As a unique sulfated polysaccharide, fucoidan is an important component of cell wall in brown seaweeds. Its biochemical properties are determined by the positions and quantity of sulfate groups. Sulfotransferases (STs) catalyze the sulfation process, which transfer the sulfuryl groups to carbohydrate backbones and are crucial for fucoidan biosynthesis. Nevertheless, the structures and functions of STs in brown seaweeds are rarely investigated. There are a total of 44 ST genes identified from our genome and transcriptome analysis of Saccharina japonica, which were located in the 17 scaffolds and 11 contigs. The S. japonica ST genes have abundant introns and alternative splicing sites, and five tandem duplicated gene clusters were identified. Generally, the ST genes could be classified into five groups (Group I ~ V) based on phylogenetic analysis. Accordingly, the ST proteins, which were encoded by genes within the same group, contained similar conserved motifs. Members of the S. japonica ST gene family show various expression patterns in different tissues and developmental stages. Transcriptional profiles indicate that the transcriptional levels of more than half of the ST genes are higher in kelp basal blades than in distal blades. Except for ST5 and ST28, most ST genes are down-regulated with the kelp development stages. The expression levels of nine ST genes were detected by real-time quantitative PCR, which demonstrates that they responded to low salinity and drought stresses. Various characteristics of the STs allow the feasibilities of S. japonica to synthesize fucoidans with different sulfate groups. This enables the kelp the potential to adapt to the costal environments and meet the needs of S. japonica growth.

中文翻译：

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对整个发育时期和非生物胁迫下的糖精磺基转移酶基因及其转录谱进行全基因组分析。


岩藻依聚糖作为一种独特的硫酸化多糖，是褐藻细胞壁的重要组成部分。其生化性质由硫酸基的位置和数量决定。磺基转移酶 (ST) 催化硫酸化过程，将硫酰基转移到碳水化合物主链上，这对于岩藻依聚糖的生物合成至关重要。然而，褐海藻中 ST 的结构和功能却很少被研究。从我们对日本糖精的基因组和转录组分析中总共鉴定出 44 个 ST 基因，它们位于 17 个支架和 11 个重叠群中。粳稻ST基因具有丰富的内含子和可变剪接位点，并鉴定出5个串联重复基因簇。一般来说，基于系统发育分析，ST基因可分为五类（Group I~V）。因此，由同一组内的基因编码的ST蛋白包含相似的保守基序。 S. japonica ST基因家族的成员在不同组织和发育阶段表现出不同的表达模式。转录谱表明，海带基部叶片中超过一半的 ST 基因的转录水平高于远端叶片。除ST5和ST28外，大多数ST基因随海带发育阶段下调。通过实时定量PCR检测了9个ST基因的表达水平，表明它们对低盐和干旱胁迫有响应。 ST的各种特性使得日本海藻具有合成具有不同硫酸基团的岩藻依聚糖的可行性。这使得海带具有适应沿海环境并满足海带生长需求的潜力。