Environ Exp Bot：河南农业大学丨水稻根部响应缺氧的分子机制研究（附NMT实验体系）
期刊：Environmental and Experimental Botany
主题：水稻根部响应缺氧的分子机制研究
标题：Comparative morphological and transcriptomic responses of lowland and upland rice to root-zone hypoxia
影响因子：3.712
检测指标：IAA、O2流速
检测样品：水稻（低地和高地两种）距根尖0,200, 300, 600, 900, 1200, 1500, 2500 μm
IAA、O2流速流实验处理方法：10日龄幼苗分别在充足氧（4.5-6.0 mg·L−1）和缺氧（0.9-2.1 mg·L−1）条件下培养5d
IAA、O2流速流实验测试液成份：0.1mM KCl, 0.1mM CaCl2, 0.1mM MgCl2, 0.3mM MES, pH 5.5
作者：河南农业大学赵全志、辛泽毓、刘娟
英文摘要
Lowland and upland rice, as for two ecotypes, that have been exhibited different tolerance levels under hypoxia conditions. However, the molecular mechanisms underlying rice root hypoxia tolerance between them are not fully understood.
This study was performed to assess the morphological, physiological and transcriptional changes of roots in one lowland rice YueFu (YF) and one upland rice IRAT109 (IR) genotype. A morpho-physiological analysis revealed that compared to IR, YF showed less reduction of root length, root and shoot biomass, formed more aerenchyma in the root, and kept more oxygen influxes in root under hypoxia conditions. Indole-3-acetic acid (IAA) fluxes patterns exhibited a different response to hypoxia in YF and IR.
The contents of IAA, ethylene and hydrogen peroxide were significantly increased in YF and IR, but nitric oxide significantly increased only in YF under hypoxic conditions. Subsequently, transcriptome analysis revealed that more differentially expressed genes (DEGs) were identified to respond to hypoxia in YF than IR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that DEGs in both genotypes enriched in energy metabolism, aerenchyma formation, reactive oxygen species, and cell wall modification, whereas more related DEGs in YF significantly enriched in these pathways than IR. The specific DEGs in YF especially enriched in phytohormone metabolism and signaling, such as auxin, jasmonic acid, and ethylene, but the specific DEGs in IR especially enriched in photosynthesis. All these results demonstrate that YF is more tolerant to hypoxia than IR, and elucidate some specific mechanisms underlying the differential hypoxia tolerance in lowland and upland rice.
This study has provided valuable candidate genes for genetic improvement of rice in adapting to hypoxia stress.
中文摘要（谷歌机翻译）
就两种生态型而言，低陆和旱稻在低氧条件下表现出不同的耐受水平。然而，它们之间的水稻根缺氧耐受性的分子机制尚不完全清楚。
这项研究的目的是评估一种低陆稻悦富（YF）和一种陆稻IRAT109（IR）基因型的根的形态，生理和转录变化。形态生理学分析表明，与IR相比，YF在低氧条件下显示的根长，根和茎生物量减少减少，在根中形成更多的气孔，并保持更多的氧流入。吲哚-3-乙酸（IAA）通量模式在YF和IR中显示出对缺氧的不同响应。
在低氧条件下，IAF，乙烯和过氧化氢的含量在YF和IR中显着增加，而一氧化氮仅在YF中显着增加。随后，转录组分析显示，与IR相比，鉴定出更多的差异表达基因（DEG）对YF缺氧有反应。基因本体论（GO）和《京都基因与基因组百科全书》（KEGG）分析表明，两种基因型的DEG均富含能量代谢，通气组织形成，活性氧种类和细胞壁修饰，而YF中更多相关的DEG则显着丰富了这些途径比红外线YF中的特定DEGs尤其富含植物激素代谢和信号传导，例如生长素，茉莉酸和乙烯，而IR中的特定DEGs尤其富含光合作用。所有这些结果表明，YF比IR更耐缺氧，并阐明了低陆稻和旱稻差异耐缺氧性的某些特定机制。
该研究为水稻遗传适应低氧胁迫提供了有价值的候选基因。
结果表明：在氧气充足（Aer）的条件下，分生区吸收O2比较剧烈。YF（低地品种）和IR（高地品种）在300μm处吸收的O2最多，其流速值分别达到79.14 pmol·cm−2·s−1和83.72 pmol·cm−2·s−1，而在缺氧（Hyp）条件下分别为44.77 pmol·cm−2·s−1和40.08 pmol·cm−2·s−1；IR明显降低的更多一些。这说明，分生区是水稻根部感受氧的关键区域，IR对缺氧条件更加敏感。
根分生区同时也是IAA较为敏感的区域。缺氧条件下，除IR的300μm处之外，两种水稻均表现为吸收IAA。氧气充足时，YF和IR在600μm处的IAA吸收速率分别为29,740 fmol·cm−2·s-1和35,092 fmol·cm−2·s-1；而在缺氧条件下分别为8864 fmol·cm−2·s-1和5441 fmol·cm−2·s-1。结合IAA含量测定结果，发现缺氧促使根部积累IAA。这说明生长素参与了缺氧条件下根系发育的调控过程。
文章链接：https://www.sciencedirect.com/science/article/pii/S0098847219315138?via%3Dihub
