The lack of naturally occurring resistance to citrus psorosis virus (CPsV) necessitates a transgenic approach for the development of CPsV-resistant citrus. To evaluate the feasibility of conferring resistance to a non-transgenic scion, we have assembled citrus plants by grafting combining a non-transgenic Sweet Orange as scion, CPsV-resistant transgenic Sweet Orange lines expressing intron-hairpin (ihp) RNA derived from the viral coat protein (ihpCP) as interstock, and a non-transgenic citrus as rootstock. We demonstrated that ihpCP-transcripts translocate through the graft from interstock to scion, triggering the silencing of coat protein mRNA target. Two independent CPsV challenge assays showed that expression of ihpCP in the interstock provides resistance against CPsV in the interstock, and different levels of protection in the non-tg scion, depending of the virus delivery site. These results indicated that grafting is a promising biotechnological alternative to protect woody plants against virus infections in vegetative propagated plants.

中文翻译：

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在中间种群中表达发夹CP-mRNA的转基因甜橙赋予了非转基因接穗对柑桔牛皮癣病毒的耐受性。

缺乏对柑橘类牛皮癣病毒（CPsV）的自然抵抗力，因此需要一种转基因方法来开发对CPsV耐药的柑橘。为了评估赋予非转基因接穗抗药性的可行性，我们通过嫁接非转基因甜橙作为接穗组装了柑橘类植物，这些接穗表达了源自病毒的内含子发夹（ihp）RNA的CPsV抗性转基因甜橙品系外壳蛋白（ihpCP）作为中间砧木，非转基因柑桔作为砧木。我们证明了ihpCP转录物通过从中间砧到接穗的移植物转运，触发了外壳蛋白mRNA靶标的沉默。两项独立的CPsV攻击试验表明，中间存库中ihpCP的表达可提供中间存库中对CPsV的抗性，并且在非tg接穗中提供不同程度的保护，取决于病毒的传递站点。这些结果表明，嫁接是一种有前途的生物技术选择，可以保护木本植物免受无性繁殖植物的病毒感染。