Cotton Defense Induction Patterns Under Spatially, Temporally and Quantitatively Varying Herbivory Levels
Cotton Defense Induction Patterns Under Spatially, Temporally and Quantitatively Varying Herbivory Levels
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DOI：
10.3389/fpls.2017.00234
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发表时间：
2017-02-21
影响因子：
5.6
通讯作者：
Romeis, Jorg
中科院分区：
文献类型：
--
作者：
Eisenring, Michael;Meissle, Michael;Romeis, Jorg
棉花（Gossypium sp.）在抵御食草动物的过程中，部分依赖于一组可诱导的、不挥发的萜类化合物的产生。在相同的伤害水平下，诱导型棉花萜类化合物在植物最年轻叶片中的分配最高，这支持了最优防御理论（ODT）的假设，该理论预测植物根据其价值和食草动物攻击的可能性向组织分配防御化合物。然而，我们的知识是有限的，如何变化，因此更现实，损害水平可能会影响棉花防御组织。我们假设，即使植物受到时间、空间和数量变化的毛虫（Heliothis virescens）损害，叶片中萜类化合物的分配和萜类化合物储存腺体的密度也与ODT的假设一致。正如预期的那样，棉花植株将大部分防御分配给最年轻的叶片，而不管受损位置如何。而老叶的防御诱导则随损伤部位的不同而不同。在损伤处理结束后至少14天内，植物将防御资源从以前的嫩叶重新分配给新发育的叶片。此外，我们观察到叶片损伤面积与萜类化合物浓度和腺体密度之间存在正双曲线关系，表明棉花植株可以微调防御分配。虽然血管约束和单个防御化合物的化学性质等因素可能会影响防御水平，但我们的研究结果总体上表明，棉花在不同损伤处理下的诱导防御组织与ODT的关键假设一致。
In its defense against herbivores, cotton (Gossypium sp.) relies in part on the production of a set of inducible, non-volatile terpenoids. Under uniform damage levels, in planta allocation of induced cotton terpenoids has been found to be highest in youngest leaves, supporting assumptions of the optimal defense theory (ODT) which predicts that plants allocate defense compounds to tissues depending on their value and the likelihood of herbivore attack. However, our knowledge is limited on how varying, and thus more realistic, damage levels might affect cotton defense organization. We hypothesized that the allocation of terpenoids and densities of terpenoid-storing glands in leaves aligns with assumptions of the ODT, even when plants are subjected to temporally, spatially and quantitatively varying caterpillar (Heliothis virescens) damage. As expected, cotton plants allocated most of their defenses to their youngest leaves regardless of damage location. However, defense induction in older leaves varied with damage location. For at least 14 days after damage treatments ended, plants reallocated defense resources from previously young leaves to newly developed leaves. Furthermore, we observed a positive hyperbolic relationship between leaf damage area and both terpenoid concentrations and gland densities, indicating that cotton plants can fine-tune defense allocation. Although it appears that factors like vascular constraints and chemical properties of individual defense compounds can affect defense levels, our results overall demonstrate that induced defense organization of cotton subjected to varying damage treatments is in alignment with key assumptions of the ODT.