Data from: Invasive mutualisms between a plant pathogen and insect vectors in the Middle East and Brazil

Complex multi-trophic interactions in vectorborne diseases limit our understanding and ability to predict outbreaks. Arthropod-vectored pathogens are especially problematic, with the potential for novel interspecific interactions during invasions. Variations and novelties in plant–arthropod–pathogen triumvirates present significant threats to global food security. We examined aspects of a phytoplasma pathogen of citrus across two continents. ‘Candidatus Phytoplasma aurantifolia’ causes Witches' Broom Disease of Lime (WBDL) and has devastated citrus production in the Middle East. A variant of this phytoplasma currently displays asymptomatic or ‘silent’ infections in Brazil. We first studied vector capacity and fitness impacts of the pathogen on its vectors. The potential for co-occurring weed species to act as pathogen reservoirs was analysed and key transmission periods in the year were also studied. We demonstrate that two invasive hemipteran insects—Diaphorina citri and Hishimonus phycitis—can vector the phytoplasma. Feeding on phytoplasma-infected hosts greatly increased reproduction of its invasive vector D. citri both in Oman and Brazil; suggesting that increased fitness of invasive insect vectors thereby further increases the pathogen's capacity to spread. Based on our findings, this is a robust system for studying the effects of invasions on vectorborne diseases and highlights concerns about its spread to warmer, drier regions of Brazil.

媒介传播疾病中复杂的多营养级互作，限制了我们对疾病暴发的认知与预测能力。节肢动物媒介传播的病原体问题尤为突出，其在入侵过程中可能产生全新的种间互作关系。植物-节肢动物-病原体三元互作体系的变异与新特征，对全球粮食安全构成重大威胁。我们针对两大洲的柑橘植原体（phytoplasma）病原体开展了相关研究。‘柠檬丛枝病植原体’（Candidatus Phytoplasma aurantifolia）可引发酸橙丛枝病（Witches' Broom Disease of Lime, 简称WBDL），曾重创中东地区的柑橘产业。目前，该植原体的一个变异株在巴西呈现无症状或‘隐性’侵染状态。我们首先探究了该病原体对其媒介昆虫的传毒能力及适合度影响，同时分析了伴生杂草物种充当病原体储藏宿主的潜在可能，并对年度内的关键传毒周期展开了研究。本研究证实，两种入侵性半翅目昆虫——柑橘木虱（Diaphorina citri）与Hishimonus phycitis——可传播该植原体。取食植原体侵染寄主的行为，大幅提升了入侵媒介柑橘木虱（简称D. citri）在阿曼与巴西的繁殖能力；这表明入侵昆虫媒介适合度的提升，会进一步增强该病原体的传播能力。基于本研究结果，该体系可作为探究入侵事件对媒介传播疾病影响的稳健研究模型，同时也凸显了该病原体向巴西气候更温暖干燥区域扩散的潜在风险。