An Aphid-Secreted Salivary Protease Activates Plant Defense in Phloem
An Aphid-Secreted Salivary Protease Activates Plant Defense in Phloem
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蚜虫分泌的唾液蛋白酶激活韧皮部的植物防御
DOI：
10.1016/j.cub.2020.09.020
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发表时间：
2020-12-21
期刊：
影响因子：
9.2
通讯作者：
Sun, Yucheng
中科院分区：
文献类型：
--
作者：
Guo, Huijuan;Zhang, Yanjing;Sun, Yucheng
最近的研究报道，蚜虫在最初的探测和摄食过程中通过分泌唾液蛋白进入寄主组织来促进它们在寄主植物中的定植。其中一些唾液蛋白引发植物防御，但在韧皮部局部抗性激活的分子和生化机制仍然知之甚少。桃蚜（Myzus persicae）是一种广义的韧皮部吸吮害虫，包含许多与特定寄主植物物种相关并适应的谱系。目前的研究发现，与烟草适应的蚜虫谱系相比，来自非烟草适应（NTA）蚜虫谱系的唾液腺和唾液中的半胱氨酸蛋白酶组织蛋白酶B3 （CathB3）及其相关基因CathB3上调。此外，敲低CathB3可改善NTA系对烟草的处理性能，并且发现CathB3的前肽结构域与烟草细胞质激酶EDR1-like结合，从而引发烟草韧皮部活性氧的积累，从而抑制NTA系对韧皮部的摄食和定植。这些发现揭示了蚜虫唾液中组织蛋白酶型蛋白酶的一种新功能，该功能可引发有效的寄主植物防御，并为多面手蚜虫的寄主特化理论提供了依据。
Recent studies have reported that aphids facilitate their colonization of host plants by secreting salivary proteins into host tissues during their initial probing and feeding. Some of these salivary proteins elicit plant defenses, but the molecular and biochemical mechanisms that underlie the activation of phloemlocalized resistance remain poorly understood. The aphid Myzus persicae, which is a generalized phloem-sucking pest, encompasses a number of lineages that are associated with and adapted to specific host plant species. The current study found that a cysteine protease Cathepsin B3 (CathB3), and the associated gene CathB3, was upregulated in the salivary glands and saliva of aphids from a non-tobaccoadapted (NTA) aphid lineage, when compared to those of a tobacco-adapted lineage. Furthermore, the knockdown of CathB3 improved the performance of NTA lineages on tobacco, and the propeptide domain of CathB3 was found to bind to tobacco cytoplasmic kinase ENHANCED DISEASE RESISTANCE 1-like (EDR1-like), which triggers the accumulation of reactive oxygen species in tobacco phloem, thereby suppressing both phloem feeding and colonization by NTA lineages. These findings reveal a novel function for a cathepsin-type protease in aphid saliva that elicits effective host plant defenses and warranted the theory of host specialization for generalist aphids.