Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET - UNLP, calles 47 y 115 (1900), La Plata, Buenos Aires, Argentina.
Department of Microbiology and Plant Pathology, University of California, Riverside, CA, 92521, USA.
Transgenic Res. 2020 Apr;29(2):215-228. doi: 10.1007/s11248-020-00191-1. Epub 2020 Jan 22.
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.
柑橘疱叶病（CPsV）缺乏天然抗性，因此需要采用转基因方法来培育抗 CPsV 的柑橘。为了评估赋予非转基因接穗抗性的可行性，我们通过嫁接将柑橘植株组装在一起，其中非转基因甜橙作为接穗，表达来自病毒外壳蛋白的内含子发夹（ihp）RNA 的 CPsV 抗性转基因甜橙系作为中间砧木，以及非转基因柑橘作为砧木。我们证明了 ihpCP 转录本通过嫁接从中间砧木转移到接穗中，触发外壳蛋白 mRNA 靶标的沉默。两次独立的 CPsV 挑战试验表明，中间砧木中 ihpCP 的表达提供了对中间砧木中 CPsV 的抗性，以及在非转基因接穗中不同程度的保护，这取决于病毒的传递部位。这些结果表明，嫁接是一种有前途的生物技术替代方法，可以保护木本植物免受无性繁殖植物中的病毒感染。
