Niu Erli, Shang Xiaoguang, Cheng Chaoze, Bao Jianghao, Zeng Yanda, Cai Caiping, Du Xiongming, Guo Wangzhen
State Key Laboratory of Crop Genetics & Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center, Ministry of Education, Nanjing Agricultural University, Nanjing, Jiangsu, China.
State Key Laboratory of Cotton Biology, Cotton Research Institute, Chinese Academy of Agricultural Sciences, Anyang, Henan, China.
PLoS One. 2015 Dec 28;10(12):e0145725. doi: 10.1371/journal.pone.0145725. eCollection 2015.
COBRA-Like (COBL) genes, which encode a plant-specific glycosylphosphatidylinositol (GPI) anchored protein, have been proven to be key regulators in the orientation of cell expansion and cellulose crystallinity status. Genome-wide analysis has been performed in A. thaliana, O. sativa, Z. mays and S. lycopersicum, but little in Gossypium. Here we identified 19, 18 and 33 candidate COBL genes from three sequenced cotton species, diploid cotton G. raimondii, G. arboreum and tetraploid cotton G. hirsutum acc. TM-1, respectively. These COBL members were anchored onto 10 chromosomes in G. raimondii and could be divided into two subgroups. Expression patterns of COBL genes showed highly developmental and spatial regulation in G. hirsutum acc. TM-1. Of them, GhCOBL9 and GhCOBL13 were preferentially expressed at the secondary cell wall stage of fiber development and had significantly co-upregulated expression with cellulose synthase genes GhCESA4, GhCESA7 and GhCESA8. Besides, GhCOBL9 Dt and GhCOBL13 Dt were co-localized with previously reported cotton fiber quality quantitative trait loci (QTLs) and the favorable allele types of GhCOBL9 Dt had significantly positive correlations with fiber quality traits, indicating that these two genes might play an important role in fiber development.
类COBRA（COBL）基因编码一种植物特有的糖基磷脂酰肌醇（GPI）锚定蛋白，已被证明是细胞扩张方向和纤维素结晶度状态的关键调节因子。已在拟南芥、水稻、玉米和番茄中进行了全基因组分析，但在棉花中研究较少。在这里，我们分别从三个已测序的棉花物种，即二倍体棉花雷蒙德氏棉、亚洲棉和四倍体棉花陆地棉TM-1中鉴定出19个、18个和33个候选COBL基因。这些COBL成员定位于雷蒙德氏棉的10条染色体上，可分为两个亚组。COBL基因的表达模式在陆地棉TM-1中表现出高度的发育和空间调控。其中，GhCOBL9和GhCOBL13在纤维发育的次生细胞壁阶段优先表达，并且与纤维素合酶基因GhCESA4、GhCESA7和GhCESA8有显著的共上调表达。此外，GhCOBL9 Dt和GhCOBL13 Dt与先前报道的棉花纤维品质数量性状位点（QTL）共定位，并且GhCOBL9 Dt的有利等位基因类型与纤维品质性状有显著正相关，表明这两个基因可能在纤维发育中起重要作用。
