IAA producing Bacillus altitudinis alleviates iron stress in Triticum aestivum L. seedling by both bioleaching of iron and up-regulation of genes encoding ferritins

• DOI: 10.1007/s11104-017-3218-9
• Publication Date: 2017-03-13T08:49:38Z
• Authors: Zhongke Sun; Kun Liu; Ju Zhang; Yi Zhang; Kedong Xu; Deshui Yu; Jian Wang; Lizong Hu; Long Chen; Chengwei Li
• Keywords: Plant Physiology

Many microbes are beneficial to plants and are termed as plant growth promoting bacteria (PGPB). This study explores the effect and mechanism of endophytic bacteria on wheat iron stress. Bacteria and wheat seedlings were hydroponically co-cultured under different concentrations of iron. Growth parameters were measured and transcriptions of ferritins as well as transporters were quantified by real-time quantitative PCR. An endophytic Bacillus altitudinis WR10 was isolated from the root of Triticum aestivum L. The strain is resistant to 5 mM iron and it bioleaches more than 80% iron after 24 h of incubation. Meanwhile, WR10 produces as much as 35pM indole 3 acetic acid (IAA) during fermentation but there was no accumulation of cytokinin (zeatin to be precise). Inoculation of WR10 significantly improves the growth of the primary root and main sprout in wheat seedlings in a co-culture model under iron stress after two weeks hydroponic cultivation. The presence of WR10 up-regulates the expression of many genes encoding ferritins in wheat roots under iron stress. Besides its ability to bioleach iron, IAA producing B. altitudinis WR10 can alleviate iron stress in wheat by up-regulation of ferritin-encoded genes in roots, which is important for maintaining iron homeostasis.