GhFucT4和GbFucT4分别。定量RT-PCR和转录组数据表明，在所有GhFucT基因中，GhFucT4在纤维中的表达水平最高。关联研究和QTL共同定位支持GhFucT4可能参与棉纤维发育。与TM-1相比，GhFucT4和GbFucT4具有高序列同一性，并且FucT4在H7124纤维组织中的表达更高。此外，异位表达转基因拟南芥中的FucT4促进根细胞伸长，上调与细胞壁松弛相关的基因的表达，并导致更长的原生根。这些结果共同表明，FucT4在促进细胞伸长和调节纤维发育中起重要作用，可用于改善棉花育种中的纤维品质性状。