Vetter Madlen, Karasov Talia L, Bergelson Joy
Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America.
Committee on Genetics, Genomics and Systems Biology, University of Chicago, Chicago, Illinois, United States of America.
PLoS Genet. 2016 Jun 23;12(6):e1006068. doi: 10.1371/journal.pgen.1006068. eCollection 2016 Jun.
A first line of defense against pathogen attack for both plants and animals involves the detection of microbe-associated molecular patterns (MAMPs), followed by the induction of a complex immune response. Plants, like animals, encode several receptors that recognize different MAMPs. While these receptors are thought to function largely redundantly, the physiological responses to different MAMPs can differ in detail. Responses to MAMP exposure evolve quantitatively in natural populations of Arabidopsis thaliana, perhaps in response to environment specific differences in microbial threat. Here, we sought to determine the extent to which the detection of two canonical MAMPs were evolving redundantly or distinctly within natural populations. Our results reveal negligible correlation in plant growth responses between the bacterial MAMPs EF-Tu and flagellin. Further investigation of the genetic bases of differences in seedling growth inhibition and validation of 11 candidate genes reveal substantial differences in the genetic loci that underlie variation in response to these two MAMPs. Our results indicate that natural variation in MAMP recognition is largely MAMP-specific, indicating an ability to differentially tailor responses to EF-Tu and flagellin in A. thaliana populations.
植物和动物抵御病原体攻击的第一道防线都涉及对微生物相关分子模式（MAMPs）的检测，随后引发复杂的免疫反应。与动物一样，植物编码了几种识别不同MAMPs的受体。虽然这些受体在很大程度上被认为功能冗余，但对不同MAMPs的生理反应在细节上可能有所不同。在拟南芥的自然种群中，对MAMP暴露的反应在数量上有所进化，这可能是对微生物威胁中特定环境差异的反应。在这里，我们试图确定在自然种群中，对两种典型MAMPs的检测在多大程度上是冗余进化还是独立进化的。我们的结果显示，细菌MAMPs EF-Tu和鞭毛蛋白之间的植物生长反应相关性可忽略不计。对幼苗生长抑制差异的遗传基础的进一步研究以及对11个候选基因的验证揭示了对这两种MAMPs反应差异背后的基因座存在实质性差异。我们的结果表明，MAMP识别中的自然变异在很大程度上是MAMP特异性的，这表明拟南芥种群有能力对EF-Tu和鞭毛蛋白做出不同的反应调整。
