背景:豆类利用长距离信号反馈途径,称为结瘤自动调节(AON),调节它们与根瘤菌共生的建立和维持。已经发现了这种途径的几种关键蛋白质,但AON途径尚未完全了解。
结果:我们报告了一种新的超结瘤突变体,自动调节有缺陷,随着基因的破坏,DAR(Medtr2g450550/MtrunA17_Chr2g0304631),以前不知道在AON中发挥作用。dar-1突变体产生的结节比野生型多十倍,与具有破坏的SUNN基因功能的AON突变体相似。就像在sunn突变体中一样,在dar中,CLE肽MtCLE12和MtCLE13对结瘤的抑制被废除。此外,dar-1还显示丛枝菌根真菌的根长定植增加,提示DAR在菌根共生(AOM)的自动调节中的作用。然而,与SUNN在拍摄中控制结瘤的功能不同,根中的DAR函数。
结论:DAR编码一种膜蛋白,该蛋白是截尾支原体中一个小蛋白家族的成员。我们的结果表明,DAR可能参与参与共生调节的信号的亚细胞运输,但在共生过程中并没有上调。DAR基因家族成员也存在于拟南芥中,lycophytes,苔藓,和微藻,表明AON和AOM可能使用其他植物常见的途径成分,即使是那些没有经历共生的人。
BACKGROUND: Legumes utilize a long-distance signaling feedback pathway, termed Autoregulation of Nodulation (AON), to regulate the establishment and maintenance of their symbiosis with rhizobia. Several proteins key to this pathway have been discovered, but the AON pathway is not completely understood.
RESULTS: We report a new hypernodulating mutant, defective in autoregulation, with disruption of a gene, DAR (Medtr2g450550/MtrunA17_Chr2g0304631), previously unknown to play a role in AON. The dar-1 mutant produces ten-fold more nodules than wild type, similar to AON mutants with disrupted SUNN gene function. As in sunn mutants, suppression of nodulation by CLE peptides MtCLE12 and MtCLE13 is abolished in dar. Furthermore, dar-1 also shows increased root length colonization by an arbuscular mycorrhizal fungus, suggesting a role for DAR in autoregulation of mycorrhizal symbiosis (AOM). However, unlike SUNN which functions in the shoot to control nodulation, DAR functions in the root.
CONCLUSIONS: DAR encodes a membrane protein that is a member of a small protein family in M. truncatula. Our results suggest that DAR could be involved in the subcellular transport of signals involved in symbiosis regulation, but it is not upregulated during symbiosis. DAR gene family members are also present in Arabidopsis, lycophytes, mosses, and microalgae, suggesting the AON and AOM may use pathway components common to other plants, even those that do not undergo either symbiosis.