21 August 2019
Desert oasis date palms are selective about their bacteria
Published online 27 March 2019
Date palms growing in desert oases choose the soil bacteria they associate with.
The roots of date palms growing in distant Tunisian desert oases consistently recruit the same two types of growth-promoting bacteria from the soil, making the plant the key determining factor for the selection of growth-promoting microbes. This is in contrast to more homogenous, nutrient-rich agroecosystems, where the soil is the main factor determining the types of bacteria associated with plant roots.
The finding could be used to develop effective biofertilizers for date palms, says microbial ecologist Daniele Daffonchio from King Abdullah University of Science and Technology in Saudi Arabia. He and his colleagues analysed date palm roots and soil samples collected from seven oases located in a surface area of 22,200 km2 along the northern edge of the Tunisian Sahara Desert.
They sequenced the genes of the soil bacteria and found that the plant growth-promoting microbes most associated with the date palm roots belonged mainly to two phyla: Gammaproteobacteria and Alphaproteobacteria.
Despite differences in soil composition and location, the date palms consistently recruited similar bacterial communities. The plants released compounds into the soil, recruiting larger numbers of bacteria to the areas near their roots than those present in the surrounding bulk soil.
The research could help improve the sustainable production of date palms and other crops, according to co-author, Ramona Marasco. It could also be useful for restoring land currently undergoing desertification.
Mosqueira, M. J. et al. Consistent bacterial selection by date palm root system across heterogeneous desert oasis agroecosystems. Sci. Rep. 9:4033 (2019).