Arbuscular mycorrhizal fungi and aphids interact by changing host plant quality and volatile emission
Arbuscular mycorrhizal fungi and aphids interact by changing host plant quality and volatile emission
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DOI：
10.1111/1365-2435.12181
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发表时间：
2014-04-01
影响因子：
5.2
通讯作者：
Johnson, David
中科院分区：
文献类型：
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作者：
Babikova, Zdenka;Gilbert, Lucy;Johnson, David
1. 大多数植物与丛枝菌根真菌（AM）和蚜虫等食草动物相互作用，前者增加了养分的获取，后者从植物中吸取养分。AM真菌和蚜虫都可以影响植物的代谢途径，并可能通过改变共同寄主植物的状况而相互影响。本研究同时测试了AM真菌对蚜虫相互作用的影响（自下而上效应）和蚜虫对AM真菌相互作用的影响（自上而下效应）。我们假设：(1)AM真菌或蚜虫诱导植物挥发性有机化合物（VOCs）产生变化，从而调节植物对蚜虫的吸引力；（ii）蚜虫减少AM真菌定植；(3) AM真菌定殖影响蚜虫的发育。蚕豆暴露于AM真菌，蚜虫和两者的组合。为了测试自下而上和自上而下效应的强度，分别在蚜虫添加到植物之前或之后进行处理，以建立菌根。植物产生的挥发性有机化合物被用来(i)测试它们对蚜虫的吸引力，（ii）识别引起吸引力的化学物质。我们还测量了植物的生长和营养，AM真菌定植和蚜虫繁殖。AM真菌增加了植物对蚜虫的吸引力，这种效应甚至对蚜虫感染的植物也普遍存在。然而，蚜虫的吸引力和种群增长都取决于AM真菌接种的时间。AM真菌抑制了倍半萜烯(E)-石竹烯和(E)-b-法尼烯的释放，蚜虫对挥发性有机化合物的吸引力与样品中倍半萜烯的比例呈负相关。(Z)-3-乙酸己烯酯、萘和(R)-锗烯D的释放受蚜虫与AM真菌相互作用的调控。蚜虫对菌根定植、植物生物量和营养有负面影响。我们的数据表明，地下和地上的生物可以通过改变它们共有的寄主植物的质量来相互作用，即使它们之间没有直接接触。植物与食草动物和AM真菌的相互作用是双向的：AM真菌通过增加植物挥发性有机化合物对蚜虫的吸引力，在昆虫寄主定位中起着关键的自下而上的作用，而蚜虫则抑制AM共生的形成。
1. Most plants interact with both arbuscular mycorrhizal (AM) fungi, which increase nutrient acquisition, and herbivores such as aphids, which drain nutrients from plants. Both AM fungi and aphids can affect plant metabolic pathways and may influence each other by altering the condition of the shared host plant.2. This study tests simultaneously the effects of AM fungi on interactions with aphids (bottom-up effects) and the effects of aphids on interactions with AM fungi (top-down effects). We hypothesized that: (i) attractiveness of plants to aphids is regulated by induced changes in production of plant volatile organic compounds (VOCs) triggered by AM fungi or aphids; (ii) aphids reduce AM fungal colonization; and (iii) AM fungal colonization affects aphid development.3. Broad beans were exposed to AM fungi, aphids and a combination of both. To test for the strength of bottom-up and top-down effects, separate treatments enabled establishment of mycorrhizas either before or after aphids were added to plants. VOCs produced by plants were used to (i) test their attractiveness to aphids and (ii) identify the semiochemicals causing attraction. We also measured plant growth and nutrition, AM fungal colonization and aphid reproduction.4. AM fungi increased the attractiveness of plants to aphids, and this effect tended to prevail even for aphid-infested plants. However, both attractiveness and aphid population growth depended on the timing of AM fungal inoculation. AM fungi suppressed emission of the sesquiterpenes (E)-caryophyllene and (E)-b-farnesene, and aphid attractiveness to VOCs was negatively associated with the proportion of sesquiterpenes in the sample. Emission of (Z)-3-hexenyl acetate, naphthalene and (R)-germacrene D was regulated by an interaction between aphids and AM fungi. Aphids had a negative effect on mycorrhizal colonization, plant biomass and nutrition.5. Our data show that below- and above-ground organisms can interact by altering the quality of their shared host plant even though there is no direct contact between them. Plant interactions with herbivores and AM fungi operate in both directions: AM fungi have a key bottom-up role in insect host location by increasing the attractiveness of plant VOCs to aphids, whereas aphids inhibit formation of AM symbioses.