Gutjahr Caroline, Siegler Heike, Haga Ken, Iino Moritoshi, Paszkowski Uta
Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne, Switzerland; Institute of Genetics, University of Munich (LMU), Biocenter Martinsried, Martinsried, Germany.
Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne, Switzerland.
PLoS One. 2015 Apr 10;10(4):e0123422. doi: 10.1371/journal.pone.0123422. eCollection 2015.
Development of the mutualistic arbuscular mycorrhiza (AM) symbiosis between most land plants and fungi of the Glomeromycota is regulated by phytohormones. The role of jasmonate (JA) in AM colonization has been investigated in the dicotyledons Medicago truncatula, tomato and Nicotiana attenuata and contradicting results have been obtained with respect to a neutral, promotive or inhibitory effect of JA on AM colonization. Furthermore, it is currently unknown whether JA plays a role in AM colonization of monocotyledonous roots. Therefore we examined whether JA biosynthesis is required for AM colonization of the monocot rice. To this end we employed the rice mutant constitutive photomorphogenesis 2 (cpm2), which is deficient in JA biosynthesis. Through a time course experiment the amount and morphology of fungal colonization did not differ between wild-type and cpm2 roots. Furthermore, no significant difference in the expression of AM marker genes was detected between wild type and cpm2. However, treatment of wild-type roots with 50 μM JA lead to a decrease of AM colonization and this was correlated with induction of the defense gene PR4. These results indicate that JA is not required for AM colonization of rice but high levels of JA in the roots suppress AM development likely through the induction of defense.
大多数陆地植物与球囊菌门真菌之间互利共生的丛枝菌根（AM）共生关系的发展受植物激素调控。茉莉酸（JA）在AM定殖中的作用已在双子叶植物蒺藜苜蓿、番茄和渐狭叶烟草中进行了研究，关于JA对AM定殖的中性、促进或抑制作用，得到了相互矛盾的结果。此外，目前尚不清楚JA在单子叶植物根的AM定殖中是否起作用。因此，我们研究了单子叶植物水稻的AM定殖是否需要JA生物合成。为此，我们使用了JA生物合成缺陷的水稻突变体组成型光形态建成2（cpm2）。通过时间进程实验，野生型和cpm2根之间真菌定殖的数量和形态没有差异。此外，野生型和cpm2之间未检测到AM标记基因表达的显著差异。然而，用50μM JA处理野生型根会导致AM定殖减少，这与防御基因PR4的诱导相关。这些结果表明，水稻的AM定殖不需要JA，但根中高水平的JA可能通过诱导防御来抑制AM发育。
