North China Key Laboratory for Crop Germplasm Resources of Education Ministry, Agricultural University of Hebei, Baoding, China.
PLoS One. 2013 Jul 17;8(7):e70185. doi: 10.1371/journal.pone.0070185. Print 2013.
Fasciclin-like arabinogalactan (FLA) protein is a cell-wall-associated protein playing crucial roles in regulating plant growth and development, and it was characterized in different plants including Upland cotton (Gossypium hirsutum L.). In cDNA-AFLP analysis of 25 DPA (days post anthesis) fiber mRNA, two FLA gene-related transcripts exhibit differential expression between Sea Island cotton (G. barbadense L.) and Upland cotton. Based on the transcript-derived fragment, RACE-PCR and realtime PCR technique, GbFLA5 full-length cDNA was isolated and its expression profiles were characterized in both cotton plant tissues and secondary cell wall (SCW) fibers in this study. The 1154 bp GbFLA5 cDNA contains an ORF of 720 bp, encoding GbFLA5 protein of 239 amino acids residues in length with an estimated molecular mass of 25.41 kDa and isoelectric point of 8.63. The deduced GbFLA5 protein contains an N-terminal signal sequence, two AGP-like domains, a single fasciclin-like domain, and a GPI anchor signal sequence. Phylogenetic analysis shows that GbFLA5 protein is homologous to some known SCW-specific expressed FLAs of plant developing xylem, tension wood and cotton fibers. In the SCW deposition stage from 15 to 45 DPA detected, FLA5 maintains a significantly higher expression level in Sea Island cotton fibers than in Upland cotton fibers. The increasing FLA5 transcript abundance coincided with the SCW deposition process and the expression intensity differences coincided with their fiber strength differences between Sea Island cotton and Upland cotton. These expression profile features of GbFLA5 in cotton fibers revealed its tissue-specific and SCW developmental stage-specific expression characters. Further analysis suggested that GbFLA5 is a crucial SCW-specific protein which may contribute to fiber strength by affecting cellulose synthesis and microfibril deposition orientation.
纤维粘连蛋白样阿拉伯半乳聚糖蛋白（FLA）是一种与细胞壁相关的蛋白，在调控植物生长和发育过程中起着至关重要的作用，在不同植物中都有其特征，包括陆地棉（Gossypium hirsutum L.）。在对 25 天授粉后天数（DPA）纤维 mRNA 的 cDNA-AFLP 分析中，海岛棉（G. barbadense L.）和陆地棉之间有两个 FLA 基因相关转录本表现出差异表达。基于转录本衍生片段，本研究通过 RACE-PCR 和实时 PCR 技术分离得到 GbFLA5 的全长 cDNA，并对其在棉花组织和次生细胞壁（SCW）纤维中的表达谱进行了特征分析。GbFLA5 cDNA 全长 1154bp，包含一个 720bp 的开放阅读框，编码 239 个氨基酸残基的 GbFLA5 蛋白，预计分子量为 25.41 kDa，等电点为 8.63。推导的 GbFLA5 蛋白包含一个 N 端信号序列、两个 AGP 样结构域、一个单一的纤维粘连蛋白样结构域和一个 GPI 锚定信号序列。系统进化分析表明，GbFLA5 蛋白与一些已知的植物发育木质部、紧张木和棉纤维中 SCW 特异性表达的 FLAs 具有同源性。在从 15 到 45 DPA 的 SCW 沉积阶段检测到，FLA5 在海岛棉纤维中的表达水平明显高于陆地棉纤维。FLA5 转录本丰度的增加与 SCW 沉积过程相吻合，表达强度的差异与海岛棉和陆地棉纤维之间的纤维强度差异相吻合。GbFLA5 在棉花纤维中的这些表达谱特征揭示了其组织特异性和 SCW 发育阶段特异性表达特征。进一步分析表明，GbFLA5 是一种关键的 SCW 特异性蛋白，可能通过影响纤维素合成和微纤维沉积方向来促进纤维强度。
