The relationship between thiamine and two symbioses: Root nodule symbiosis and arbuscular mycorrhiza
The relationship between thiamine and two symbioses: Root nodule symbiosis and arbuscular mycorrhiza
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DOI：
10.1080/15592324.2016.1265723
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发表时间：
2016-12
影响因子：
2.9
通讯作者：
Miwa Nagae;M. Parniske;M. Kawaguchi;N. Takeda
中科院分区：
文献类型：
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作者：
Miwa Nagae;M. Parniske;M. Kawaguchi;N. Takeda
摘要：荷花THIC在所有器官中均有表达，其编码蛋白可催化硫胺素的生物合成。功能丧失会导致黄化，这是一种典型的硫胺素缺乏表型，并导致死亡。为了研究硫胺素在共生中的作用，我们重点研究了THI1，这是一种在根、根瘤和种子中表达的硫胺素生物合成基因。thi1突变体叶片为绿色，但形成小结节和未成熟种子。这些表型是由THI1互补和外源硫胺素拯救的。因此，THI1是结节扩大和种子成熟所必需的。另一方面，在thi1突变体中，丛枝菌根真菌（AM） Rhizophagus irregularis的定殖不受外源硫胺素的影响。然而，尽管缺乏硫胺素生物合成基因，但不规则孢子比寄主植物储存更多的硫胺素。因此，干扰硫胺素的供应会影响后代的表型，如孢子的形成和菌丝的生长。需要进一步的研究来阐明硫胺素对AM的影响。
ABSTRACT Lotus japonicus THIC is expressed in all organs, and the encoded protein catalyzes thiamine biosynthesis. Loss of function produces chlorosis, a typical thiamine-deficiency phenotype, and mortality. To investigate thiamine's role in symbiosis, we focused on THI1, a thiamine-biosynthesis gene expressed in roots, nodules, and seeds. The thi1 mutant had green leaves, but formed small nodules and immature seeds. These phenotypes were rescued by THI1 complementation and by exogenous thiamine. Thus, THI1 is required for nodule enlargement and seed maturation. On the other hand, colonization by arbuscular mycorrhiza (AM) fungus Rhizophagus irregularis was not affected in the thi1 mutant or by exogenous thiamine. However, spores of R. irregularis stored more thiamine than the source (host plants), despite lacking thiamine biosynthesis genes. Therefore, disturbance of the thiamine supply would affect progeny phenotypes such as spore formation and hyphal growth. Further investigation will be required to elucidate thiamine's effect on AM.