作者：Kava-Cordeiro V, Rodríguez A, Vicent A, Glienke C, Peña L.
作者单位：Universidade Federal do Paraná (UFPR), Genética, Brazil
摘要：Citrus Black Spot (CBS) is a disease affecting sweet orange, lemons and mandarin varieties in Africa, Oceania and Americas. In Europe, CBS is a quarantine disease, limiting the import of fresh fruits from citrus-producing countries of those continents. CBS is caused by the fungus Phyllosticta citricarpa, which induces damages in fruit flavedo affecting their appearance and additionally causing premature fruit drop, thus reducing productivity. Its field control is currently based on the use of expensive fungicides. CBS symptoms are the consequence of fungal induced cell lyses and collapse around oil cavities. Such cells are responsible for the synthesis of essential oil. Orange fruit accumulates mainly terpenes in peel oil glands and D-limonene accounts for about 97% of oil glands content. In order to improve our understanding on the role of D-limonene and related terpenes in the interaction between orange flavedo tissues and the pathogen, we have used a P. citricarpa strain transformed with the reporter gene GFP to first develop a procedure to inoculate detached fruits in laboratory conditions and reliably get and follow fungal infection and symptoms in sweet orange. This has then served to compare the response to CBS challenge of fruits from transgenic orange plants carrying a D-limonene synthase gene in antisense (AS) configuration vs. empty vector (EV) transgenic controls. AS downregulation leads to a dramatic decrease in the accumulation of D-limonene in fruit peels, being about 80-100 times lower in AS samples than in EV transgenic ones. EV and AS transgenic fruits (141 and 140 mature fruits, respectively) were inoculated in four points, equally spaced intervals, with 5 μL of a conidia suspension (106). Fungal infection was evaluated daily and resulted to be very low or even absent in AS fruits while P. citricarpa readily developed in EV fruits. These results encourage the establishment of field trials with the transgenic events in CBS affected areas.
文献注录：Kava-Cordeiro V, Rodríguez A, Vicent A, Glienke C, Peña L.. D-limonene downregulation in transgenic sweet orange provides protection against Citrus Black Spot symptoms induced in detached fruits [A]. [C] Ⅶ International Citrus Congress. 2012.
报/刊名：《》，发表于2012
文献类型： [A]
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