Prospecting endophytes from different Fe or Zn accumulating wheat genotypes for their influence as inoculants on plant growth, yield, and micronutrient content

Abstract

The plant microbiome is known to play a significant role in improving plant productivity and quality of produce, and the endophytic component was explored toward developing inoculants for enhancing micronutrient concentration in grains. A set of 213 endophytes (201 bacteria and 12 fungi) were isolated, from a set of 13 wheat genotypes, identified through preliminary screening as low and high iron and zinc accumulating genotypes. A pot experiment, with two low accumulator genotypes and eight selected endophytes, was undertaken, followed by field evaluation with both high and low Zn or Fe accumulator genotypes. Screening of these endophytes identified 11 bacteria and 2 fungi as being efficient for zinc solubilization, while 10 bacteria and 2 fungi were promising siderophore producers. Zinc and iron uptake were enhanced by one to several folds over the recommended dose of NPK (RDF) in the pot experiment. Two sets of promising endophytes, identified as Bacillus subtilis (DS-178) and Arthrobacter sp. (DS-179) for zinc accumulation, and Arthrobacter sulfonivorans (DS-68) and Enterococcus hirae (DS-163) for iron acquisition in grains, were selected. Significant increase of 14–20% in plant growth and yield was recorded in field experiment, with 75% increase, over RDF, in terms of Fe or Zn accumulation in wheat grains. Phytic acid, an anti-nutritional factor, was significantly lower in grains from endophyte inoculated treatments in the wheat genotypes evaluated. This illustrated the promise of these endophytes in improving both the translocation of micronutrients and enhancing the quality of wheat grains.