Fotelli Mariangela N, Lyrou Fani G, Avtzis Dimitrios N, Maurer Daniel, Rennenberg Heinz, Spyroglou Gavriil, Polle Andrea, Radoglou Kalliopi
Forest Research Institute, Hellenic Agricultural Organization Demeter, Thessaloniki, Greece.
Chair of Tree Physiology, Institute of Forest Sciences, University of Freiburg, Freiburg im Breisgau, Germany.
Front Plant Sci. 2020 Dec 10;11:581693. doi: 10.3389/fpls.2020.581693. eCollection 2020.
Aleppo pine () is widely distributed in the Mediterranean region and in other areas of the world, where it has been introduced due to its adaptive capacity to xerothermic conditions. The giant pine scale often infests Aleppo pine, as well as other pines, in several southeastern European countries, causing pine declines. When combined with the expected intensified heat and drought events in eastern Mediterranean, the impact of this biotic parameter on the host pines may be exacerbated. The importance of understanding the defense mechanisms of Aleppo pine is emphasized by the recent invasion of the pine scale in new regions, like Australia, lacking the insect's natural enemies, where more intense negative effects on pine species may occur. To date, Aleppo pine's physiological responses to the infestation by are largely unknown. This study aimed at assessing the responses of Aleppo pine to the giant pine scale attack, both on an ecophysiological and a metabolic level. For this purpose, gas exchange, needle water status, and carbon and nitrogen content were measured during 1 year on healthy and infested adult trees. M etabolic profiling of Aleppo pine needles was also performed before, during, and after the high feeding activity of the insect. The maintenance of stable relative water content, δC signatures, and chlorophyll fluorescence in the needles of infested pines indicated that infestation did not induce drought stress to the host pines. At the peak of infestation, stomatal closure and a pronounced reduction in assimilation were observed and were associated with the accumulation of sugars in the needles, probably due to impaired phloem loading. At the end of the infestation period, tricarboxylic acids were induced and phenolic compounds were enhanced in the needles of infested pines. These metabolic responses, together with the recovery of photosynthesis after the end of intense feeding, indicate that in the studied region and under the current climate, Aleppo pine is resilient to the infestation by the giant pine scale. Future research should assess whether these promising defense mechanisms are also employed by other host pines, particularly in regions of the world recently invaded by the giant pine scale, as well as under more xerothermic regimes.
阿勒颇松（）广泛分布于地中海地区及世界其他地区，因其对干热环境的适应能力而被引入这些地区。在欧洲东南部的几个国家，巨松蚧常常侵害阿勒颇松以及其他松树，导致松树衰退。再加上地中海东部预计会出现更强烈的高温和干旱事件，这一生物因素对寄主松树的影响可能会加剧。近期巨松蚧入侵澳大利亚等缺乏该昆虫天敌的新地区，对松树种类产生了更严重的负面影响，这凸显了了解阿勒颇松防御机制的重要性。迄今为止，阿勒颇松对巨松蚧侵害的生理反应在很大程度上尚不明确。本研究旨在评估阿勒颇松在生态生理和代谢水平上对巨松蚧攻击的反应。为此，在一年时间里对健康和受侵害的成年树木进行了气体交换、针叶水分状况以及碳和氮含量的测量。还在昆虫高取食活动之前、期间和之后对阿勒颇松针叶进行了代谢谱分析。受侵害松树针叶中相对含水量、δC特征和叶绿素荧光的稳定维持表明，侵害并未给寄主松树带来干旱胁迫。在侵害高峰期，可以观察到气孔关闭以及同化作用显著降低，这与针叶中糖分的积累有关，可能是由于韧皮部装载受损所致。在侵害期结束时，受侵害松树的针叶中三羧酸被诱导产生，酚类化合物含量增加。这些代谢反应，以及在强烈取食结束后光合作用的恢复，表明在所研究的地区和当前气候条件下，阿勒颇松对巨松蚧的侵害具有恢复能力。未来的研究应评估其他寄主松树是否也采用了这些有前景的防御机制，特别是在最近被巨松蚧入侵的世界其他地区，以及在更干热的环境下。
