Assessing the impact of successive soil cultivation on Meloidogyne enterolobii infection and on soil bacterial assemblages

Abstract

Soil cultivation may change the soil microbiome and alter interactions between plants and parasites. The objective of this work was to evaluate temporal changes in plant health, microbiome abundance, bacterial diversity and the plant-parasitic nematode, Meloidogyne enterolobii incidence in two soil fields with different agricultural uses. Soil samples were collected from a commercial tomato production field (agricultural soil) and a single-cultivation strawberry field (native soil). Samples for the second experiment were collected from the same fields the following year. Tomato plants cv. Yearly Girl were grown in a greenhouse and inoculated with M. enterolobii. After 45 days, plants were evaluated for the plant growth parameters, nematode reproduction, and soil bacterial assemblages were assessed using cultivation-independent sequencing methods (V3/V4 region of the rRNA 16S). Overall the average of fruit fresh weight in the second experiment was 2.4-fold to 14-fold higher than the first experiment. Moreover, there was a 80.5% decrease in eggs present per root system from the first experiment to the second. The relative abundance of bacterial assemblages from Experiment 1 to Experiment 2 changed for most of the top phyla (eg. Actinobacteria, Bacteroidetes, and Chloroflexi) and genera (eg. Bacillus, Streptomyces, and Flavisolibacter) and there was no change in microbial diversity between the two experiments. This study suggests that soil management can lead to an overall decrease in nematode reproduction and better crop yield, as well as a shift in the overall bacterial assemblages. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/525929v1_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@2b76b2org.highwire.dtl.DTLVardef@17db6c5org.highwire.dtl.DTLVardef@6a6d69org.highwire.dtl.DTLVardef@1352fb0_HPS_FORMAT_FIGEXP M_FIG C_FIG