The Eucalyptus Cuticular Waxes Contribute in Preformed Defense Against Austropuccinia psidii
The Eucalyptus Cuticular Waxes Contribute in Preformed Defense Against Austropuccinia psidii
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DOI：
10.3389/fpls.2018.01978
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发表时间：
2019-01-09
影响因子：
5.6
通讯作者：
Quecine, Maria Carolina
中科院分区：
文献类型：
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作者：
dos Santos, Isaneli Batista;Lopes, Mariana da Silva;Quecine, Maria Carolina
桃金娘锈病的病原桃金娘锈病是一种依赖寄主组织生长发育的生物营养性病原体。psidii的尿道孢子通过与寄主表面的密切接触和与叶角质层的相互作用感染桉树，并提供重要的化学和物理信号来触发感染过程。本研究对桉树（Eucalyptus spp.）表皮蜡质进行了分析，以确定其组成或结构及其与psidii易感/抗性的关系。21种桉树属被划分为抗性或易感。在控制条件下，利用qPCR技术验证了6种桉树的抗性/敏感性水平，发现病原菌可以在某些树种的桉树表面萌发，而不会在寄主体内繁殖。gc - tofms分析在桉树角质层中检测到26种化合物，发现了十六烷酸在巨桉和褐毛桉对psidii的敏感性中起作用。利用扫描电镜对6种桉树的表皮蜡形态进行了表征，并观察了寄主侵染过程中psidii萌发的不同行为。发现表皮形态与psidii抗性之间存在相关性。然而，在本研究中，我们首次报道了桉树对psidii的敏感性及其与表皮蜡化合物的相关性，这些化合物似乎作为一种预先形成的防御机制发挥协同作用。
Austropuccinia psidii, the causal agent of myrtle rust, is a biotrophic pathogen whose growth and development depends on the host tissues. The uredospores of A. psidii infect Eucalyptus by engaging in close contact with the host surface and interacting with the leaf cuticle that provides important chemical and physical signals to trigger the infection process. In this study, the cuticular waxes of Eucalyptus spp. were analyzed to determine their composition or structure and correlation with susceptibility/resistance to A. psidii. Twenty-one Eucalyptus spp. in the field were classified as resistant or susceptible. The resistance/susceptibility level of six Eucalyptus spp. were validated in controlled conditions using qPCR, revealing that the pathogen can germinate on the eucalyptus surface of some species without multiplying in the host. CG-TOFMS analysis detected 26 compounds in the Eucalyptus spp. cuticle and led to the discovery of the role of hexadecanoic acid in the susceptibility of Eucalyptus grandis and Eucalyptus phaeotricha to A. psidii. We characterized the epicuticular wax morphology of the six previously selected Eucalyptus spp. using scanning electron microscopy and observed different behavior in A. psidii germination during host infection. It was found a correlation of epicuticular morphology on the resistance to A. psidii. However, in this study, we provide the first report of considerable interspecific variation in Eucalyptus spp. on the susceptibility to A. psidii and its correlation with cuticular waxes chemical compounds that seem to play a synergistic role as a preformed defense mechanism.