Soil chemical properties affect the reaction of forest soil bacteria to drought and rewetting stress.
Reaction of soil bacteria to drought and rewetting stress may depend on soil chemical properties. The objectives of this study were to test the reaction of different bacterial phyla to drought and rewetting stress and to assess the influence of different soil chemical properties on the reaction of soil bacteria to this kind of stress. The soil samples were taken at ten forest sites and measured for pH and the contents of organic C (Corg) and total N (Nt), Zn, Cu, and Pb. The samples were kept without water addition at 20 - 30 °C for 8 weeks and subsequently rewetted to achieve moisture equal to 50 - 60 % of their maximum water-holding capacity. Prior to the drought period and 24 h after the rewetting, the structure of soil bacterial communities was determined using pyrosequencing of 16S rRNA genes. The drought and rewetting stress altered bacterial community structure. Gram-positive bacterial phyla,ActinobacteriaandFirmicutes, increased in relative proportion after the stress, whereas the Gram-negative bacteria in most cases decreased. The largest decrease in relative abundance was forGammaproteobacteriaandBacteroidetes. For several phyla the reaction to drought and rewetting stress depended on the chemical properties of soils. Soil pH was the most important soil property influencing the reaction of a number of soil bacterial groups (including all classes ofProteobacteria,Bacteroidetes,Acidobacteria, and others) to drought and rewetting stress. For several bacterial phyla the reaction to the stress depended also on the contents of Ntand Corgin soil. The effect of heavy metal pollution was also noticeable, although weaker compared to other chemical soil properties. We conclude that soil chemical properties should be considered when assessing the effect of stressing factors on soil bacterial communities.
Department of Management and Protection of Environment, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland.
Marcin
M
Chodak
Department of Biotechnology, Nicolaus Copernicus University, ul. Gagarina 9, 87-100 Toruń, Poland.
Marcin
M
Gołębiewski
Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
Justyna
J
Morawska-Płoskonka
Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
Katarzyna
K
Kuduk
Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
Maria
M
Niklińska
Bacterial phyla; Drought and rewetting stress; Forest soils; Pyrosequencing; Soil chemical properties