2020年8月27日,中国农业科学院蔬菜花卉研究所甘蓝青花菜研究团队在期刊planta(2023 IF=4.3)上发表了题为An efficient virus‑induced gene silencing (VIGS) system for functional genomics in Brassicas using a cabbage leaf curl virus (CaLCuV)‑based vector的研究论文。论文的第一作者为肖志亮博士,通讯作者为庄木研究员和吕红豪研究员。
病毒诱导的基因沉默(Virus-induced gene silencing,VIGS)是一种转录后基因沉默方法,是分析植物基因功能的有效技术。然而,迄今为止在甘蓝(Brassica oleracea)中尚无可用的VIGS载体。在这项研究中,选择了烟草拟杆状病毒(tobacco rattle virus,TRV)、pTYs和卷叶病毒(cabbage leaf curl virus,CaLCuV)基因沉默载体,以PDS(突变白化)基因作为VIGS的标志基因。我们成功沉默了PDS的表达,并观察到了甘蓝在pTYs和CaLCuV的作用下发生的白化现象,其中后者更易操作且成本更低。随后,比较了影响CaLCuV在甘蓝中的VIGS效率。优化后的基于CaLCuV的VIGS系统最优注射方法为:约500 bp的插入序列、农杆菌浓度(OD600)为1.0、在苗期应用注射器注射法,以及培养温度为22 °C。在这种条件下,CaLCuV有65%的稳定沉默效率。为了进一步测试VIGS系统的有效性,作者选择了甘蓝的ChlH基因并降低其表达,观察到了如预期的黄叶现象。随后,作者成功地将基于CaLCuV的VIGS系统应用于另外两个代表性的芸苔属作物种类,即白菜(B. rapa)和芥菜(B. nigra)。
Fig. 1 Relative position and length of the BoPDS cDNA fragments used for silencing relative to those of the full-length CDS
Fig. 4 qRT-PCR analysis of PDS in various tissues of cabbage inoculated with CaLCuV, pTYs and TRV The error bars represent the ± SE of three independent experiments (P ≤ 0.05)
Fig. 5 Silencing efficiency using different post-treatment approaches. The ‘Optimum’ CaLCuV-based VIGS system involves the following: an approximately 500 bp insert sequence, an Agrobacterium OD600 of 1.0, use of the vacuum osmosis method applied at the bud stage, and an incubation temperature of 22 °C. Each value is the mean of three replicates of 20 seedlings. The error bars show the ± SE of three independent experiments (P ≤ 0.05)
Fig. 7 a-c Photobleaching phenotypes of B. rapa, B. nigra and B. campestris, respectively, using CaLCuV-based vectors. Controls shown in the upper row