Authors:
Henrike Würsig | Helmholtz Centre for Environmental Research – UFZ Halle, Germany | Germany
Bunlong Yim | Julius Kuehn-Institute (JKI), Federal Research Institute for Cultivated Plants, Braunschweig, Germany
Maria Martin Roldan | Helmholtz Centre for Environmental Research – UFZ Halle, Germany
Negar Ghaderi | Helmholtz Centre for Environmental Research – UFZ Halle, Germany
Marie-Lara Bouffaud | Helmholtz Centre for Environmental Research – UFZ Halle, Germany
Susanne Schreiter | Helmholtz Centre for Environmental Research – UFZ Halle, Germany
Eva Lippold | Helmholtz Centre for Environmental Research – UFZ Halle, Germany
Doris Vetterlein | Helmholtz Centre for Environmental Research – UFZ Halle, Germany
Evgenia Blagodatskaya | Helmholtz Centre for Environmental Research – UFZ Halle, Germany
Kornelia Smalla | Julius Kuehn-Institute (JKI), Federal Research Institute for Cultivated Plants, Braunschweig, Germany
Mika Tapio Tarkka | Helmholtz Centre for Environmental Research – UFZ Halle, Germany
Improved understanding of plant-soil-microbe interactions is mandatory for tackling problems in crop production that are caused by increased frequency and intensity of drought events. Due to drought-triggered alterations in root growth and exudation, plants can shape the rhizosphere microbiome and enzyme activities, which in turn can play out in the plant’s drought tolerance. To better understand how these feedback processes are affected by drought, root gene expression, rhizosphere microbial community composition and potential rhizosphere enzyme activities of maize plants, grown on the substrates sand and loam, were investigated during two dry and one moist year. Based on literature, we expected that drought periods stimulate root gene expression related to drought stress, lower rhizosphere enzyme activities, but higher relative abundancies of Actinobacteria. We also expect a higher substrate-effect in the dry years. Higher expression levels of genes encoding for dehydrins and heat shock proteins, as well as increased levels of malondialdehyde were found in the dry years, indicating a stress response. Surprisingly, these changes were accompanied by higher rhizosphere enzyme activities during the dry years. Alterations in microbial community composition were also detected, showing increased levels of Actinobacteria. The substrate-effect on root gene expression was stronger in the dry year, in contrast to the rhizosphere microbial community composition and enzyme activities. Our results show how maize roots and rhizospheres respond to dry and warm climate, and suggest that the rhizosphere microbiome contribute to this process. In a next step, we compare the nutrient transporter gene expression of loam and sand, expecting a stronger expression in sand in the dry years.