Lee Choonseok, Chung Chong-Tae, Hong Woo-Jong, Lee Yang-Seok, Lee Jong-Hee, Koh Hee-Jong, Jung Ki-Hong
Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, South Korea.
Crop Research Division, Chungcheongnam-do Agricultural Research and Extension Services, Yesan, South Korea.
Front Plant Sci. 2021 Nov 8;12:748273. doi: 10.3389/fpls.2021.748273. eCollection 2021.
Global sea-level rise, the effect of climate change, poses a serious threat to rice production owing to saltwater intrusion and the accompanying increase in salt concentration. The reclaimed lands, comprising 22.1% of rice production in Korea, now face the crisis of global sea-level rise and a continuous increase in salt concentration. Here, we investigated the relationship between the decrease in seed quality and the transcriptional changes that occur in the developing rice seeds under salt stress. Compared to cultivation on normal land, the japonica rice cultivar, Samgwang, grown on reclaimed land showed a greatly increased accumulation of minerals, including sodium, magnesium, potassium, and sulfur, in seeds and a reduced yield, delayed heading, decreased thousand grain weight, and decreased palatability and amylose content. Samgwang showed phenotypical sensitivity to salt stress in the developing seeds. Using RNA-seq technology, we therefore carried out a comparative transcriptome analysis of the developing seeds grown on reclaimed and normal lands. In the biological process category, gene ontology enrichment analysis revealed that the upregulated genes were closely associated with the metabolism of biomolecules, including amino acids, carboxylic acid, lignin, trehalose, polysaccharide, and chitin, and to stress responses. MapMan analysis revealed the involvement of upregulated genes in the biosynthetic pathways of abscisic acid and melatonin and the relationship of trehalose, raffinose, and maltose with osmotic stress. Interestingly, many seed storage protein genes encoding glutelins and prolamins were upregulated in the developing seeds under salt stress, indicating the negative effect of the increase of storage proteins on palatability. Transcription factors upregulated in the developing seeds under salt stress included, in particular, bHLH, MYB, zinc finger, and heat shock factor, which could act as potential targets for the manipulation of seed quality under salt stress. Our study aims to develop a useful reference for elucidating the relationship between seed response mechanisms and decreased seed quality under salt stress, providing potential strategies for the improvement of seed quality under salt stress.
全球海平面上升作为气候变化的影响，由于海水入侵以及随之而来的盐分浓度增加，对水稻生产构成了严重威胁。韩国的开垦土地占水稻产量的22.1%，如今正面临全球海平面上升以及盐分浓度持续增加的危机。在此，我们研究了盐胁迫下发育中的水稻种子种子质量下降与转录变化之间的关系。与在正常土地上种植相比，在开垦土地上种植的粳稻品种“三光”种子中钠、镁、钾和硫等矿物质的积累大幅增加，产量降低、抽穗延迟、千粒重下降，适口性和直链淀粉含量降低。“三光”在发育中的种子中对盐胁迫表现出表型敏感性。因此，我们利用RNA测序技术对在开垦土地和正常土地上生长的发育中的种子进行了比较转录组分析。在生物学过程类别中，基因本体富集分析表明，上调的基因与包括氨基酸、羧酸、木质素、海藻糖、多糖和几丁质在内的生物分子代谢以及应激反应密切相关。MapMan分析揭示了上调基因参与脱落酸和褪黑素的生物合成途径以及海藻糖、棉子糖和麦芽糖与渗透胁迫的关系。有趣的是，许多编码谷蛋白和醇溶蛋白的种子贮藏蛋白基因在盐胁迫下发育中的种子中上调，表明贮藏蛋白增加对适口性有负面影响。盐胁迫下发育中的种子中上调的转录因子尤其包括bHLH、MYB、锌指和热激因子，它们可能是盐胁迫下调控种子质量的潜在靶点。我们的研究旨在为阐明盐胁迫下种子反应机制与种子质量下降之间的关系提供有用的参考，为盐胁迫下提高种子质量提供潜在策略。
