内生芽孢杆菌WR10促进小麦籽粒铁积累的分子机制

多种微生物可以环保高效地促进小麦富铁,为应对全球性膳食性缺铁这一营养问题提供了绿色方案。微生物富铁取决于其对小麦铁吸收、转运和积累三个连续过程的影响。其中促进籽粒铁积累是微生物富铁的瓶颈，但具体分子机制尚不清楚。我们分离的内生芽孢杆菌WR10可定殖籽粒，并显著提高包括周麦22在内的多种小麦的籽粒铁含量。因此，本项目拟以WR10和周麦22为研究对象，聚焦籽粒富铁关键期，全面揭示微生物促进小麦铁积累的分子机制。先比较不同时期的籽粒铁含量和WR10丰度以确定微生物促进铁积累的关键时期。其次通过比较转录组、基因沉默及突变体构建，确定关键期受WR10诱导的小麦铁效应基因以及WR10发挥富铁作用所必需的功能基因。最后，通过研究WR10表面功能蛋白IlsA与小麦效应蛋白Ferritin的相互作用，分析它们调控铁积累的机制。本项目从微生物-植物互作角度阐明微生物富铁的分子基础，为其高效应用提供理论支撑。

Versatile microbes can improve iron concentrations in wheat grain by an environment-friend way, which provided a green strategy to combat dietary iron deficiency, one of the global nutrition problems. Grain iron concentrations were affected by microbes through interfering three consecutive processes, including the uptake, translocation or remobilization, and accumulation. Among them, iron accumulation process is the bottleneck during iron biofortification. Mechanism behind this process after inoculation of microbes is unknown. One of our isolate, Bacillus altitudinis WR10 colonized the seed, significantly improved grain iron content in several wheat lines including Zhoumai 22. The current project aims at revealing the molecular mechanisms of iron accumulation during the key growth phase of wheat when microbes were applied for improving iron biofortification, using B. altitudinis WR10 and Zhoumai 22 as subjects. At first, the key growth phase was determined by detecting iron content and quantifying WR10 abundance within the five sub-stages. Secondly, we summarize those differently expressed genes (DEGs) in both bacteria and wheat by comparative transcriptomics at above determined stage. Iron related functions of some DEGs will be validated by interfering or silencing their expression in wheat, or constructing mutants of WR10. At last, we plan to investigate the binding of one surface protein IlsA in WR10 to the main iron storage protein Ferritin in wheat. The role of IlsA for regulating iron accumulation will be also analyzed. The project tries to provide a mechanical support for efficient utilization of agricultural microbes, and will lay a foundation for its efficient application, from a perspective of microbe-plant interaction.