Huanglongbing (HLB) is the main disease of citriculture worldwide, being mainly caused by the bacterium known as ‘Candidatus Liberibacter asiaticus’ (CLas), limited to the phloem and naturally transmitted by vector insects known as psyllids. For the production of citrus seedlings, it is necessary to use rootstocks that are propagated by seeds from fruits produced by mother plants grown in field, however being submitted to natural HLB transmission. Although there is no evidence of CLas transmission from seeds to seedlings, little is known about the effects of this bacterium on the physiological quality of seeds obtained from CLas-infected plants. Therefore, the aim of this work was to evaluate the physiological quality of seeds from ‘Rangpur’ lime and ‘Swingle’ citrumelo rootstocks, from CLas-infected plants, with symptomatic and asymptomatic branches. The parameters evaluated, in addition to fruit development in mother plants, were germination rate, tetrazolium test, electrical conductivity, seedling emergence in greenhouse, and vegetative development and molecular analysis via qPCR for the detection of bacteria (leaf petiole, fruit peduncles, roots, seed coats, and seed endosperm). The presence of CLas in plants of both rootstocks has negative impact on fruit development, as well as on the number of normal seeds. In addition, there is reduced germination and seed emergence. Although CLas was detected in different tissues (leaf petiole, fruit peduncles and seed coat, and seed embryo), no vertical bacteria transmission was detected. Results have shown that seeds from CLas-infected branches have impaired physiological quality, but without bacterial transmission from seeds to seedlings.

中文翻译：

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HLB对柑橘砧木种子生理品质和非垂直'Candidatus Liberibacter asiaticus'传播的影响

黄龙病（HLB）是世界范围内柑橘养殖的主要疾病，主要由被称为“Candidatus Liberibacter asiaticus”（CLas）的细菌引起，仅限于韧皮部，由称为木虱的媒介昆虫自然传播。对于柑橘幼苗的生产，必须使用由田间种植的母本植物产生的果实的种子繁殖的砧木，但要进行自然 HLB 传播。虽然没有证据表明 CLas 从种子传播到幼苗，但人们对这种细菌对从 CLas 感染的植物中获得的种子的生理质量的影响知之甚少。因此，这项工作的目的是评估来自 CLas 感染植物的 'Rangpur' 石灰和 'Swingle' 柑橘砧木种子的生理质量，有症状和无症状的分支。除了母株的果实发育外，评估的参数还有发芽率、四唑试验、电导率、温室中的幼苗出苗，以及通过 qPCR 检测细菌（叶柄、果梗、根、种皮和种子胚乳）。两种砧木植物中CLas的存在对果实发育以及正常种子的数量具有负面影响。此外，发芽和种子出现减少。尽管在不同组织（叶柄、果梗和种皮、种胚）中检测到了CLas，但未检测到细菌垂直传播。结果表明，CLas 感染枝条的种子生理质量受损，