Diurnal rhythms in durum wheat triggered by Rhopalosiphum padi (bird cherry-oat aphid)

Wheat is a staple crop and one of the most widely consumed grains globally Wheat yields can experience significant losses due to the damaging effects of herbivore infestation However little is known about the effect aphids have on the natural diurnal rhythms in plants Our timeseries transcriptomics and metabolomics study reveals intriguing molecular changes occurring in plant diurnal rhythmicity upon aphid infestation Under control conditions 15366 out of the 66559 genes in the tetraploid wheat cultivar Svevo representing approximately 25 of the transcriptome exhibited diurnal rhythmicity Upon aphid infestation 5682 genes lost their rhythmicity while 5203 genes began to exhibit diurnal rhythmicity only in the presence of aphids The genes exhibiting aphid induced rhythmicity were associated with defense related GO terms such as protein phosphorylation and cellular response to ABA and were enriched with motifs of the WRKY transcription factor families Conversely the genes showing aphid-inhibited rhythmicity were enriched for motifs of TCP and ERF transcription factor families While the core circadian clock genes maintain their rhythmicity during infestation we observed that approximately 60 of rhythmic genes experience disruptions in their rhythms during aphid infestation These changes can influence both the plants growth and development processes as well as defense responses Furthermore analysis of rhythmic metabolite composition revealed that several monoterpenoids gained rhythmic activity under infestation while saccharides retained their rhythmic patterns Our findings highlight the ability of insect infestation to disrupt the natural diurnal cycles in plants expanding our knowledge of the complex interactions between plants and insects

小麦是全球主粮作物之一，亦是全球范围内被广泛消费的谷物之一。小麦产量常因植食性昆虫侵害蒙受严重损失，但目前学界对蚜虫侵染如何影响植物天然昼夜节律的认知仍相对匮乏。本研究通过时序转录组学（timeseries transcriptomics）与代谢组学（metabolomics）分析，揭示了蚜虫侵染后植物昼夜节律发生的引人关注的分子变化。
在对照组条件下，四倍体小麦栽培品种Svevo的66559个基因中，有15366个（约占转录组的25%）呈现出昼夜节律性表达。当受到蚜虫侵染后，5682个基因丧失了节律性表达，另有5203个基因仅在蚜虫侵染条件下才呈现出昼夜节律性。受蚜虫诱导获得节律性的基因，与蛋白质磷酸化、细胞对脱落酸（ABA）的应答等基因本体论（Gene Ontology）注释条目相关，并富集有WRKY转录因子家族的结合基序。与之相反，被蚜虫抑制节律性表达的基因，则富集有TCP与ERF转录因子家族的结合基序。
尽管核心生物钟基因在侵染过程中仍维持自身节律性，但我们观察到约60%的节律表达基因在蚜虫侵染期间出现了节律紊乱。此类变化可同时影响植物的生长发育过程与防御应答反应。此外，对节律性代谢物组成的分析显示，多种单萜类化合物（monoterpenoids）在侵染条件下获得了节律性积累特性，而糖类物质则维持了原有的节律模式。本研究结果证实了昆虫侵染可扰乱植物天然昼夜周期，进一步深化了学界对植物与昆虫间复杂互作关系的认知。