Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 206, 33100, Udine, Italy.
IGA Technology Services, Via Jacopo Linussio, 51, 33100, Udine, Italy.
BMC Genomics. 2019 Sep 10;20(1):703. doi: 10.1186/s12864-019-6062-x.
'Candidatus Phytoplasma solani' is endemic in Europe and infects a wide range of weeds and cultivated plants. Phytoplasmas are prokaryotic plant pathogens that colonize the sieve elements of their host plant, causing severe alterations in phloem function and impairment of assimilate translocation. Typical symptoms of infected plants include yellowing of leaves or shoots, leaf curling, and general stunting, but the molecular mechanisms underlying most of the reported changes remain largely enigmatic. To infer a possible involvement of Fe in the host-phytoplasma interaction, we investigated the effects of 'Candidatus Phytoplasma solani' infection on tomato plants (Solanum lycopersicum cv. Micro-Tom) grown under different Fe regimes.
Both phytoplasma infection and Fe starvation led to the development of chlorotic leaves and altered thylakoid organization. In infected plants, Fe accumulated in phloem tissue, altering the local distribution of Fe. In infected plants, Fe starvation had additive effects on chlorophyll content and leaf chlorosis, suggesting that the two conditions affected the phenotypic readout via separate routes. To gain insights into the transcriptional response to phytoplasma infection, or Fe deficiency, transcriptome profiling was performed on midrib-enriched leaves. RNA-seq analysis revealed that both stress conditions altered the expression of a large (> 800) subset of common genes involved in photosynthetic light reactions, porphyrin / chlorophyll metabolism, and in flowering control. In Fe-deficient plants, phytoplasma infection perturbed the Fe deficiency response in roots, possibly by interference with the synthesis or transport of a promotive signal transmitted from the leaves to the roots.
'Candidatus Phytoplasma solani' infection changes the Fe distribution in tomato leaves, affects the photosynthetic machinery and perturbs the orchestration of root-mediated transport processes by compromising shoot-to-root communication.
“植原体 Solani”在欧洲流行，感染范围广泛的杂草和栽培植物。植原体是一种原核植物病原体，定植在其宿主植物的筛管中，导致韧皮部功能严重改变和同化产物转运受损。受感染植物的典型症状包括叶片或嫩枝变黄、叶片卷曲和整体生长不良，但大多数报道的变化背后的分子机制仍在很大程度上是个谜。为了推断铁在宿主-植原体相互作用中的可能参与，我们研究了“植原体 Solani”感染对不同铁处理条件下生长的番茄植株（Solanum lycopersicum cv. Micro-Tom）的影响。
植原体感染和铁饥饿都导致了叶片失绿和类囊体组织的改变。在感染的植物中，铁在韧皮部组织中积累，改变了铁的局部分布。在感染的植物中，铁饥饿对叶绿素含量和叶片黄化有累加效应，表明这两种情况通过不同的途径影响表型。为了深入了解植原体感染或铁缺乏对转录的影响，我们对中肋富集叶片进行了转录组谱分析。RNA-seq 分析表明，两种胁迫条件都改变了与光合作用光反应、卟啉/叶绿素代谢和开花控制相关的大量（>800）常见基因的表达。在缺铁植物中，植原体感染扰乱了根部的铁缺乏反应，可能是通过干扰从叶片传递到根部的促进信号的合成或运输。
“植原体 Solani”感染改变了番茄叶片中的铁分布，影响了光合作用机制，并通过破坏地上部与根部的通讯来扰乱根部介导的运输过程的协调。
