A unique latex protein, MLX56, defends mulberry trees from insects
A unique latex protein, MLX56, defends mulberry trees from insects
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DOI：
10.1016/j.phytochem.2009.04.014
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发表时间：
2009-05-01
期刊：
影响因子：
3.8
通讯作者：
Tateishi, Ken
中科院分区：
文献类型：
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作者：
Wasano, Naoya;Konno, Kotaro;Tateishi, Ken
几千年来，桑蚕（Morris spp.）与家蚕（Bombyx mori）的关系一直是一种众所周知的植物-草食相互作用。最近，我们发现桑叶是通过乳胶成分来抵御虫食的。本文报道了桑树乳胶中一个56-kDa（394个氨基酸）的防御蛋白mulatexin (MLX56)，该蛋白具有一个扩展蛋白结构域、两个hevein样几丁质结合结构域和一个无活性的几丁质酶样结构域，使桑树具有较强的抗虫性。MLX56对鳞翅目幼虫（包括甘蓝粘虫和黑蚕）在0.01%的浓度下有毒性，表明MLX56可用于植物保护。MLX56具有很强的蛋白酶消化抗性，并具有较强的几丁质结合活性。有趣的是，MLX56对家蚕B. mori没有毒性，这表明该桑树专家已经对桑树防御产生了适应。我们的研究结果表明，植物乳胶中的防御蛋白在桑树与昆虫的相互作用中起着关键作用，也可能在其他植物与昆虫的相互作用中起着关键作用。我们的研究结果进一步表明，类似于动物毒液的植物乳胶含有大量适用的防御蛋白和化学物质，这些蛋白质和化学物质是通过种间相互作用进化而来的。2009爱思唯尔有限公司版权所有。
The mulberry (Morris spp.)-silkworm (Bombyx mori) relationship has been a well-known plant-herbivore interaction for thousands of years. Recently, we found that mulberry leaves defend against insect herbivory by latex ingredients. Here we report that a 56-kDa (394 amino acid) defense protein in mulberry latex designated mulatexin (MLX56) with an extensin domain, two hevein-like chitin-binding domains, and an inactive chitinase-like domain provides mulberry trees with strong insect resistance. MLX56 is toxic to lepidopteran caterpillars, including the cabbage armyworm, Mamestra brassicae and the Eri silkworm, Samia ricini, at 0.01% concentration in a wet diet, suggesting that MLX56 is applicable for plant protection. MLX56 is highly resistant to protease digestion, and has a strong chitin-binding activity. Interestingly, MLX56 showed no toxicity to B. mori, suggesting that the mulberry specialist has developed adaptation to the mulberry defense. Our results show that defensive proteins in plant latex play key roles in mulberry-insect interactions, and probably also in other plant-insect interactions. Our results further suggest that plant latexes analogous to animal venom contain a treasury of applicable defense proteins and chemicals that has evolved through inter-specific interactions. (C) 2009 Elsevier Ltd. All rights reserved.