Enhancing grain iron content of rice by the application of plant growth promoting rhizobacteria

Rice is inherently low in micronutrients, especially iron, which leads to severe malnutrition problems in rice-consuming populations. Different plant growth promoting rhizobacterial strains (PGPRs) (viz. Pseudomonas putida, Pseudomonas fluorescens, and Azospirillum lipoferum from a microbial collection and B 15, B 17, B 19, BN 17 and BN 30 isolated from the rhizospheric soils) were applied to field grown rice plants with an aim to increase the iron content of grains. 16S rRNA gene sequence showed that isolates belong to Enterobacteria species. Different parameters related to the increase in iron content of plants show an enhancement upon treatment of rice plants with PGPRs. Treatments with P. putida, B 17 and B 19 almost doubled the grain iron content. Besides this, the translocation efficiency of the iron from roots to shoots to grains was also enhanced upon treatment with PGPRs. It is therefore concluded that application of PGPR strains is an important strategy to combat the problem of iron deficiency in rice and consecutively in human masses.