Kobayashi Yasufumi, Fujita Yasunari
Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki 305-8686, Japan.
Food Program, JIRCAS, Tsukuba, Ibaraki 305-8686, Japan.
Plant Biotechnol (Tokyo). 2024 Dec 25;41(4):447-452. doi: 10.5511/plantbiotechnology.24.0807a.
Quinoa, a pseudocereal and leafy vegetable native to South America, is highly nutritious and can grow in harsh environments. One of the most prominent morphological features of quinoa is that the above-ground portion is covered with a layer of epidermal bladder cells (EBCs), and the role of EBCs in quinoa's high stress tolerance is of interest. Recent studies have shown that two WD40-repeat proteins, Reduced number of EBC (REBC) and REBC-like1, are required for EBC formation and that EBCs contribute defense mechanisms against biotic stress rather than abiotic stress. However, the role of EBCs in drought stress tolerance remains controversial due to the pleiotropic effects of these genes, including their impact on plant growth. Here, we show that REBC and REBC-like1 mediate water retention in detached quinoa leaves. Using a virus-induced gene silencing (VIGS) system, we found that downregulation of both and had no apparent effect on plant growth, but reduced the number of EBCs in both lowland and highland quinoa lines. Further, downregulation of both genes increased water loss in detached leaves of quinoa plants, supporting the notion that EBCs mediate water retention in quinoa leaves. Interestingly, we found higher EBC density in the southern highland lines grown in drier areas. Thus, we demonstrate that the effective use of VIGS in the analysis of genes with pleiotropic effects allows analyses that were difficult to perform using mutants alone, and that unlike mutants, functional genomics studies of quinoa can be easily performed in various lines using VIGS.
藜麦是一种原产于南美洲的假谷物和叶菜类蔬菜，营养丰富，能在恶劣环境中生长。藜麦最显著的形态特征之一是地上部分覆盖着一层表皮囊泡细胞（EBCs），EBCs在藜麦高胁迫耐受性中的作用备受关注。最近的研究表明，两种WD40重复蛋白，即表皮囊泡细胞数量减少蛋白（REBC）和类REBC1，是EBC形成所必需的，并且EBCs有助于抵御生物胁迫而非非生物胁迫的防御机制。然而，由于这些基因的多效性影响，包括它们对植物生长的影响，EBCs在耐旱胁迫耐受性中的作用仍存在争议。在此，我们表明REBC和类REBC1介导离体藜麦叶片的水分保持。使用病毒诱导基因沉默（VIGS）系统，我们发现下调这两个基因对植物生长没有明显影响，但减少了低地和高地藜麦品系中的EBC数量。此外，下调这两个基因增加了藜麦植株离体叶片的水分流失，支持了EBCs介导藜麦叶片水分保持的观点。有趣的是，我们发现在较干燥地区种植的南部高地品系中EBC密度更高。因此，我们证明了VIGS在多效性基因分析中的有效应用使得单独使用突变体难以进行的分析成为可能，并且与突变体不同，藜麦的功能基因组学研究可以使用VIGS在各种品系中轻松进行。
