Endophytes from the crop wild relative Hordeum secalinum L. improve agronomic traits in unstressed and salt-stressed barley

Abstract

Agricultural crops growing in saline soils produce sub-optimal yields due to the negative effects of excess salts on plant growth and development. Salinity stress for crops is likely to increase as a result of climate change and the consequent salinisation of soils, particularly in coastal areas. In this study, we recovered fungal endophytes from the seeds of the wild barley relative Hordeum secalinum and tested their effects on a barley cultivar grown in a controlled environment under four levels of continuously applied salt stress: 0, 75, 150 and 250 mM NaCl. For the unstressed plants and plants stressed with 75 mM NaCl we found an endophyte-associated increase in early growth, grain dry weight, shoot dry weight, root dry weight, number of tillers, number of heads and number of grains. However, this relationship was reversed for the plants grown with 150 and 250 mM NaCl, where the endophytes negatively affected these traits. Plants stressed with the highest concentration of NaCl (250 mM) produced no grain. These results suggest that the endophytes may have potential to benefit field grown barley crops growing on moderately salt-stressed sites.