Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil.
Braz J Med Biol Res. 2012 Feb;45(2):118-24. doi: 10.1590/s0100-879x2012007500008. Epub 2012 Jan 26.
Seed coat is a specialized maternal tissue that interfaces the embryo and the external environment during embryogenesis, dormancy and germination. In addition, it is the first defensive barrier against penetration by pathogens and herbivores. Here we show that Albizia lebbeck seed coat dramatically compromises the oviposition, eclosion and development of the bruchid Callosobruchus maculatus. Dietary supplementation of bruchid larvae with A. lebbeck seed coat flour causes severe weight loss and reduces survival. By means of protein purification, mass spectrometry and bioinformatic analyses, we show that chitin-binding vicilins are the main source of A. lebbeck tegumental toxicity to C. maculatus. At concentrations as low as 0.1%, A. lebbeck vicilins reduce larval mass from 8.1 ± 1.7 (mass of control larvae) to 1.8 ± 0.5 mg, which corresponds to a decrease of 78%. Seed coat toxicity constitutes an efficient defense mechanism, hindering insect predation and preventing embryo damage. We hypothesize that A. lebbeck vicilins are good candidates for the genetic transformation of crop legumes to enhance resistance to bruchid predation.
种皮是一种特化的母体组织，在胚胎发生、休眠和萌发期间与胚胎和外部环境相互作用。此外，它是抵御病原体和草食性动物侵袭的第一道防御屏障。在这里，我们发现相思树种皮严重影响了豆象 Callosobruchus maculatus 的产卵、孵化和发育。用相思树种皮粉饲养豆象幼虫会导致严重的体重减轻和存活率降低。通过蛋白质纯化、质谱分析和生物信息学分析，我们表明，几丁质结合的 vicilins 是相思树种皮对 C. maculatus 毒性的主要来源。在低至 0.1%的浓度下，相思树 vicilins 将幼虫的质量从 8.1 ± 1.7（对照幼虫的质量）降低到 1.8 ± 0.5 mg，降幅达 78%。种皮毒性构成了一种有效的防御机制，阻碍了昆虫的捕食，并防止了胚胎的损伤。我们假设相思树 vicilins 是遗传转化作物豆科植物以增强对豆象捕食抗性的良好候选物。
