scholarly journals Characterizing and Mapping Resistance in Synthetic-Derived Wheat to Rhizoctonia Root Rot in a Green Bridge Environment

2016 ◽  
Vol 106 (10) ◽  
pp. 1170-1176 ◽  
Author(s):  
A. K. Mahoney ◽  
E. M. Babiker ◽  
T. C. Paulitz ◽  
D. See ◽  
P. A. Okubara ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Root Rot ◽  
Recombinant Inbred Lines ◽  
Genetic Resistance ◽  
Genotyping By Sequencing ◽  
Interval Mapping ◽  
Environmentally Sustainable ◽  
Soilborne Disease ◽  
Rhizoctonia Root Rot ◽  
Green Bridge

Root rot caused by Rhizoctonia spp. is an economically important soilborne disease of spring-planted wheat in growing regions of the Pacific Northwest (PNW). The main method of controlling the disease currently is through tillage, which deters farmers from adopting the benefits of minimal tillage. Genetic resistance to this disease would provide an economic and environmentally sustainable resource for farmers. In this study, a collection of synthetic-derived genotypes was screened in high-inoculum and low-inoculum field environments. Six genotypes were found to have varying levels of resistance and tolerance to Rhizoctonia root rot. One of the lines, SPBC-3104 (‘Vorobey’), exhibited good tolerance in the field and was crossed to susceptible PNW-adapted ‘Louise’ to examine the inheritance of the trait. A population of 190 BC1-derived recombinant inbred lines was assessed in two field green bridge environments and in soils artificially infested with Rhizoctonia solani AG8. Genotyping by sequencing and composite interval mapping identified three quantitative trait loci (QTL) controlling tolerance. Beneficial alleles of all three QTL were contributed by the synthetic-derived genotype SPCB-3104.

QTL mapping for seedling morphology under drought stress in wheat cross synthetic (W7984)/Opata

2018 ◽  
Vol 16 (4) ◽  
pp. 359-366
Author(s):  
Maria Khalid ◽  
Alvina Gul ◽  
Rabia Amir ◽  
Mohsin Ali ◽  
Fakiha Afzal ◽  
...  
Keyword(s):  
Drought Stress ◽  
Recombinant Inbred Lines ◽  
Genotyping By Sequencing ◽  
Interval Mapping ◽  
Wheat Breeding ◽  
Seedling Stage ◽  
Poor Correlation ◽  
Root Weight ◽  
Phenotypic Variance ◽  
Seedling Morphology

AbstractDrought stress ‘particularly at seedling stage’ causes morpho-physiological differences in wheat which are crucial for its survival and adaptability. In the present study, 209 recombinant inbred lines (RILs) from synthetic wheat (W7984)× ‘Opata’ (also known as SynOpRIL) population were investigated under well-watered and water-limited conditions to identify quantitative trait loci (QTL) for morphological traits at seedling stage. Analysis of variance revealed significant differences (P < 0.01) among RILs, and water treatments for all traits with moderate to high broad sense heritability. Pearson's coefficient of correlation revealed positive correlation among all traits except dry root weight that showed poor correlation with fresh shoot weight (FSW) under water-limited conditions. A high-density linkage map was constructed with 2639 genotyping-by-sequencing markers and covering 5047 cM with an average marker density of 2 markers/cM. Composite interval mapping identified 16 QTL distributed over nine chromosomes, of which six were identified under well-watered and 10 in water-limited conditions. These QTL explained from 4 to 59% of the phenotypic variance. Six QTL were identified on chromosome 7B; three for shoot length under water-limited conditions (QSL.nust-7B) at 64, 104 and 221 cM, two for fresh root weight (QFRW.nust-7B) at 124 and 128 cM, and one for root length (QRL.nust-7B) at 122 cM positions. QFSW.nust-7B appeared to be the most significant QTL explaining 59% of the phenotypic variance and also associated with FSW at well-watered conditions. These QTL could serve as target regions for candidate gene discovery and marker-assisted selection in wheat breeding.

scholarly journals Optimum Timing of Preplant Applications of Glyphosate to Manage Rhizoctonia Root Rot in Barley

Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 304-310 ◽  
Author(s):  
E. M. Babiker ◽  
S. H. Hulbert ◽  
K. L. Schroeder ◽  
T. C. Paulitz
Keyword(s):  
Disease Severity ◽  
Pacific Northwest ◽  
Root Rot ◽  
Field Experiments ◽  
Herbicide Application ◽  
Rhizoctonia Root Rot ◽  
The Pacific ◽  
Seminal Roots ◽  
Polymerase Chain ◽  
High Level

Rhizoctonia root rot, caused by Rhizoctonia solani AG-8 and R. oryzae, is considered one of the main deterrents for farmers to adopt reduced-tillage systems in the Pacific Northwest. Because of the wide host range of Rhizoctonia spp., herbicide application before planting to control weeds and volunteer plants is the main management strategy for this disease. To determine the effect of timing of glyphosate applications on the severity of Rhizoctonia root rot of barley, field experiments were conducted in 2007, 2008, and 2009 in a field naturally infested with a high level of both R. solani and R. oryzae. Crop volunteer plants and weeds were allowed to grow over the winter and plots were sprayed with glyphosate at 42, 28, 14, 7, and 2 days prior to planting. As the herbicide application interval increased, there were significant increases in shoot length, length of the first true leaf, and number of healthy seminal roots and a decrease in disease severity. Yield and the number of seminal roots did not show a response to herbicide application interval in most years. The activity of R. solani, as measured by toothpick bioassay and real-time polymerase chain reaction, declined over time in all treatments after planting barley. The herbicide application interval required to meet 80 and 90% of the maximum response (asymptote) for all plant and disease measurements ranged from 11 to 27 days and 13 to 37 days, respectively. These times are the minimum herbicide application intervals required to reduce disease severity in the following crop.

scholarly journals Genotyping by sequencing for identification and mapping of QTLs for bioenergy-related traits in sweet sorghum

2020 ◽  
Author(s):  
Kanokwan Teingtham ◽  
David M. Braun ◽  
Ismail Dweikat
Keyword(s):  
Sweet Sorghum ◽  
Recombinant Inbred Lines ◽  
Genotyping By Sequencing ◽  
Interval Mapping ◽  
Chromosome 1 ◽  
Total Biomass ◽  
Sequencing Analysis ◽  
Nucleotide Polymorphisms ◽  
Sugar Transporter ◽  
Major Qtls

AbstractSweet sorghum (Sorghum bicolor L. Moench) is a promising bioenergy crop. To increase the productivity of this crop, marker-assisted breeding will be important to advance genetic improvement of sweet sorghum. The objective of the present study was to identify quantitative trait loci (QTLs) associated with bioenergy-related traits in sweet sorghum. We used 188 F7 recombinant inbred lines (RILs) derived from a cross between sweet sorghum (Wray) and grain sorghum (Macia). The RILs and their parental lines were grown at two locations in 2012 and 2013. Genotyping-by-sequencing analysis of the RILs allowed the construction of a map with 979 single nucleotide polymorphisms. Using the inclusive composite interval mapping of additive QTLs, major QTLs for flowering time and head moisture content were detected on chromosome 6, and explained 29.45% and 20.65% of the phenotypic variances (PVE), respectively. Major QTLs for plant height (29.51% PVE) and total biomass yield (16.46% PVE) were detected on chromosome 7, and QTLs for stem diameter (9.43% PVE) and 100 seed weight (22.97% PVE) were detected on chromosome 1. A major QTL for brix (39.92% PVE) and grain yield (49.14%) PVE co-localized on chromosome 3, was detected consistently across four environments, and is closely associated with a SWEET sugar transporter gene. Additionally, several other QTLs for brix identified in this study or reported previously were found to be associated with sugar transporter genes. The identified QTLs in this study will help to further understand the underlying genes associated with bioenergy-related traits and could be used for development of molecular markers for marker-assisted selection.

scholarly journals Root Traits Play a Role in Integrated Management of Fusarium Root Rot in Snap Beans

HortScience ◽  
2003 ◽  
Vol 38 (2) ◽  
pp. 187-191 ◽  
Author(s):  
S. Snapp ◽  
W. Kirk ◽  
B. Román-Avilés ◽  
J. Kelly
Keyword(s):  
Root Rot ◽  
Lateral Root ◽  
Management Practices ◽  
Root Length Density ◽  
Integrated Management ◽  
Recombinant Inbred Lines ◽  
Genetic Resistance ◽  
Limiting Factor ◽  
Snap Bean ◽  
Root Vigor

Fusarium root rot is a major limiting factor in snap bean (Phaseolus vulgaris L.) production. The level of genetic resistance in commercial bean cultivars is minimal and disease is frequently exacerbated by environmental factors. We investigated the contribution of vigorous, adventitious roots to enhancing root rot tolerance in snap bean. Seedling root system architecture was evaluated in 17 recombinant inbred lines (RILs) from a cross of a resistant snap bean line (FR266) and a susceptible dry bean cultivar (Montcalm). The RILs varied in tolerance to Fusarium root rot. Although overall length and branching density (as measured by fractal dimension and meristem numbers) of root systems were not related to root rot resistance, the lateral root number at the root: shoot interface was positively correlated with genotype tolerance (R2 = 0.6*). Root diameter was also positively correlated with tolerance; this is consistent with the hypothesis that larger adventitious and basal roots are beneficial under disease stress. A field-based study of commercial snap bean cultivars compared raised and flat-bed systems of production, in a soil inoculated with Fusarium solani f. sp. phaseoli. Substantially greater yields (40% to 90%) were observed in raised beds. Root vigor was relatively high (root length density >0.2 cm·cm−3) and root rot scores were lower with raised than with flat-beds, in 2001, but not in 2000. Overall, this is suggestive that integrated crop management practices can improve lateral root vigor and reduce root rot severity.

scholarly journals Biological Control of Wheat Root Diseases by the CLP-Producing Strain Pseudomonas fluorescens HC1-07

2014 ◽  
Vol 104 (3) ◽  
pp. 248-256 ◽  
Author(s):  
Ming-Ming Yang ◽  
Shan-Shan Wen ◽  
Dmitri V. Mavrodi ◽  
Olga V. Mavrodi ◽  
Diter von Wettstein ◽  
...  
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Root Rot ◽  
Gaeumannomyces Graminis ◽  
Protease Production ◽  
Ionization Mass ◽  
Soilborne Disease ◽  
Rhizoctonia Root Rot ◽  
Take All

Pseudomonas fluorescens HC1-07, previously isolated from the phyllosphere of wheat grown in Hebei province, China, suppresses the soilborne disease of wheat take-all, caused by Gaeumannomyces graminis var. tritici. We report here that strain HC1-07 also suppresses Rhizoctonia root rot of wheat caused by Rhizoctonia solani AG-8. Strain HC1-07 produced a cyclic lipopeptide (CLP) with a molecular weight of 1,126.42 based on analysis by electrospray ionization mass spectrometry. Extracted CLP inhibited the growth of G. graminis var. tritici and R. solani in vitro. To determine the role of this CLP in biological control, plasposon mutagenesis was used to generate two nonproducing mutants, HC1-07viscB and HC1-07prtR2. Analysis of regions flanking plasposon insertions in HC1-07prtR2 and HC1-07viscB revealed that the inactivated genes were similar to prtR and viscB, respectively, of the well-described biocontrol strain P. fluorescens SBW25 that produces the CLP viscosin. Both genes in HC1-07 were required for the production of the viscosin-like CLP. The two mutants were less inhibitory to G. graminis var. tritici and R. solani in vitro and reduced in ability to suppress take-all. HC1-07viscB but not HC-07prtR2 was reduced in ability to suppress Rhizoctonia root rot. In addition to CLP production, prtR also played a role in protease production.

scholarly journals Rapid Quantitative Assessment of Rhizoctonia Resistance in Roots of Selected Wheat and Barley Genotypes

Plant Disease ◽  
2016 ◽  
Vol 100 (3) ◽  
pp. 640-644
Author(s):  
Patricia A. Okubara ◽  
Natalie Leston ◽  
Ute Micknass ◽  
Karl-Heinz Kogel ◽  
Jafargholi Imani
Keyword(s):  
Pacific Northwest ◽  
Management Practices ◽  
Production Systems ◽  
Low Cost ◽  
Genetic Resistance ◽  
Bare Patch ◽  
Rhizoctonia Root Rot ◽  
The Pacific ◽  
Wide Range ◽  
Barley Genotypes

Rhizoctonia solani AG8, causal agent of Rhizoctonia root rot and bare patch in dryland cereal production systems of the Pacific Northwest United States and Australia, reduces yields in a wide range of crops. Disease is not consistently controlled by available management practices, so genetic resistance would be a desirable resource for growers. In this report, we describe three rapid and low-cost assays for R. solani AG8 resistance in wheat and barley, with the view of facilitating screens for genetic resistance in these hosts. The first assay uses 50-ml conical centrifuge tubes containing soil infested with R. solani AG8 on a substrate of ground oats. The second assay uses roots of 3-day-old seedlings directly coated with infested ground oats, followed by incubation in plastic dishes. The third assay, suitable for barley, uses whole infested oat kernels in 50-ml tubes. Symptoms are quantified on the bases of root fresh weight and total root length at 7 and 3 days for the tube and coating assays, respectively. Each of the assays show the same disease differential between susceptible and partially resistant wheat genotypes. The assays can be conducted in the laboratory, growth chamber, or greenhouse.

scholarly journals Development of GUS Reporter Gene System for Aphanomyces Root Rot Screening in Pea

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 615b-615
Author(s):  
Clarice J. Coyne ◽  
Fred J. Muehlbauer
Keyword(s):  
Reporter Gene ◽  
Root Rot ◽  
Recombinant Inbred Lines ◽  
Marker Gene ◽  
Genetic Resistance ◽  
Aphanomyces Euteiches ◽  
Immunosorbant Assay ◽  
Gus Reporter ◽  
Causal Pathogen ◽  
Reporter Gene System

Aphanomyces root rot of pea (Pisum sativum) in many pea-growing regions. The genetic resistance to this fungal pathogen is quantitatively inherited and confers levels of tolerance to the disease. Genetic gains in selection have been hampered by the difficulty of differentiating the highly tolerant from tolerant lines in segregating populations. Reporter gene systems have been useful in studying genetic resistance to other soil-borne pathogens. We have transformed an isolate of Aphanomyces euteiches, the causal pathogen, with a reporter gene β-glucuronidase (GUS) and a selectable marker gene, hygromycin phosphotransferase or neomycin phosphotransferase. The transformed lines constitutively express GUS as determined fluorimetrically by measuring the conversion of 4-methylumbelliferyl glucuronide to 4-methlyumbelliferone. The efficacy of this GUS enzyme assay will be compared with an indirect enzyme linked immunosorbant assay (ELISA) and visual disease development ratings in inoculated seedlings of three populations recombinant inbred lines of pea segregating for tolerance.

Brachypodium distachyon genotypes vary in resistance to Rhizoctonia solani AG8

2016 ◽  
Vol 43 (2) ◽  
pp. 189 ◽  
Author(s):  
Katharina Schneebeli ◽  
Ulrike Mathesius ◽  
Alexander B. Zwart ◽  
Jennifer N. Bragg ◽  
John P. Vogel ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Root Rot ◽  
Quantitative Resistance ◽  
Brachypodium Distachyon ◽  
Genetic Resistance ◽  
Sole Source ◽  
Wheat Root ◽  
Anastomosis Group ◽  
Seedling Vigour ◽  
Rhizoctonia Root Rot

Brachypodium distachyon (L.)P.Beauv. (Bd) has previously been developed as a pathosystem model for the wheat root rot pathogen Rhizoctonia solani Kühn anastomosis group 8 (AG8). Here we explore variation in resistance to R. solani AG8 in Bd, to determine whether genomic tools could be used to find Bd genes involved in the grass defence response, with the aim of using this information for the improvement of Rhizoctonia root rot resistance in wheat. We looked for variation in resistance to R. solani AG8 in a diverse Bd natural accession collection and in Bd T-DNA insertion lines selected based on putative mechanisms reported for tagged genes. All lines were susceptible to the pathogen. Repeatable and significant variation in resistance was measured in both groups, with greater variation in resistance found across the natural accessions than in the T-DNA lines. The widest and most repeatable variation in resistance was between lines Koz-3 and BdTR 13a. The ratio of R. solani AG8-inoculated to uninoculated root length for line Koz-3 was 33% greater than the same ratio for line BdTR 13a. The increased resistance of Koz-3 was associated with nodal root initiation in response to the pathogen. A negative correlation between seedling vigour and resistance was observed, but found not to be the sole source of variation in resistance to R. solani AG8. The only T-DNA line with significantly greater resistance to R. solani AG8 than the reference line had an insertion in a putative galactosyltransferase gene; however, this result needs further confirmation. Genetic resistance to Rhizoctonia root rot is not available in wheat cultivars and only a few instances of quantitative resistance to the pathogen have been described within close relatives of wheat. Brachypodium distachyon offers potential for further investigation to find genes associated with quantitative resistance and mechanisms of tolerance to R. solani AG8.

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