Nonuniform distribution of glucosinolates in Arabidopsis thaliana leaves has important consequences for plant defense
Nonuniform distribution of glucosinolates in Arabidopsis thaliana leaves has important consequences for plant defense
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DOI：
10.1073/pnas.0711730105
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发表时间：
2008-04-22
影响因子：
11.1
通讯作者：
Gershenzon, Jonathan
中科院分区：
文献类型：
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作者：
Shroff, Rohit;Vergara, Fredd;Gershenzon, Jonathan
植物防御在叶片内的空间分布可能是解释植食性模式的关键。通才的鳞翅目幼虫，棉铃虫（棉铃虫），避免了中脉和周边的拟南芥莲座叶，几乎只吃内层。这种进食模式归因于芥子油苷，因为它在缺乏通过水解激活芥子油苷防御能力的黑芥子酶突变体中并不明显。测定硫代葡萄糖苷在A.在精细尺度上，我们从MALDI-TOF（基质辅助激光解吸/电离-飞行时间）质谱构建了离子强度图。主要的硫代葡萄糖苷被发现是更丰富的组织的中脉和周边的叶片比内部叶片，模式，通过HPLC分析解剖叶验证。此外，三种主要硫代葡萄糖苷在不同叶区的比例也存在差异。因此，硫代葡萄糖苷在叶内的分布似乎控制了H.棉铃虫幼虫硫代葡萄糖苷的优先分配到外围可能发挥了关键作用，通过创建一个障碍，咀嚼食草动物，经常接近叶边缘的喂养防御。
The spatial distribution of plant defenses within a leaf may be critical in explaining patterns of herbivory. The generalist lepidopteran larvae, Helicoverpa armigera (the cotton bollworm), avoided the midvein and periphery of Arabidopsis thaliana rosette leaves and fed almost exclusively on the inner lamina. This feeding pattern was attributed to glucosinolates because it was not evident in a myrosinase mutant that lacks the ability to activate glucosinolate defenses by hydrolysis. To measure the spatial distribution of glucosinolates in A. thaliana leaves at a fine scale, we constructed ion intensity maps from MALDI-TOF (matrix assisted laser desorption/ionization-time of flight) mass spectra. The major glucosinolates were found to be more abundant in tissues of the midvein and the periphery of the leaf than the inner lamina, patterns that were validated by HPLC analyses of dissected leaves. In addition, there were differences in the proportions of the three major glucosinolates in different leaf regions. Hence, the distribution of glucosinolates within the leaf appears to control the feeding preference of H. armigera larvae. The preferential allocation of glucosinolates to the periphery may play a key role in the defense of leaves by creating a barrier to the feeding of chewing herbivores that frequently approach leaves from the edge.