Successful plant colonization by parasites requires the circumvention of host defenses, and sometimes a reprogramming of host metabolism, mediated by effector molecules delivered into the host. Using transcriptomic and enzymatic approaches, we characterized salivary glands and saliva of Phloeomyzus passerinii, an aphid exhibiting an atypical feeding strategy. Plant responses to salivary extracts of P. passerinii and Myzus persicae were assessed with poplar protoplasts of a susceptible and a resistant genotype, and in a heterologous Arabidopsis system. We predict that P. passerinii secretes a highly peculiar saliva containing effectors potentially interfering with host defenses, biotic stress signaling and plant metabolism, notably phosphatidylinositol phosphate kinases which seemed specific to P. passerinii. Gene expression profiles indicated that salivary extracts of M. persicae markedly affected host defenses and biotic stress signaling, while salivary extracts of P. passerinii induced only weak responses. The effector-triggered susceptibility was characterized by downregulations of genes involved in cytokinin signaling and auxin homeostasis. This suggests that P. passerinii induces an intracellular accumulation of auxin in susceptible host genotypes, which is supported by histochemical assays in Arabidopsis. This might in turn affect biotic stress signaling and contribute to host tissue manipulation by the aphid.

中文翻译：

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Phloeomyzus passerinii 的唾液蛋白，一种操纵植物的蚜虫，及其对易感和抗性杨树基因型早期基因反应的影响

寄生虫成功的植物定植需要绕过宿主防御，有时还需要重新编程宿主代谢，由传递到宿主的效应分子介导。使用转录组学和酶学方法，我们表征了 Phloeomyzus passerinii 的唾液腺和唾液，这是一种表现出非典型摄食策略的蚜虫。用易感和抗性基因型的杨树原生质体和异源拟南芥系统评估了植物对 P. passerinii 和桃蚜唾液提取物的反应。我们预测 P. passerinii 分泌一种高度奇特的唾液，其中含有可能干扰宿主防御、生物胁迫信号传导和植物代谢的效应物，尤其是 P. passerinii 特有的磷脂酰肌醇磷酸激酶。基因表达谱表明桃蚜的唾液提取物显着影响宿主防御和生物应激信号传导，而帕氏酵母的唾液提取物仅诱导微弱的反应。效应器触发的易感性的特点是参与细胞分裂素信号传导和生长素稳态的基因下调。这表明 P. passerinii 在易感宿主基因型中诱导细胞内生长素的积累，拟南芥中的组织化学分析支持了这一点。这可能反过来影响生物胁迫信号并有助于蚜虫对宿主组织的操纵。效应器触发的易感性的特点是参与细胞分裂素信号传导和生长素稳态的基因下调。这表明 P. passerinii 在易感宿主基因型中诱导细胞内生长素的积累，拟南芥中的组织化学分析支持了这一点。这可能反过来影响生物胁迫信号并有助于蚜虫对宿主组织的操纵。效应器触发的易感性的特点是参与细胞分裂素信号传导和生长素稳态的基因下调。这表明 P. passerinii 在易感宿主基因型中诱导细胞内生长素的积累，拟南芥中的组织化学分析支持了这一点。这可能反过来影响生物胁迫信号并有助于蚜虫对宿主组织的操纵。