Shannon Point Marine Center, Western Washington University, 1900 Shannon Point Road, Anacortes, WA, 98221, USA.
Sci Rep. 2023 Mar 15;13(1):4298. doi: 10.1038/s41598-023-30881-9.
Although the use of airborne molecules as infochemicals is common in terrestrial plants, it has not been shown to occur in an ecologically relevant context in marine seaweeds. Like terrestrial plants, intertidal plants spend part of their lives emersed at low tide and release volatile organic compounds (VOCs) into the air when they are grazed or physiologically stressed. We hypothesized seaweeds could use airborne VOCs as infochemicals and respond to them by upregulating a keystone defensive metabolite, dimethylsulfoniopropionate (DMSP). We conducted laboratory and field experiments in which Ulva fenestrata was exposed to airborne dimethyl sulfide (DMS), a volatile antiherbivore and antioxidant metabolite released when the seaweed is grazed or physiologically stressed. In the laboratory, U. fenestrata exposed to DMS had 43-48% higher DMSP concentrations, relative to controls, 6-9 days after exposure. In the field, U. fenestrata 1 m downwind of DMS emitters had 19% higher DMSP concentrations than upwind seaweeds after 11 days. To our knowledge, this is the first demonstration of a marine plant using an airborne molecule released when damaged to elicit defensive responses. Our study suggests that the ability to detect airborne compounds has evolved multiple times or before the divergence of terrestrial plants and green algae.
虽然空气中的分子作为信息素在陆生植物中很常见，但在生态上相关的海洋藻类中并没有发现这种情况。与陆生植物一样，潮间带植物在退潮时会有一部分时间暴露在空气中，并且当它们被放牧或受到生理压力时，会向空气中释放挥发性有机化合物（VOCs）。我们假设藻类可以利用空气中的 VOC 作为信息素，并通过上调关键防御代谢物二甲基硫丙酸酯（DMSP）来对此做出反应。我们进行了实验室和野外实验，其中 U. fenestrata 暴露于空气中的二甲基硫（DMS）中，这是一种挥发性的抗草食动物和抗氧化代谢物，当藻类被放牧或受到生理压力时会释放出来。在实验室中，暴露于 DMS 的 U. fenestrata 相对于对照组，在暴露后 6-9 天，DMSP 浓度增加了 43-48%。在野外，在 DMS 排放源下风处 1 米处的 U. fenestrata 的 DMSP 浓度比上风处的藻类高出 19%，在 11 天后。据我们所知，这是首次证明海洋植物利用受损时释放的空气中的分子来引发防御反应。我们的研究表明，检测空气中化合物的能力已经进化了多次，或者在陆生植物和绿藻分化之前就已经进化了。
