Plant Physiol:浙江大学郑绍建教授实验室发表植物学研究论文
2016年5月19日，国际植物学顶级期刊《plant Physiology》杂志上在线发表了浙江大学生命科学学院郑绍建教授实验室发表关于植物内铁元素缺失的研究论文，论文题为“A WRKY transcription factor regulates Fe translocation under Fe deficiency in Arabidopsi”博士生颜晶莹为论文第一作者，丁忠杰博士后为通讯作者。
铁是植物必需的微量营养元素，而在碱性/石灰性土壤上由于有效铁含量水平不能满足植物正常生长需要，很易出现缺铁而导致的新叶失绿现象，从而严重影响农作物生产的正常生长，并导致减产减收和影响农产品的营养品质。世界上大约有30%左右的可耕地属于碱性/石灰性土壤，我国北方和沿海地区也广为分布。耐缺铁的植物可通过诱导特异的根系形态和生理生化特性来提高根系对土壤中铁的活化能力和吸收能力，但对植物是否可通过提高铁在体内的利用效率来改善地上部分的铁营养的研究相对较少。我们实验室在前期的研究中发现缺铁诱导分泌的酚类化合物可通过提高根系质外铁的再利用而缓解地上部分的缺铁症状，且此过程受ABA的进一步促进(Jin et al., 2007. Plant Physiology. 144:279-285; Lei et al., 2014. Plant Cell & Envrionment. 37:852-863)。本研究中，我们发现转录因子WRKY46的T-DNA插入突变体对缺铁非常敏感，而过表达株系对缺铁的抗性增强;体内铁含量分析表明，突变体根系铁含量增加，但地上部分铁含量明显下降，与之相应的是伤流液中的铁浓度也显著下降，说明WRKY46影响了铁从根系向地上部分的转运。我们通过基因芯片分析，并结合酵母单杂和ChIP等试验，证明了WRKY46可通过抑制位于液泡膜上的亚铁离子转运蛋白基因VITL1的表达，减少亚铁向液泡的转运，使进入植物细胞内的铁更多地转运到地上部分，满足地上部分对铁的需求。
原文链接：
A WRKY transcription factor regulates Fe translocation under Fe deficiency in ArABIdopsi
原文摘要：
Iron (Fe) deficiency affects plant growth and development, leading to reduction of crop yields and quality. Although the regulation of Fe uptake under Fe deficiency has been well studied in the past decade, the regulatory mechanism of Fe translocation inside the plants remains unknown. Here, we show that a WRKY transcription factor WRKY46 is involved in response to Fe deficiency. Lack of WRKY46 (wrky46-1 and wrky46-2 loss-of-function mutants) significantly affects Fe translocation from root to shoot, and thus causes obvious chlorosis on the new leaves under Fe deficiency. Gene expression analysis reveals that expression of a nodulin-like gene (Vacuolar Iron Transporter1-like1, VITL1) is dramatically increased in wrky46-1 mutant. VITL1 expression is inhibited by Fe deficiency, while the expression of WRKY46 is induced in the root stele. Moreover, downregulation of VITL1 expression can restore chlorosis phenotype on wrky46-1 under Fe deficiency. Further yeast-one-hybrid and ChIP experiments indicate that WRKY46 is capable of binding to the specific W-boxes present in the VITL1 promoter. In summary, our results demonstrate that WRKY46 plays an important role in the control of root-to-shoot Fe translocation under Fe-deficiency condition via direct regulation of VITL1 transcript levels.
作者：郑绍建
