Dataset Information

Core and Differentially Abundant Bacterial Taxa in the Rhizosphere of Field Grown Brassica napus Genotypes: Implications for Canola Breeding.

ABSTRACT: Modifying the rhizosphere microbiome through targeted plant breeding is key to harnessing positive plant-microbial interrelationships in cropping agroecosystems. Here, we examine the composition of rhizosphere bacterial communities of diverse Brassica napus genotypes to identify: (1) taxa that preferentially associate with genotypes, (2) core bacterial microbiota associated with B. napus, (3) heritable alpha diversity measures at flowering and whole growing season, and (4) correlation between microbial and plant genetic distance among canola genotypes at different growth stages. Our aim is to identify and describe signature microbiota with potential positive benefits that could be integrated in B. napus breeding and management strategies. Rhizosphere soils of 16 diverse genotypes sampled weekly over a 10-week period at single location as well as at three time points at two additional locations were analyzed using 16S rRNA gene amplicon sequencing. The B. napus rhizosphere microbiome was characterized by diverse bacterial communities with 32 named bacterial phyla. The most abundant phyla were Proteobacteria, Actinobacteria, and Acidobacteria. Overall microbial and plant genetic distances were highly correlated (R = 0.65). Alpha diversity heritability estimates were between 0.16 and 0.41 when evaluated across growth stage and between 0.24 and 0.59 at flowering. Compared with a reference B. napus genotype, a total of 81 genera were significantly more abundant and 71 were significantly less abundant in at least one B. napus genotype out of the total 558 bacterial genera. Most differentially abundant genera were Proteobacteria and Actinobacteria followed by Bacteroidetes and Firmicutes. Here, we also show that B. napus genotypes select an overall core bacterial microbiome with growth-stage-related patterns as to how taxa joined the core membership. In addition, we report that sets of B. napus core taxa were consistent across our three sites and 2 years. Both differential abundance and core analysis implicate numerous bacteria that have been reported to have beneficial effects on plant growth including disease suppression, antifungal properties, and plant growth promotion. Using a multi-site year, temporally intensive field sampling approach, we showed that small plant genetic differences cause predictable changes in canola microbiome and are potential target for direct and indirect selection within breeding programs.

SUBMITTER: Taye ZM

PROVIDER: S-EPMC6974584 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Core and Differentially Abundant Bacterial Taxa in the Rhizosphere of Field Grown Brassica napus Genotypes: Implications for Canola Breeding.

Taye Zelalem M ZM Helgason Bobbi L BL Bell Jennifer K JK Norris Charlotte E CE Vail Sally S Robinson Stephen J SJ Parkin Isobel A P IAP Arcand Melissa M Mamet Steven S Links Matthew G MG Dowhy Tanner T Siciliano Steven S Lamb Eric G EG

Frontiers in microbiology 20200115

Modifying the rhizosphere microbiome through targeted plant breeding is key to harnessing positive plant-microbial interrelationships in cropping agroecosystems. Here, we examine the composition of rhizosphere bacterial communities of diverse Brassica napus genotypes to identify: (1) taxa that preferentially associate with genotypes, (2) core bacterial microbiota associated with B. napus, (3) heritable alpha diversity measures at flowering and whole growing season, and (4) correlat ...[more]

PMID: 32010086

Similar Datasets

Project description:Genomic selection (GS) is a modern breeding approach where genome-wide single-nucleotide polymorphism (SNP) marker profiles are simultaneously used to estimate performance of untested genotypes. In this study, the potential of genomic selection methods to predict testcross performance for hybrid canola breeding was applied for various agronomic traits based on genome-wide marker profiles. A total of 475 genetically diverse spring-type canola pollinator lines were genotyped at 24,403 single-copy, genome-wide SNP loci. In parallel, the 950 F1 testcross combinations between the pollinators and two representative testers were evaluated for a number of important agronomic traits including seedling emergence, days to flowering, lodging, oil yield and seed yield along with essential seed quality characters including seed oil content and seed glucosinolate content. A ridge-regression best linear unbiased prediction (RR-BLUP) model was applied in combination with 500 cross-validations for each trait to predict testcross performance, both across the whole population as well as within individual subpopulations or clusters, based solely on SNP profiles. Subpopulations were determined using multidimensional scaling and K-means clustering. Genomic prediction accuracy across the whole population was highest for seed oil content (0.81) followed by oil yield (0.75) and lowest for seedling emergence (0.29). For seed yieId, seed glucosinolate, lodging resistance and days to onset of flowering (DTF), prediction accuracies were 0.45, 0.61, 0.39 and 0.56, respectively. Prediction accuracies could be increased for some traits by treating subpopulations separately; a strategy which only led to moderate improvements for some traits with low heritability, like seedling emergence. No useful or consistent increase in accuracy was obtained by inclusion of a population substructure covariate in the model. Testcross performance prediction using genome-wide SNP markers shows considerable potential for pre-selection of promising hybrid combinations prior to resource-intensive field testing over multiple locations and years.

Project description:Salinity is one of the major abiotic stresses prevailing throughout the world that severely limits crop establishment and production. Every crop has an intra-specific genetic variation that enables it to cope with variable environmental conditions. Hence, this genetic variability is a good tool to exploit germplasms in salt-affected areas. Further, the selected cultivars can be effectively used by plant breeders and molecular biologists for the improvement of salinity tolerance. In the present study, it was planned to identify differential expression of genes associated with selective uptake of different ions under salt stress in selected salt-tolerant canola (Brassica napus L.) cultivar. For the purpose, an experiment was carried out to evaluate the growth response of different salt-sensitive and salt-tolerant canola cultivars. Plants were subjected to 200 mM NaCl stress. Canola cultivars-Faisal Canola, DGL, Dunkled, and CON-II-had higher growth than in cvs Cyclone, Ac-EXcel, Legend, and Oscar. Salt-tolerant cultivars were better able to maintain plant water status probably through osmotic adjustment as compared to salt-sensitive cultivars. Although salt stress increased shoot Na+ and shoot Cl- contents in all canola cultivars, salt-tolerant cultivars had a lower accumulation of these toxic nutrients. Similarly, salt stress reduced shoot K+ and Ca2+ contents in all canola cultivars, while salt-tolerant cultivars had a higher accumulation of K+ and Ca2+ in leaves, thereby having greater shoot K+/Na+ and Ca2+/Na+ ratios. Nutrient utilization efficiency decreased significantly in all canola cultivars due to the imposition of salt stress; however, it was greater in salt-tolerant cultivars-Faisal Canola, DGL, and Dunkled. Among four salt-tolerant canola cultivars, cv Dunkled was maximal in physiological attributes, and thus differentially expressed genes (DEGs) were assessed in it by RNA-seq analysis using next-generation sequencing (NGS) techniques. The differentially expressed genes (DEG) in cv Dunkled under salt stress were found to be involved in the regulation of ionic concentration, photosynthesis, antioxidants, and hormonal metabolism. However, the most prominent upregulated DEGs included Na/K transporter, HKT1, potassium transporter, potassium channel, chloride channel, cation exchanger, Ca channel. The RNA-seq data were validated through qRT-PCR. It was thus concluded that genes related to the regulation of ionic concentrate are significantly upregulated and expressed under salt stress, in the cultivar Dunkled.

Project description:BackgroundEukaryotic mitogen-activated protein kinase (MAPK/MPK) signaling cascades transduce and amplify environmental signals via three types of reversibly phosphorylated kinases to activate defense gene expression. Canola (oilseed rape, Brassica napus) is a major crop in temperate regions. Identification and characterization of MAPK and MAPK kinases (MAPKK/MKK) of canola will help to elucidate their role in responses to abiotic and biotic stresses.ResultsWe describe the identification and analysis of seven MKK (BnaMKK) and 12 MPK (BnaMPK) members from canola. Sequence alignments and phylogenetic analyses of the predicted amino acid sequences of BnaMKKs and BnaMPKs classified them into four different groups. We also examined the subcellular localization of four and two members of BnaMKK and BnaMPK gene families, respectively, using green fluorescent protein (GFP) and, found GFP signals in both nuclei and cytoplasm. Furthermore, we identified several interesting interaction pairs through yeast two-hybrid (Y2H) analysis of interactions between BnaMKKs and BnaMPKs, as well as BnaMPK and BnaWRKYs. We defined contiguous signaling modules including BnaMKK9-BnaMPK1/2-BnaWRKY53, BnaMKK2/4/5-BnaMPK3/6-BnaWRKY20/26 and BnaMKK9-BnaMPK5/9/19/20. Of these, several interactions had not been previously described in any species. Selected interactions were validated in vivo by a bimolecular fluorescence complementation (BiFC) assay. Transcriptional responses of a subset of canola MKK and MPK genes to stimuli including fungal pathogens, hormones and abiotic stress treatments were analyzed through real-time RT-PCR and we identified a few of BnaMKKs and BnaMPKs responding to salicylic acid (SA), oxalic acid (OA), Sclerotinia sclerotiorum or other stress conditions. Comparisons of expression patterns of putative orthologs in canola and Arabidopsis showed that transcript expression patterns were generally conserved, with some differences suggestive of sub-functionalization.ConclusionsWe identified seven MKK and 12 MPK genes from canola and examined their phylogenetic relationships, transcript expression patterns, subcellular localization, and protein-protein interactions. Not all expression patterns and interactions were conserved between canola and Arabidopsis, highlighting the limitations of drawing inferences about crops from model species. The data presented here provide the first systematic description of MKK-MPK-WRKY signaling modules in canola and will further improve our understanding of defense responses in general and provide a basis for future crop improvement.

Dataset Information

Core and Differentially Abundant Bacterial Taxa in the Rhizosphere of Field Grown Brassica napus Genotypes: Implications for Canola Breeding.

Publications

Core and Differentially Abundant Bacterial Taxa in the Rhizosphere of Field Grown <i>Brassica napus</i> Genotypes: Implications for Canola Breeding.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets