The role of endogenous thiamine produced via THIC in root nodule symbiosis in Lotus japonicus
The role of endogenous thiamine produced via THIC in root nodule symbiosis in Lotus japonicus
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THIC产生的内源硫胺素在百脉根瘤共生中的作用
DOI：
10.1016/j.plantsci.2019.03.011
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发表时间：
2019-06-01
期刊：
影响因子：
5.2
通讯作者：
Chen, Yaping
中科院分区：
文献类型：
--
作者：
Yin, Yehu;Tian, Lu;Chen, Yaping
硫胺素是一种重要的初级代谢物，是所有生物不可缺少的。虽然硫胺素的生物合成途径已被充分记录，但其影响豆科植物与根瘤菌共生的机制仍不确定。本文通过过表达转基因植株、突变体和嫁接实验，探讨了硫胺素在日本莲结瘤中的作用。ljlic突变体表现出致死性表型，缺陷可以通过补充硫胺素或过表达ljlic来克服。野生型岐阜县B-129与石柳的互接表明，地上部分的光合产物对石柳克服结瘤缺陷起主要作用。过表达ljlic （e - ljlic）降低了日本莲苗的生长，提高了2-氧戊二酸脱氢酶和丙酮酸脱氢酶的活性。与野生型相比，e - ljthic植株侵染线数增加，结瘤数量增多，结瘤大小较小，但氮酶活性不变。综上所述，我们的研究结果表明，通过ljthh产生的内源硫胺素是寄主植物提供的根瘤菌感染和根瘤菌生长所必需的营养物质。
Thiamine is a pivotal primary metabolite which is indispensable to all organisms. Although its biosynthetic pathway has been well documented, the mechanism by which thiamine influences the legume-rhizobium symbiosis remains uncertain. Here, we used overexpressing transgenic plants, mutants and grafting experiments to investigate the roles played by thiamine in Lotus japonicus nodulation. ljthic mutants displayed lethal phenotypes and the defect could be overcome by supplementation of thiamine or by overexpression of LjTHIC. Reciprocal grafting between L. japonicus wild-type Gifu B-129 and ljthic showed that the photosynthetic products of the aerial part made a major contribution to overcoming the nodulation defect in ljthic. Overexpression of LjTHIC in Lotus japonicus (OE-LjTHIC) decreased shoot growth and increased the activity of the enzymes 2-oxoglutarate dehydrogenase and pyruvate dehydrogenase. OE-LjTHIC plants exhibited an increase in the number of infection threads and also developed more nodules, which were of smaller size but unchanged nitrogenase activity compared to the wildtype. Taken together, our results suggest that endogenous thiamine produced via LjTHIC acts as an essential nutrient provided by the host plant for rhizobial infection and nodule growth in the Lotus japonicus - rhizobium interaction.