CRISPR/Cas9‐mediated editing of 1‐aminocyclopropane‐1‐carboxylate oxidase1 (ACO1) enhances Petunia flower longevity

First author: Junping Xu; Affiliations: Kyungpook National University (庆北国立大学): Daegu, South Korea

Corresponding author: Chang Kil Kim

The genes that encode the ethylene biosynthesis enzyme 1‐aminocyclopropane‐1‐carboxylate oxidase (ACO) are thought to be involved in flower senescence. Hence, we investigated whether the transcript levels of PhACO genes (PhACO1, PhACO3, and PhACO4) in Petunia cv. Mirage Rose are associated with ethylene production at different flowering stages. High transcript levels were detected in the late flowering stage and linked to high ethylene levels. PhACO1 was subsequently edited using the CRISPR/Cas9 system and its role in ethylene production was investigated. PhACO1‐edited T0 mutant lines, regardless of mutant type (homozygous or monoallelic), exhibited significantly reduced ethylene production and enhanced flower longevity compared to wild‐type (WT). Flower longevity and the reduction in ethylene production were observed to be stronger in homozygous plants than in their monoallelic counterparts. Additionally, the transmission of the edited gene to the T1 (lines 6 and 36) generation was also confirmed, with the results for flower longevity and ethylene production proving to be identical to those of the T0 mutant lines. Overall, this study increases the understanding of the role of PhACO1 in petunia flower longevity and also points to the CRISPR/Cas9 system being a powerful tool in the improvement of floricultural quality.

编码乙烯生物合成酶1-氨基环丙烷-1-羧酸氧化酶ACO的基因被认为参与了花序的发育。因此，作者调查了矮牵牛不同花发育阶段中ACO基因PhACO1、PhACO3和PhACO4是否与乙烯的产量相关。作者在花发育晚期检测到了ACO基因的高表达，同时还有高水平的乙烯含量。作者利用CRISPR/Cas9系统编辑了PhACO1基因，并研究了其在乙烯合成中的作用。与野生型相比，PhACO1编辑的T0代突变体株系，无论是纯合突变体还是单等位基因的突变体，均存在显著的乙烯产量降低表型，并且花的寿命延长。而且，在纯合突变体株系中，花的寿命延长以及乙烯产量下降的水平均要比单等位基因突变体的表型更加强烈。另外，作者在T1代株系6和36中也检测到了被编辑PhACO1基因，并且这两个株系有关花寿命和乙烯产量的表型与T0代突变体一致。综上，本文的研究揭示了PhACO1基因作用于矮牵牛花的长寿，同时也表明CRISPR/Cas9系统可以用于花卉品质的改良。

通讯：Chang Kil Kim (https://en.knu.ac.kr/research/researcher01_04.htm)

doi: https://doi.org/10.1111/pbi.13197

Journal: Plant Biotechnology Journal

First Published: June 21, 2019