Arbuscular mycorrhizal symbiosis is accompanied by local and systemic alterations in gene expression and an increase in disease resistance in the shoots
Arbuscular mycorrhizal symbiosis is accompanied by local and systemic alterations in gene expression and an increase in disease resistance in the shoots
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DOI：
10.1111/j.1365-313x.2007.03069.x
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发表时间：
2007-05-01
期刊：
影响因子：
7.2
通讯作者：
Harrison, Maria J.
中科院分区：
文献类型：
--
作者：
Liu, Jinyuan;Maldonado-Mendoza, Ignacio;Harrison, Maria J.
在自然生态系统中，许多植物的根部与丛枝菌根（AM）真菌共存，由此产生的共生关系对植物产生深远的影响。最常见的反应是增加磷营养；然而，还注意到了其他影响，包括增强对非生物和生物胁迫的抵抗力。在这里，我们使用 16 000 个特征的寡核苷酸阵列和实时定量 RT-PCR 来探索 AM 共生在蒺藜苜蓿根和芽中引发的转录变化。通过控制实验条件，磷相关的影响被最小化，并且揭示了对 AM 真菌的局部和全身转录反应。根和芽的转录反应在基因诱导的程度和菌根调节基因的预测功能类别方面都不同。在根中，鉴定出了针对三种不同 AM 真菌进行调节的基因，并且通过分根实验，在菌根根系统的定植或非定植部分中发现了额外的一层调节。菌根植物芽的转录谱表明，许多预计参与应激或防御反应的基因被系统诱导，并表明菌根植物可能表现出增强的抗病性。实验证据支持这一预测，并且菌根蒺藜植物对剧毒细菌病原体野油菜黄单胞菌表现出更强的抵抗力。因此，共生伴随着基因表达的局部和全身变化的复杂模式，包括功能性防御反应的诱导。
In natural ecosystems, the roots of many plants exist in association with arbuscular mycorrhizal (AM) fungi, and the resulting symbiosis has profound effects on the plant. The most frequently documented response is an increase in phosphorus nutrition; however, other effects have been noted, including increased resistance to abiotic and biotic stresses. Here we used a 16 000-feature oligonucleotide array and real-time quantitative RT-PCR to explore transcriptional changes triggered in Medicago truncatula roots and shoots as a result of AM symbiosis. By controlling the experimental conditions, phosphorus-related effects were minimized, and both local and systemic transcriptional responses to the AM fungus were revealed. The transcriptional response of the roots and shoots differed in both the magnitude of gene induction and the predicted functional categories of the mycorrhiza-regulated genes. In the roots, genes regulated in response to three different AM fungi were identified, and, through split-root experiments, an additional layer of regulation, in the colonized or non-colonized sections of the mycorrhizal root system, was uncovered. Transcript profiles of the shoots of mycorrhizal plants indicated the systemic induction of many genes predicted to be involved in stress or defense responses, and suggested that mycorrhizal plants might display enhanced disease resistance. Experimental evidence supports this prediction, and mycorrhizal M. truncatula plants showed increased resistance to a virulent bacterial pathogen, Xanthomonas campestris. Thus, the symbiosis is accompanied by a complex pattern of local and systemic changes in gene expression, including the induction of a functional defense response.