Abstract：
The synthesis of cell-wall sulfated galactans proceeds through UDP galactose, a major nucleotide sugar in red seaweed, whilst sulfate is transported through S-transporters into algae. Moreover, synthesis of ethylene, a volatile plant growth regulator that plays an important role in red seaweed reproduction, occurs through S-adenosyl methionine. This means that sulfur metabolism is involved in reproduction events as well as sulfated galactan synthesis of red seaweed. In this work we study the effects of methionine and MgSO4 on gene expression of polygalactan synthesis through phosphoglucomutase (PGM) and galactose 1 phosphate uridyltransferase (GALT) and of sulfate assimilation (S-transporter and sulfate adenylyltransferase, SAT) using treatment of ethylene for 15 min, which elicited cystocarp development in Grateloupia imbricata. Also, expressions of carbohydrate sulfotransferase and galactose-6-sulfurylase in charge of the addition and removal of sulfate groups to galactans backbone were examined. Outstanding results occurred in the presence of methionine, which provoked an increment in transcript number of genes encoding S-transporter and assimilation compared to controls regardless of the development stage of thalli. Otherwise, methionine diminished the transcript levels of PGM and GALT and expressions are associated with the fertilization stage of thalli of G. imbricata. As opposite, methionine and MgSO4 did not affect the transcript number of carbohydrate sulfotransferase and galactose-6-sulfurylase. Nonetheless, differential expression was obtained for sulfurylases according to the development stages of thalli of G. imbricata.
摘要：
细胞壁硫酸化半乳聚糖的合成通过UDP半乳糖进行，红藻中的一种主要核苷酸糖，而硫酸盐通过S-转运蛋白转运到藻类中。此外，乙烯的合成，一种挥发性植物生长调节剂，在红藻繁殖中起着重要作用，通过S-腺苷蛋氨酸发生。这意味着硫代谢涉及繁殖事件以及红藻的硫酸化半乳聚糖合成。在这项工作中，我们研究了蛋氨酸和MgSO4对通过磷酸葡萄糖变位酶（PGM）和半乳糖1磷酸尿酰转移酶（GALT）和硫酸盐同化（S-转运体和硫酸盐腺酰基转移酶，SAT)使用乙烯处理15分钟，这引起了根皮草的球果发育。此外，检查了碳水化合物磺基转移酶和半乳糖-6-硫酸化酶在半乳聚糖骨架上添加和去除硫酸基团的表达。出色的结果发生在蛋氨酸的存在，与对照组相比，无论thalli的发育阶段如何，都会引起编码S转运蛋白和同化的基因的转录本数量增加。否则,甲硫氨酸降低了PGM和GALT的转录水平，并且表达与隐球菌的thalli的受精阶段有关。相反，蛋氨酸和MgSO4不影响碳水化合物磺基转移酶和半乳糖-6-硫酸化酶的转录数。尽管如此，根据G.imbricatathalli的发育阶段，获得了硫基转移酶的差异表达。
