The CRISPR/Cas9 system has been used for genome editing in several plant species; however, there are few reports on its use in trees. Here, CRISPR/Cas9 was used to mutate a target gene in Populus alba × Populus glandulosa hybrid poplars. The hybrid poplar is routinely used in molecular biological studies due to the well-established Agrobacterium-mediated transformation method. A single guide RNA (sgRNA) with reported high mutation efficiency in other popular species was designed with a protospacer adjacent motif sequence for the phytoene desaturase 1 (PagPDS1) gene. The pHSE/Cas9-PagPDS1 sgRNA vector was delivered into hybrid poplar cells using Agrobacterium-mediated transformation. The transgenic plants were propagated and classified them into three groups according to their phenotypes. Among a total of 110 lines of transgenic hybrid poplars, 82 lines showed either an albino or a pale green phenotype, indicating around 74.5% phenotypic mutation efficiency of the PagPDS1 gene. The albino phenotypes were observed when the CRISPR/Cas9-mediated mutations in both PagPDS1 alleles in the transgenic plants. There was no off-target modification of the PagPDS2 gene, which has a potential sgRNA target sequence with two mismatches. The results confirmed that the sgRNA can specifically edit PagPDS1 rather than PagPDS2, indicating that CRISPR/Cas9-mediated genome editing can effectively induce target mutations in the hybrid poplar. This technique will be useful to improve tree quality in hybrid poplars (P. alba × P. glandulosa); for example, by enhancing biomass or stress tolerance.

CRISPR/Cas9系统已用于多种植物物种的基因组编辑；然而，关于其在树木中的应用的报道很少。在这里，CRISPR/Cas9被用来突变白杨×腺杨杂种杨树中的目标基因。由于成熟的农杆菌介导的转化方法，杂交杨树常用于分子生物学研究。据报道，在其他流行物种中具有高突变效率的单指导 RNA (sgRNA) 被设计为带有八氢番茄红素去饱和酶 1 ( PagPDS1 ) 基因的原型间隔子相邻基序序列。使用农杆菌介导的转化将pHSE/Cas9- PagPDS1 sgRNA载体递送至杂交杨细胞中。繁殖转基因植物并根据其表型将它们分为三组。在总共110个转基因杂交杨品系中，82个品系表现出白化或淡绿色表型，表明PagPDS1基因的表型突变效率约为74.5%。当转基因植物中两个PagPDS1等位基因发生 CRISPR/Cas9 介导的突变时，观察到白化表型。 PagPDS2基因没有脱靶修饰，该基因的潜在 sgRNA 靶序列有两个错配。结果证实，sgRNA可以特异性编辑PagPDS1而不是PagPDS2 ，这表明CRISPR/Cas9介导的基因组编辑可以有效诱导杂交杨中的目标突变。该技术将有助于提高杂交杨树（白杨×腺杨）的树质；例如，通过增强生物量或胁迫耐受性。