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第一作者:Li Sun
第一单位:浙江大学
通讯作者:Shao Jian Zheng
Abstract
背景回顾:Iron (Fe) storage in plant seeds is not only necessary for seedling establishment following germination, but also a major source of dietary Fe for human and animal life. 提出问题:Seed Fe accumulation was known to be low during early seed development. However, the underlying mechanism and biological significance remain elusive. 结果1-INO过表达和降低表达表型:Here, we show that reduced expression of Arabidopsis YABBY transcription factor INNER NO OUTER (INO) increases embryonic Fe accumulation, while transgenic overexpression of INO has opposite effect. 结果2-INO表达模式及下游基因NRAMP1:INO is highly expressed during early seed development, and that decreased expression of INO increases the expression of NATURAL RESISTANCE ASSOCIATED MACROPHAGE PROTEIN 1 (NRAMP1), a gene encoding a transporter contributing to Fe loading into the seed. 结果3-NRAMP1作用于INO的下游-1:The relatively high embryonic Fe accumulation conferred by decreased expression of INO is rescued by the nramp1 loss-of-function mutation. 结果4-INO结合NRAMP1启动子:We further demonstrate that INO represses NRAMP1 expression by binding to NRAMP1 specific promoter region. 结果5-NRAMP1作用于INO的下游-2:Moreover, we show that excessive Fe loading into developing seeds in ino mutants produces more oxidative damage, leading to increased cell death and seed abortion, a phenotype that can be rescued by nramp1 mutation. 结论:Taken together, these results indicate that INO plays an important role in safeguarding reproduction by reducing Fe loading into developing seeds via repression of NRAMP1 expression. 摘 要
植物种子中的铁存储不仅是萌发后小苗生长所必需的,而且是人类和动物膳食铁的主要来源。在种子发育早期,种子铁积累保持在较低的水平。但是,潜在的分子机制以及生物学解释还不清楚。本文中,作者发现拟南芥YABBY转录因子INO表达量降低有助于胚胎铁积累的增加,而过表达INO具有相反的效果。INO基因在种子发育早期高表达,而INO基因的降低表达会增加一个作用于向种子运载铁的基因NRAMP1的高表达。nramp1功能缺失突变会使得INO表达量降低不在导致胚胎中高水平的铁积累。作者进一步的实验显示,INO可以通过直接结合到NRAMP1特异性启动子区域来抑制该基因的表达。此外,作者发现ino突变体正在发育的种子会积累过量的铁,引起更多的氧化应激损伤,导致细胞死亡增加、种子败育,而ino突变体的这种缺陷表型能够被nramp1突变拯救。综上,本文的研究结果揭示了INO通过抑制NRAMP1基因的表达,减少发育种子的铁积累,从而保证植物的生殖成功。
通讯作者
** 郑绍建 **
个人简介: 1986年,浙江农业大学,学士; 1991年,南京农业大学,博士。 研究方向:主要从事植物响应铝毒、缺铁、重金属毒害等营养逆境的生理和分子机制的研究。
doi: https://doi.org/10.1016/j.molp.2021.06.005
Journal: Molecular Plant
Published date: June 07, 2021
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