Involvement of autoregulation in the interaction between rhizobial nodulation and AM fungal colonization in soybean roots
Involvement of autoregulation in the interaction between rhizobial nodulation and AM fungal colonization in soybean roots
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DOI：
10.1007/s00374-013-0804-8
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发表时间：
2013
影响因子：
6.5
通讯作者：
K. Sakamoto;Natsuko Ogiwara;Tomomitsu Kaji
中科院分区：
文献类型：
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作者：
K. Sakamoto;Natsuko Ogiwara;Tomomitsu Kaji
大豆植株自我调节以抑制过度结瘤。最近发现，各种豆科植物的自我调节同时控制结瘤和丛枝菌根(AM)真菌的定植。我们研究了根瘤菌结瘤和AM真菌定植之间的相互作用中的自我调节。我们用的是野生型大豆。Enrei及其超结瘤突变体Kanto100，在自动调节方面存在缺陷。共设4个不同的处理：不接种对照、单独接种根瘤菌、单独接种AM真菌巨孢菌、根瘤菌和AM真菌混合接种。在Enrei和Kanto100中，AM真菌侵染都提高了根瘤的重量和固氮能力，表明AM真菌侵染对根瘤菌结瘤的促进作用与寄主植物的自身调节无关。在单独含有AM真菌的植物中，Enrei的AM真菌定殖率与Kanto100相当。然而，在双重接种的植物中，这一比例显著低于关东100(P<； 0.05)。为了证实寄主植物的自动调控对AM真菌定殖的控制，在Enrei和Kanto100之间进行了相互嫁接实验。在只含有AM真菌的植物中，AM真菌在Enrei(地上部)/Enrei(根)、Enrei/Kanto100、Kanto100/Enrei和Kanto100/Kanto100嫁接中的定殖率相当。然而，在双重接种的植株中，Enrei/Enrei和Enrei/Kanto100嫁接的AM真菌定殖率显著低于Kanto100/Enrei和Kanto100/Kanto100嫁接(P<； 0.05)。这些结果表明，根瘤菌的结瘤抑制了AM真菌的定植，而由根瘤引起的寄主植物的自我调节参与了这一现象。
Soybean plants autoregulate to suppress excessive nodulation. It has been revealed recently that the autoregulation of various legumes controls both nodulation and arbuscular mycorrhizal (AM) fungal colonization. We investigated the involvement of autoregulation in the interaction between rhizobial nodulation and AM fungal colonization. We used a wild-type soybean cv. Enrei and its hypernodulating mutant Kanto100, defective in the autoregulation. We included four different treatments: an uninoculated control, inoculation with rhizobiumBradyrhizobium japonicumalone, inoculation with AM fungusGigaspora roseaalone, and dual inoculation with rhizobium and AM fungus. In both Enrei and Kanto100, AM fungal colonization enhanced the weight and N2fixation of nodules, suggesting that autoregulation of host plant is not involved in the stimulatory effect of AM fungal colonization on rhizobial nodulation. In plants with the AM fungus alone, the AM fungal colonization of Enrei was comparable to that of Kanto100. In plants with dual inoculation, however, this was significantly (P< 0.05) lower than in Kanto100. To confirm the control of AM fungal colonization by the autoregulation of host plant, a reciprocal grafting experiment was performed between Enrei and Kanto100. In plants with the AM fungus alone, AM fungal colonization was comparable among Enrei (shoot)/Enrei (root), Enrei/Kanto100, Kanto100/Enrei, and Kanto100/Kanto100 grafts. In plants with dual inoculation, however, AM fungal colonization of Enrei/Enrei and Enrei/Kanto100 grafts was significantly (P< 0.05) lower than that of Kanto100/Enrei and Kanto100/Kanto100. These results indicate that rhizobial nodulation suppresses AM fungal colonization, and the autoregulation of host plant, initiated by nodulation, is involved in this phenomenon.