scholarly journals Analysis of leaf microbiome composition of near-isogenic maize lines differing in broad-spectrum disease resistance

2019 ◽  
Author(s):  
Maggie R. Wagner ◽  
Posy E. Busby ◽  
Peter Balint-Kurti
Keyword(s):  
Disease Resistance ◽  
Broad Spectrum ◽  
Fungal Pathogens ◽  
List Type ◽  
Plant Genotype ◽  
Susceptible Parent ◽  
Host Genotype ◽  
Microbiome Composition ◽  
Resistant Lines ◽  
Disease Pressure

SummaryPlant genotype strongly affects disease resistance, and also influences the composition of the leaf microbiome. However, these processes have not been studied and linked in the microevolutionary context of breeding for improved disease resistance. We hypothesized that broad-spectrum disease resistance alleles also affect colonization by non-pathogenic symbionts.Quantitative trait loci (QTL) conferring resistance to multiple fungal pathogens were introgressed into a disease-susceptible maize inbred line. Bacterial and fungal leaf microbiomes of the resulting near-isogenic lines were compared to the microbiome of the disease-susceptible parent line at two timepoints in multiple fields.Introgression of QTL from disease-resistant lines strongly shifted the relative abundance of diverse fungal and bacterial taxa in both 3-week-old and 7-week-old plants. Nevertheless, the effects on overall community structure and diversity were minor and varied among fields and years. Contrary to our expectations, host genotype effects were not any stronger in fields with high disease pressure than in uninfected fields, and microbiome succession over time was similar in heavily infected plants and uninfected plants.These results show that introgressed QTL can greatly improve broad-spectrum disease resistance while having only limited and inconsistent pleiotropic effects on the leaf microbiome in maize.

scholarly journals Host-generalist fungal pathogens of seedlings may maintain forest diversity via host-specific impacts and differential susceptibility among tree species

2020 ◽  
Author(s):  
Erin R. Spear ◽  
Kirk Broders
Keyword(s):  
Tree Species ◽  
Fungal Pathogens ◽  
Phylogenetic Signal ◽  
Differential Susceptibility ◽  
Host Use ◽  
List Type ◽  
Disease Symptoms ◽  
Forest Diversity ◽  
Relative Rarity ◽  
Disease Pressure

SummaryHost-specialized pathogens are credited with the maintenance of tropical forest diversity under the Janzen-Connell hypothesis (JCH). Yet, in diverse forests, selection should favor pathogens with broad host ranges given their passive dispersal and the relative rarity of tree species.We surveyed the host associations of potential pathogens isolated from symptomatic seedlings in the forests in Panama; and used inoculations to assess the pathogenicity and host ranges of 27 fungal isolates, and (ii) differences among tree species in susceptibility.Thirty-one of the 33 non-singleton OTUs isolated from seedlings are multi-host. All 31 multi-host OTUs exhibit low to moderate specialization and phylogenetically dispersed host use, with no phylogenetic signal. The pathogenicity of 10 isolates was experimentally confirmed; nine caused disease in seedlings in multiple families. However, the outcome of infection differs among tree species susceptible to a given multi-host pathogen. Furthermore, some tree species were seemingly resistant to all fungi tested, while others were susceptible to multiple fungi. Tree species adapted to environments with lower disease pressure were most likely to exhibit disease symptoms.Our results suggest that generalist pathogens contribute to the maintenance of local forest diversity via host-specific impacts rather than the host specificity originally envisioned under JCH.

scholarly journals Heterosis of leaf and rhizosphere microbiomes in field-grown maize

2020 ◽  
Author(s):  
Maggie R. Wagner ◽  
Joe H. Roberts ◽  
Peter Balint-Kurti ◽  
James B. Holland
Keyword(s):  
Complex Traits ◽  
Molecular Mechanisms ◽  
Amplicon Sequencing ◽  
Inbred Lines ◽  
List Type ◽  
Host Genotype ◽  
Narrow Sense Heritability ◽  
Microbiome Composition ◽  
Wide Range ◽  
Microbial Symbionts

SummaryMacroorganisms’ genotypes shape their phenotypes, which in turn shape the habitat available to potential microbial symbionts. This influence of host genotype on microbiome composition has been demonstrated in many systems; however, most previous studies have either compared unrelated genotypes or delved into molecular mechanisms. As a result, it is currently unclear whether the heritability of host-associated microbiomes follows similar patterns to the heritability of other complex traits.We take a new approach to this question by comparing the microbiomes of diverse maize inbred lines and their F1 hybrid offspring, which we quantified in both rhizosphere and leaves of field-grown plants using 16S-v4 and ITS1 amplicon sequencing.We show that inbred lines and hybrids differ consistently in composition of bacterial and fungal rhizosphere communities, as well as leaf-associated fungal communities. A wide range of microbiome features display heterosis within individual crosses, consistent with patterns for non-microbial maize phenotypes. For leaf microbiomes, these results were supported by the observation that broad-sense heritability in hybrids was substantially higher than narrow-sense heritability.Our results support our hypothesis that at least some heterotic host traits affect microbiome composition in maize.

scholarly journals Analysis of leaf microbiome composition of near‐isogenic maize lines differing in broad‐spectrum disease resistance

2019 ◽  
Vol 225 (5) ◽  
pp. 2152-2165 ◽  
Author(s):  
Maggie R. Wagner ◽  
Posy E. Busby ◽  
Peter Balint‐Kurti
Keyword(s):  
Disease Resistance ◽  
Broad Spectrum ◽  
Microbiome Composition

Comparative Mapping of Three Bacterial, Three Fungal, and One Virus Disease-resistance Genes in Common Bean

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 547a-547
Author(s):  
Geunhwa Jung ◽  
James Nienhuis ◽  
Dermot P. Coyne ◽  
H.M. Ariyarathne
Keyword(s):  
Disease Resistance ◽  
Common Bean ◽  
Pseudomonas Syringae ◽  
Resistance Genes ◽  
Fungal Pathogens ◽  
Xanthomonas Campestris ◽  
Virus Disease ◽  
Disease Resistance Genes ◽  
Brown Spot ◽  
Viral Pathogen

Common bacterial blight (CBB), bacterial brown spot (BBS), and halo blight (HB), incited by the bacterial pathogens Xanthomonas campestris pv. phaseoli (Smith) Dye, Pseodomonas syringae pv. syringa, and Pseudomonas syringae pv. phaseolicola, respectively are important diseases of common bean. In addition three fungal pathogens, web blight (WB) Thanatephorus cucumeris, rust Uromyces appendiculatus, and white mold (WM) Sclerotinia sclerotiorum, are also destructive diseases attacking common bean. Bean common mosaic virus is also one of most major virus disease. Resistance genes (QTLs and major genes) to three bacterial (CBB, BBS, and HB), three fungal (WB, rust, and WM), and one viral pathogen (BCMV) were previously mapped in two common bean populations (BAC 6 × HT 7719 and Belneb RR-1 × A55). The objective of this research was to use an integrated RAPD map of the two populations to compare the positions and effect of resistance QTL in common bean. Results indicate that two chromosomal regions associated with QTL for CBB resistance mapped in both populations. The same chromosomal regions associated with QTL for disease resistance to different pathogens or same pathogens were detected in the integrated population.

scholarly journals Chickpea shows genotype-specific nodulation responses across soil nitrogen environment and root disease resistance categories

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Krista L. Plett ◽  
Sean L. Bithell ◽  
Adrian Dando ◽  
Jonathan M. Plett
Keyword(s):  
Nitrogen Fixation ◽  
Disease Resistance ◽  
Soil Nitrogen ◽  
Cellular Localization ◽  
Expression Patterns ◽  
Nodule Development ◽  
Nodule Formation ◽  
Symbiotic Relationship ◽  
Plant Genotype ◽  
Factors Affecting

Abstract Background The ability of chickpea to obtain sufficient nitrogen via its symbiotic relationship with Mesorhizobium ciceri is of critical importance in supporting growth and grain production. A number of factors can affect this symbiotic relationship including abiotic conditions, plant genotype, and disruptions to host signalling/perception networks. In order to support improved nodule formation in chickpea, we investigated how plant genotype and soil nutrient availability affect chickpea nodule formation and nitrogen fixation. Further, using transcriptomic profiling, we sought to identify gene expression patterns that characterize highly nodulated genotypes. Results A study involving six chickpea varieties demonstrated large genotype by soil nitrogen interaction effects on nodulation and further identified agronomic traits of genotypes (such as shoot weight) associated with high nodulation. We broadened our scope to consider 29 varieties and breeding lines to examine the relationship between soilborne disease resistance and the number of nodules developed and real-time nitrogen fixation. Results of this larger study supported the earlier genotype specific findings, however, disease resistance did not explain differences in nodulation across genotypes. Transcriptional profiling of six chickpea genotypes indicates that genes associated with signalling, N transport and cellular localization, as opposed to genes associated with the classical nodulation pathway, are more likely to predict whether a given genotype will exhibit high levels of nodule formation. Conclusions This research identified a number of key abiotic and genetic factors affecting chickpea nodule development and nitrogen fixation. These findings indicate that an improved understanding of genotype-specific factors affecting chickpea nodule induction and function are key research areas necessary to improving the benefits of rhizobial symbiosis in chickpea.

THE INHERITANCE OF RESISTANCE IN RYE TO Puccinia recondita f. sp. secalis and f. sp. tritici

1984 ◽  
Vol 64 (3) ◽  
pp. 511-519 ◽  
Author(s):  
G. L. C. MUSA ◽  
P. L. DYCK ◽  
D. J. SAMBORSKI
Keyword(s):  
Disease Resistance ◽  
Leaf Rust ◽  
Secale Cereale ◽  
Single Gene ◽  
Inbred Lines ◽  
Puccinia Recondita ◽  
Wheat Leaf Rust ◽  
Susceptible Parent ◽  
Seedling Resistance ◽  
Wheat Leaf

The inheritance of seedling resistance to isolate RLR 213/78 of rye leaf rust (Puccinia recondita f. sp. secalis) and race 30 of wheat leaf rust (P. recondita f. sp. tritici Rob.) was investigated in six inbred lines of rye (Secale cereale). Inbred line UM8116 was used as the susceptible parent in crosses. Inbred lines UM8003, UM8071 and UM8301 each have a single gene and UM8336 and UM8340 each have two genes for resistance to rye leaf rust. For resistance to wheat leaf rust UM8071 has a single gene, UM8003 and UM8340 each have two genes and UM8301 and UM8336 each have three genes. UM8295 is heterogeneous for reaction to both rusts. One of the genes in UM8340 may condition resistance to both rusts. The genes for resistance to RLR 213/78 appear to be independently inherited while some of the genes conferring resistance to race 30 may be identical or very closely linked. The potential of rye as a source of disease resistance for wheat and triticale improvement is discussed.Key words: Secale cereale, disease resistance, wheat leaf rust

scholarly journals An Atypical Kinase under Balancing Selection Confers Broad-Spectrum Disease Resistance in Arabidopsis

PLoS Genetics ◽  
2013 ◽  
Vol 9 (9) ◽  
pp. e1003766 ◽  
Author(s):  
Carine Huard-Chauveau ◽  
Laure Perchepied ◽  
Marilyne Debieu ◽  
Susana Rivas ◽  
Thomas Kroj ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Broad Spectrum ◽  
Balancing Selection

scholarly journals Level of Endogenous Jasmonate is Critical for Durable Broad-Spectrum Disease Resistance Against Rice Blast in a Japonica Rice Variety, Ziyu44

2021 ◽  
Author(s):  
Xingyu An ◽  
Hui Zhang ◽  
Jinlu Li ◽  
Rui Yang ◽  
Qianchun Zeng ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Signaling Pathway ◽  
Broad Spectrum ◽  
Rice Blast ◽  
Blast Resistance ◽  
Rice Variety ◽  
Blast Disease ◽  
Japonica Rice ◽  
Mycelium Growth ◽  
Broad Spectrum Resistance

Abstract Background: The molecular mechanism of durable and broad-spectrum resistance to rice blast disease in japonica rice variety is still very little known. Ziyu44, a local japonica rice variety in Yunnan Province of China, has shown durable broad-spectrum blast resistance for more than 30 years, and provides an opportunity for us to explore the molecular basis of broad-spectrum resistance to rice blast in japonica rice variety.Methods and Results: We conducted a comparative study of mycelium growth, aposporium formation, the accumulation of salicylate(SA), jasmonate(JA) and H2O2, the expression of SA- and JA-associated genes between Ziyu44 and susceptible variety Jiangnanxiangnuo (JNXN) upon M. oryzae infection. We found that appressorium formation and invasive hyphae extention were greatly inhibited in Ziyu 44 leaves compared with that in JNXN leaves. Both Ziyu 44 and JNXN plants maintained high levels of baseline SA and did not show increased accumulation of SA after inoculation with M. oryzae, while the levels of baseline JA in Ziyu 44 and JNXN plants were relatively low, and the accumulation of JA exhibited markedly increased in Ziyu 44 plants upon M. oryzae infection. The expression levels of key genes involving JA and SA signaling pathway OsCOI1b, OsNPR1, OsMPK6 as well as pathogenesis-related (PR) genes OsPR1a, OsPR1b and OsPBZ1, were markedly up-regulated in Ziyu44. Conclusions: The level of endogenous JA is critical for synchronous activation of SA and JA signaling pathway, up-regulating PR gene expression and enhancing disease resistance against rice blast in Ziyu44.

scholarly journals STRUCTURE AND FUNCTION OF THE FRUIT MICROBIOME IN HEALTHY AND DISEASED KIWIFRUIT

2019 ◽  
Vol 56 (03) ◽  
pp. 577-585
Author(s):  
Wenneng Wu
Keyword(s):  
Microbial Diversity ◽  
Relative Abundance ◽  
Foodborne Pathogens ◽  
Fungal Pathogens ◽  
Sugar Metabolism ◽  
Amino Sugar ◽  
Disease Diagnosis ◽  
Postharvest Disease ◽  
Pathogen Infection ◽  
Microbiome Composition

The fruit surface is an infection court where foodborne pathogens compete with indigenous microbiota for microsites to invade the fruits for nutrients acquisition. However, our current understanding of the structure and functions of fruit microbiome visa-vis postharvest pathogen infection is still nascent. Here, we sequenced the metagenomic DNA to understand the structural and functional attributes of healthy and diseased kiwifruit microbiome. The healthy fruits exhibited higher microbial diversity and distinct microbiome composition compared with diseased fruits. The microbiome of diseased fruit was dominated by fungal pathogens Neofusicoccum parvum and Diplodiaseriata, while the microbiome of healthy fruits were enriched by bacteria from Methylobacteriaceae, Sphingomonadaceae, Nocardioidaceae and fungi in Pleosporaceae. Importantly, the healthy fruit microbiome had a higher relative abundance of genes related to ABC transporter, two-component system, bacterial chemotaxis, bacterial secretion system, but had a lower relative abundance of genes associated with polycyclic aromatic hydrocarbon degradation, amino sugar and nucleotide sugar metabolism, glycine, serine and threonine metabolism compared with diseased fruits. Our results indicate that pathogen infection disrupts the fruit microbiome. The changes in microbiome composition and functions could also increase the possibility of secondary pathogen infection as the reduced microbial diversity may demonstrate less resistance to pathogens infection. Therefore, monitoring the microbiome dynamics and their functions using metagenomic approaches could be useful to build a predictive understanding of accurate postharvest disease diagnosis and management in the future

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