Department of Horticulture and Landscape Architecture and Center for Rhizosphere Biology, Colorado State University, Fort Collins, CO 80523, USA.
BMC Plant Biol. 2010 Jun 17;10:115. doi: 10.1186/1471-2229-10-115.
Chemical and biological processes dictate an individual organism's ability to recognize and respond to other organisms. A small but growing body of evidence suggests that plants may be capable of recognizing and responding to neighboring plants in a species specific fashion. Here we tested whether or not individuals of the invasive exotic weed, Centaurea maculosa, would modulate their defensive strategy in response to different plant neighbors.
In the greenhouse, C. maculosa individuals were paired with either conspecific (C. maculosa) or heterospecific (Festuca idahoensis) plant neighbors and elicited with the plant defense signaling molecule methyl jasmonate to mimic insect herbivory. We found that elicited C. maculosa plants grown with conspecific neighbors exhibited increased levels of total phenolics, whereas those grown with heterospecific neighbors allocated more resources towards growth. To further investigate these results in the field, we conducted a metabolomics analysis to explore chemical differences between individuals of C. maculosa growing in naturally occurring conspecific and heterospecific field stands. Similar to the greenhouse results, C. maculosa individuals accumulated higher levels of defense-related secondary metabolites and lower levels of primary metabolites when growing in conspecific versus heterospecific field stands. Leaf herbivory was similar in both stand types; however, a separate field study positively correlated specialist herbivore load with higher densities of C. maculosa conspecifics.
Our results suggest that an individual C. maculosa plant can change its defensive strategy based on the identity of its plant neighbors. This is likely to have important consequences for individual and community success.
化学和生物过程决定了一个生物体识别和响应其他生物体的能力。越来越多的证据表明，植物可能具有识别和响应同种植物邻居的能力。在这里，我们测试了入侵外来杂草 Centaurea maculosa 的个体是否会根据不同的植物邻居来调节其防御策略。
在温室中，将 Centaurea maculosa 个体与同种（Centaurea maculosa）或异种（Festuca idahoensis）植物邻居配对，并使用植物防御信号分子茉莉酸甲酯（methyl jasmonate）刺激，以模拟昆虫取食。我们发现，与同种邻居一起生长的受刺激的 Centaurea maculosa 植物表现出总酚含量的增加，而与异种邻居一起生长的植物则将更多的资源分配到生长上。为了在野外进一步研究这些结果，我们进行了代谢组学分析，以探索在自然发生的同种和异种种群中生长的 Centaurea maculosa 个体之间的化学差异。与温室结果相似，当 Centaurea maculosa 个体在同种与异种种群中生长时，积累了更高水平的防御相关次生代谢物，而初级代谢物水平较低。两种林分类型的叶片取食量相似；然而，另一项单独的野外研究表明，专食性食草动物的负载与同种 Centaurea maculosa 密度呈正相关。
我们的结果表明，单个 Centaurea maculosa 植物可以根据其植物邻居的身份改变其防御策略。这可能对个体和群落的成功产生重要影响。
