Incremental steps toward incompatibility revealed by Arabidopsis epistatic interactions modulating salicylic acid pathway activation
Incremental steps toward incompatibility revealed by Arabidopsis epistatic interactions modulating salicylic acid pathway activation
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DOI：
10.1073/pnas.0811734106
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发表时间：
2009-01-06
影响因子：
11.1
通讯作者：
Reymond, Matthieu
中科院分区：
文献类型：
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作者：
Alcazar, Ruben;Garcia, Ana V.;Reymond, Matthieu
植物生长受遗传因素和环境因素的影响。基因型与环境的相互作用是由复杂的遗传上位网络控制的，这些网络受到自然选择的影响。在这里，我们描述了一种新的上位相互作用调节生长响应温度共同的2拟南芥重组自交系（RIL）人口（Ler x卡斯-2和Ler x Kond）。在14 ℃时，在相互作用位点（不相容相互作用）具有特定等位基因组合的品系具有严重的生长缺陷。这些品系表现出失调的细胞死亡程序和增强的抗病性。在20摄氏度，生长缺陷被抑制，但增强的抗性的积极特征被保留。1相互作用的QTL定位到3号染色体上的RPP 1-like TIR-NB-LRR基因簇与我们的发现一致，即环境条件上位性依赖于水杨酸（SA）应激信号通路的激活。上位性互作的性质符合Dobzhansky-Muller生殖隔离的遗传不亲和性与不完全互作模型。不同不亲和系的适应性变化揭示了遗传背景中存在额外的修饰符。我们建议，某些相互作用的位点导致生长和抵抗病原体之间的最佳平衡，通过调节SA信号在特定的环境下。在达到完全生殖隔离之前，这可能会积累更多的不相容性。
Plant growth is influenced by genetic factors and environmental cues. Genotype-by-environment interactions are governed by complex genetic epistatic networks that are subject to natural selection. Here we describe a novel epistatic interaction modulating growth in response to temperature common to 2 Arabidopsis recombinant inbred line (RIL) populations (Ler x Kas-2 and Ler x Kond). At 14 degrees C, lines with specific allele combinations at interacting loci (incompatible interactions) have severe growth defects. These lines exhibit deregulated cell death programs and enhanced disease resistance. At 20 degrees C, growth defects are suppressed, but a positive trait of enhanced resistance is retained. Mapping of 1 interacting QTL to a cluster of RPP1-like TIR-NB-LRR genes on chromosome 3 is consistent with our finding that environmentally conditioned epistasis depends on activation of the salicylic acid (SA) stress signaling pathway. The nature of the epistatic interaction conforms to the Dobzhansky-Muller model of genetic incompatibility with incomplete penetrance for reproductive isolation. Variation in fitness of different incompatible lines reveals the presence of additional modifiers in the genetic background. We propose that certain interacting loci lead to an optimal balance between growth and resistance to pathogens by modulating SA signaling under specific environments. This could allow the accumulation of additional incompatibilities before reaching complete reproductive isolation.