Abstract

The biological and molecular traits of the Ponkan mandarin (Citrus reticulata Blanco) were characterized in an investigation of the mechanisms of field resistance against citrus canker disease caused by the bacterial pathogen, Xanthomonas citri subsp. citri (Xcc). Various conventional citrus varieties that show diverse responses to Xcc were investigated, and the temporal changes in Xcc titer in response to linalool concentrations among the varieties revealed differences in Xcc proliferation trends in the inoculated leaves of the immune, field-resistant, and susceptible varieties. In addition, increased linalool accumulation was inversely related to Xcc titers in the field-resistant varieties, which is likely caused by host-pathogen interactions. Quantitative trait locus (QTL) analysis using the F₁ population of the resistant Ponkan mandarin and susceptible ‘Harehime’ (‘E-647’ × ‘Miyagawa-wase’) cultivar revealed that linalool accumulation and Xcc susceptibility QTLs overlapped. These results provide novel insights into the molecular mechanisms of linalool-mediated field resistance to Xcc, and suggest that high linalool concentrations in leaves has an antibacterial effect and become a candidate-biomarker target for citrus breeding to produce seedlings with linalool-mediated field resistance against Xcc.

中文翻译：

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芳樟醇介导的对柑橘黄单胞菌亚种的场抗性的生物学和分子表征。柑橘树上的柑橘

摘要

在研究由细菌病原体柑橘黄单胞菌引起的柑橘溃疡病的田间抗性机制时，对椴柑（Citrus reticulata Blanco）的生物学和分子特征进行了表征。柑橘（Xcc）。研究了对Xcc表现出不同反应的各种常规柑橘品种，并且Xcc效价随品种间芳樟醇浓度的时间变化揭示了免疫、田间抗性和易感品种的接种叶片中Xcc增殖趋势的差异。此外，芳樟醇积累的增加与田间抗性品种中的Xcc滴度，这可能是由宿主 - 病原体相互作用引起的。使用抗性椴柑和易感'Harehime'（'E-647'×'Miyagawa-wase'）品种的F ₁种群的数量性状基因座（QTL）分析显示芳樟醇积累和Xcc易感性QTL 重叠。这些结果为深入了解芳樟醇介导的田间抗Xcc的分子机制提供了新的见解，并表明叶片中高浓度芳樟醇具有抗菌作用，并成为柑橘育种的候选生物标志物靶标，以产生芳樟醇介导的田间抗 Xcc 幼苗。Xcc。