Pyramiding QTL increases seedling resistance to crown rot (Fusarium pseudograminearum) of wheat (Triticum aestivum)

AbstractHexaploid spring wheat (Triticum aestivum) may exhibit significant crown rot disease responses to infection by Fusarium pseudograminearum, with a range of susceptibility levels available in commercial cultivars. Dry conditions during grain-fill may lead to the expression of prematurely senescing culms, which typically fail to set grain. Assessment of hexaploid spring wheat plants exhibiting both non-senescent and prematurely senescent culms was performed using visual discolouration, Fusarium pseudograminearum biomass, vascular colonisation and quantification of wheat DNA in culm sections sampled at three different heights above the crown and at the peduncle. A comparison of these parameters at four time points from milk development, when senescent culms are first observed, to maturity was conducted. Samples from six commercial cultivars were collected in 2014 from Narrabri and Tamworth, New South Wales and Wellcamp, Queensland. Prematurely senescent culms exhibited greater visual discolouration, Fusarium pseudograminearum biomass and vascular colonisation than non-senescent culms in each cultivar. Colonisation of xylem and phloem tissue was extensive in the basal portions of prematurely senescent culms (36 to 99%), and suggests significant impacts on water and nutrient movement during crown rot disease. Maturation coincided with significant changes in Fusarium pseudograminearum biomass and vascular colonisation. Wheat DNA content varied among cultivars, culm conditions, culm sections and sampling times. The variation in the severity of disease states between culms of the same plant suggests that the timing of initiation of infection in individual culms may vary.

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Assessment of Infection by Fusarium pseudograminearum in Wheat Seedling Tissues Using Quantitative PCR and a Visual Discoloration Scale

Plant Disease ◽

10.1094/pdis-12-11-1050-re ◽

2012 ◽

Vol 96 (11) ◽

pp. 1661-1669 ◽

Cited By ~ 23

Author(s):

Noel L. Knight ◽

Mark W. Sutherland ◽

Anke Martin ◽

Damian J. Herde

Keyword(s):

Fungal Biomass ◽

Leaf Sheath ◽

Crown Rot ◽

Fungal Colonization ◽

Seedling Resistance ◽

Disease Symptoms ◽

Wheat Genotypes ◽

Fusarium Pseudograminearum ◽

Fungal Dna ◽

Visual Assessments

Assessment among cereal genotypes of relative seedling resistance to the crown rot pathogen Fusarium pseudograminearum has been primarily based on visual discoloration of the leaf sheaths. This study is the first to investigate the relationship between the widely used visual rating of seedling leaf sheath discoloration and the degree of colonization of these tissues by the pathogen, based on quantitative polymerase chain reaction (qPCR) of fungal DNA using primers specific for the translation elongation factor α sequence. Fourteen-day-old seedlings of four hard white spring wheat genotypes which differ in their degree of resistance to the pathogen, based on the expression of visible symptoms, were inoculated using a droplet method and assessed weekly from 7 to 35 days after inoculation (dai) for both discoloration and fungal DNA content per unit of tissue weight. Both visual assessment of disease symptoms and qPCR of fungal biomass indicated significant differences between the partially resistant and susceptible wheat genotypes from 14 dai. Visual discoloration of leaf sheath tissues was strongly correlated with fungal biomass estimated by qPCR in all four genotypes; however, this correlation became weaker with increasing time after inoculation. Significant correlations between these parameters were indicated at 14, 21, and 28 dai whereas, by 35 dai, the correlation was not significant. Evaluation of plants at 14 dai provided a rapid test which gave clear discrimination between lines for both parameters and was the time point of closest correlation between fungal colonization and disease symptoms. Symptom expression at all times following inoculation was accompanied by tissue infection, and at no time was symptomless infection observed under this screening environment. These qPCR results confirm that visual assessments of disease symptoms reflect the extent of tissue colonization by the pathogen in recently colonized tissues and confirm the validity of visual assessments for disease rating in high-throughput screening of breeding materials.

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Disease responses of hexaploid spring wheat (Triticum aestivum) culms exhibiting premature senescence (dead heads) associated with Fusarium pseudograminearum crown rot

European Journal of Plant Pathology ◽

10.1007/s10658-020-02158-8 ◽

2020 ◽

Vol 159 (1) ◽

pp. 191-202

Author(s):

Noel L. Knight ◽

Bethany Macdonald ◽

Cassy Percy ◽

Mark W. Sutherland

Keyword(s):

Triticum Aestivum ◽

Spring Wheat ◽

Crown Rot ◽

Premature Senescence ◽

Fusarium Pseudograminearum

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Investigating the Impact of Root-Lesion Nematodes (Pratylenchus thornei) and Crown Rot (Fusarium pseudograminearum) on Diverse Cereal Cultivars in a Conservation Farming System

Agronomy ◽

10.3390/agronomy11050867 ◽

2021 ◽

Vol 11 (5) ◽

pp. 867

Author(s):

John P. Thompson ◽

Timothy G. Clewett

Keyword(s):

Grain Yield ◽

Soil Profile ◽

Crown Rot ◽

Tolerance Index ◽

Initial Population ◽

Fusarium Pseudograminearum ◽

Conservation Farming ◽

Pratylenchus Thornei ◽

Fourth Experiment ◽

The Impact

In two experiments on a farm practicing conservation agriculture, the grain yield of a range of wheat cultivars was significantly (p < 0.001) negatively related to the post-harvest population densities of Pratylenchus thornei in the soil profile to 45 cm depth. In a third and fourth experiment with different rotations, methyl bromide fumigation significantly (p < 0.05) decreased (a) a low initial population density of P. thornei in the soil profile to 90 cm depth and (b) a high initial population of P. thornei to 45 cm depth, and a medium level of the crown rot fungus, Fusarium pseudograminearum, at 0–15 cm depth to a low level. For a range of wheat and durum cultivars, grain yield and response to fumigation were highly significantly (p < 0.001) related to (a) the P. thornei tolerance index of the cultivars in the third experiment, and (b) to both the P. thornei tolerance index and the crown rot resistance index in the fourth experiment. In the latter, grain yield was significantly (p < 0.001) positively related to biomass at anthesis and negatively related to percentage whiteheads at grain fill growth stage. One barley cultivar was more tolerant to both diseases than the wheat and durum cultivars. Crop rotation, utilizing crop cultivars resistant and tolerant to both P. thornei and F. pseudograminearum, is key to success for conservation farming in this region.

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Colonization of Durum Wheat (Triticum turgidum L. var. durum) Culms Exhibiting Premature Senescence (Dead Heads) Associated with Fusarium pseudograminearum Crown Rot

Plant Disease ◽

10.1094/pdis-03-17-0415-re ◽

2017 ◽

Vol 101 (10) ◽

pp. 1788-1794 ◽

Cited By ~ 4

Author(s):

Noel L. Knight ◽

Bethany Macdonald ◽

Mark W. Sutherland

Keyword(s):

Durum Wheat ◽

Disease Susceptibility ◽

Triticum Turgidum ◽

Crown Rot ◽

Vascular Bundles ◽

Fusarium Crown Rot ◽

Fusarium Pseudograminearum ◽

Field Samples ◽

Key Factor ◽

Significant Disease

Fusarium crown rot is a significant disease of durum wheat (Triticum turgidum L. var. durum), which exhibits high levels of disease susceptibility. The most extreme symptom of crown rot is a prematurely senescing culm that typically fails to set grain. Individual crown rot-affected durum wheat plants displaying both nonsenescent and prematurely senescent culms were harvested to compare visual discoloration, Fusarium pseudograminearum biomass, and vascular colonization in culm sections sampled at three different heights above the crown. Field samples of EGA Bellaroi were collected at Wellcamp, QLD, in 2011, 2012, 2013, and 2014, and of Hyperno at Narrabri, NSW, in 2014. Prematurely senescent culms exhibited greater visual discoloration, F. pseudograminearum biomass, and vascular colonization than nonsenescent culms in each year they were examined. The extent of these differences varied between environments and timing of collection in each year. Vascular colonization initially occurred in xylem vessels and spread into phloem tissues as disease severity increased. The increased presence of hyphae in vascular bundles of prematurely senescing culms provides strong evidence for the hypothesis that restriction of water and nutrient movement in a diseased culm is a key factor in crown rot severity.

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Genetic diversity of Australian Fusarium pseudograminearum populations causing crown rot in wheat

European Journal of Plant Pathology ◽

10.1007/s10658-020-02198-0 ◽

2021 ◽

Author(s):

Mohammed Khudhair ◽

F. Obanor ◽

K. Kazan ◽

D. M. Gardiner ◽

E. Aitken ◽

...

Keyword(s):

Genetic Diversity ◽

Crown Rot ◽

Fusarium Pseudograminearum

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Genetic relationships between resistances to Fusarium head blight and crown rot in bread wheat (Triticum aestivum L.)

Theoretical and Applied Genetics ◽

10.1007/s00122-010-1363-0 ◽

2010 ◽

Vol 121 (5) ◽

pp. 941-950 ◽

Cited By ~ 51

Author(s):

Hao Bing Li ◽

Guo Qiang Xie ◽

Jun Ma ◽

Gui Ru Liu ◽

Shu Min Wen ◽

...

Keyword(s):

Triticum Aestivum ◽

Fusarium Head Blight ◽

Bread Wheat ◽

Genetic Relationships ◽

Triticum Aestivum L ◽

Crown Rot ◽

Head Blight

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Response of durum wheat to different levels of zinc and Fusarium pseudograminearum

Crop and Pasture Science ◽

10.1071/cp13306 ◽

2014 ◽

Vol 65 (1) ◽

pp. 61 ◽

Cited By ~ 2

Author(s):

Mohsin S. Al-Fahdawi ◽

Jason A. Able ◽

Margaret Evans ◽

Amanda J. Able

Keyword(s):

Grain Yield ◽

Durum Wheat ◽

Sufficient Conditions ◽

Crown Rot ◽

Limiting Factors ◽

Shoot Biomass ◽

Zn Deficiency ◽

Zinc Efficiency ◽

Fusarium Pseudograminearum ◽

Zn Concentration

Durum wheat (Triticum turgidum ssp. durum) is susceptible to Fusarium pseudograminearum and sensitive to zinc (Zn) deficiency in Australian soils. However, little is known about the interaction between these two potentially yield-limiting factors, especially for Australian durum varieties. The critical Zn concentration (concentration of Zn in the plant when there is a 10% reduction in yield) and degree of susceptibility to F. pseudograminearum was therefore determined for five Australian durum varieties (Yawa, Hyperno, Tjilkuri, WID802, UAD1153303). Critical Zn concentration averaged 24.6 mg kg–1 for all durum varieties but differed for the individual varieties (mg kg–1: Yawa, 21.7; Hyperno, 22.7; Tjilkuri, 24.1; WID802, 24.8; UAD1153303, 28.7). Zinc efficiency also varied amongst genotypes (39–52%). However, Zn utilisation was similar amongst genotypes under Zn-deficient or Zn-sufficient conditions (0.51–0.59 and 0.017–0.022 g DM μg–1 Zn, respectively). All varieties were susceptible to F. pseudograminearum but the development of symptoms and detrimental effect on shoot biomass and grain yield were significantly greater in Tjilkuri. Even though crown rot symptoms may still be present, the supply of adequate Zn in the soil helped to maintain biomass and grain yield in all durum varieties. However, the extent to which durum varieties were protected from plant growth penalties due to crown rot by Zn treatment was genotype-dependent.

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