Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China.
Hunan Tobacco Research Institute, Changsha, China.
Planta. 2020 Jul 3;252(1):13. doi: 10.1007/s00425-020-03418-x.
NtALS1 is specifically expressed in glandular trichomes, and can improve the content of acylsugars in tobacco.
The glandular trichomes of many species in the Solanaceae family play an important role in plant defense. These epidermal outgrowths exhibit specialized secondary metabolism, including the production of structurally diverse acylsugars that function in defense against insects and have substantial developmental potential for commercial uses. However, our current understanding of genes involved in acyl chain biosynthesis of acylsugars remains poor in tobacco. In this study, we identified three acetolactate synthase (ALS) genes in tobacco through homology-based gene prediction using Arabidopsis ALS. Quantitative real-time PCR (qRT-PCR) and tissue distribution analyses suggested that NtALS1 was highly expressed in the tips of glandular trichomes. Subcellular localization analysis showed that the NtALS1 localized to the chloroplast. Moreover, in the wild-type K326 variety background, we generated two ntals1 loss-of-function mutants using the CRISPR-Cas9 system. Acylsugars contents in the two ntals1 mutants were significantly lower than those in the wild type. Through phylogenetic tree analysis, we also identified NtALS1 orthologs that may be involved in acylsugar biosynthesis in other Solanaceae species. Taken together, these findings indicate a functional role for NtALS1 in acylsugar biosynthesis in tobacco.
NtALS1 特异性表达于腺毛中，并能提高烟草中酰基糖的含量。
茄科许多物种的腺毛在植物防御中起着重要作用。这些表皮突起表现出专门的次生代谢，包括产生结构多样的酰基糖，这些酰基糖在防御昆虫方面具有功能，并且在商业用途方面具有巨大的发展潜力。然而，我们目前对烟草中酰基糖酰基链生物合成相关基因的了解还很有限。本研究通过基于同源性的基因预测，利用拟南芥 ALS 基因在烟草中鉴定出三个乙酰乳酸合酶（ALS）基因。实时定量 PCR（qRT-PCR）和组织分布分析表明，NtALS1 在腺毛尖端高度表达。亚细胞定位分析表明，NtALS1 定位于叶绿体。此外，在野生型 K326 品种背景下，我们利用 CRISPR-Cas9 系统生成了两个 ntals1 功能丧失突变体。这两个 ntals1 突变体中的酰基糖含量明显低于野生型。通过系统发育树分析，我们还鉴定出 NtALS1 的直系同源物，这些同源物可能参与其他茄科物种的酰基糖生物合成。综上所述，这些发现表明 NtALS1 在烟草酰基糖生物合成中具有功能作用。
