Biology subjects

Brawner, J. T.

Publications and source records attributed to Brawner, J. T..

2 recordsLinked to original sources

bioRxiv2023

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

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

plant biology↗

bioRxiv2022

Genome-wide identification, characterization, and comparative analysis of NLR resistance genes in Coffea spp.

The largest family of disease resistance genes in plants are nucleotide-binding site leucine-rich repeat genes (NLRs). The products of these genes are responsible for recognizing avirulence proteins (Avr) of phytopathogens and triggering specific defense responses. Identifying NLRs in plant genomes with standard gene annotation software is challenging due to their multidomain nature, sequence diversity, and clustered genomic distribution. We present the results of a genome-wide scan and comparative analysis of NLR loci in three coffee species (Coffea canephora, Coffea eugenioides and their interspecific hybrid Coffea arabica). A total of 1311 non-redundant NLR loci were identified in C. arabica, 927 in C. canephora, and 1079 in C. eugenioides, of which 809, 562, and 695 are complete loci, respectively. The NLR-annotator tool used in this study showed extremely high sensitivities and specificities (over 99%) and increased the detection of putative NLRs in the reference coffee genomes. The NLRs loci in coffee are distributed among all chromosomes and are organized mostly in clusters. The C. arabica genome presented a smaller number of NLR loci when compared to the sum of the parental genomes (C. canephora, and C. eugenioides). There are orthologous NLRs (orthogroups) shared between coffee, tomato, potato, and reference NLRs and those that are shared only among coffee species, which provides clues about the functionality and evolutionary history of these orthogroups. Phylogenetic analysis demonstrated orthologous NLRs shared between C. arabica and the parental genomes and those that were possibly lost. The NLR family members in coffee are subdivided into two main groups: TIR-NLR (TNL) and non-TNL. The non-TNLs seem to represent a repertoire of resistance genes that are important in coffee. These results will support functional studies and contribute to a more precise use of these genes for breeding disease-resistant coffee cultivars.

plant biology↗