Alberta Regional Meeting, 2010/Réunion régionale de l'Alberta, 2010
Plant defence and drought tolerance genes interaction in triticale (× Triticosecale ) seedlings during osmotic stress. C. BADEA, M. FRICK, Y. XU, O. ZABENEH, A. COMEAU, R. WESELAKE AND A. LAROCHE. Lethbridge Research Centre, Agriculture and Agri-Food Canada (AAFC), 5403 1st Avenue South, Lethbridge, AB T1J 4B1, Canada; (A.C.) Research Centre, AAFC, 2560 Hochelaga Boulevard, Quebec City, QC G1V 2J3, Canada; and (R.W.) Department of Agriculture, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
Stress is a common factor during a plant's growth and development due to its sessile state. Studies have shown that most plants respond to stress in a similar two-step manner. The initial step is a cellular protection mechanism directing an increase in molecules such as cytoplasmic calcium followed by a graduate increase in reactive oxygen species (ROS). The second step is the appearance of different stimuli or signals to induce a gene regulation response to minimize the impact of the specific stress. Some of the components within these pathways during the first response step amongst different abiotic and biotic stresses are common. Moreover, the existence of a core of plant stress response genes, named PCESR (plant core environmental stress response proteins) has been previously suggested. After transcriptome analysis of triticale (×Triticosecale Wittm.) seedlings under osmotic drought stress using next generation sequencing (NGS) technology, we have identified more than 5000 differentially expressed genes involved not only in drought, as expected, but also many other stresses such as cold, salinity as well as response to pathogens. Our data analyses reveal a collection of genes in the plant response to abiotic and biotic stresses and further confirm results found in similar studies in different plant species.
Effect of downy mildew on growth and yield loss in field pea. K. F. CHANG, S. F. HWANG, S. E. STRELKOV, B. D. GOSSEN, G. D. TURNBULL AND D. J. BING. Field Crop Development Centre, Alberta Agriculture and Rural Development (AARD), 6000 C & E Trail, Lacombe, AB T4L 1W8, Canada; (S.F.H., G.D.T.) Crop Diversification Centre North, AARD, 17 507 Fort Road N.W., Edmonton, AB T5Y 6H3, Canada; (S.E.S.) Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (B.D.G.) Saskatoon Research Centre, Agriculture and Agri-Food Canada (AAFC), 107 Science Place, Saskatoon, SK S7N 0X2, Canada; and (D.J.B.) Lacombe Research Centre, AAFC, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada
Downy mildew, caused by Peronospora viciae f.sp. pisi Boerema & Verh., has caused substantial damage to field pea crops in Alberta, particularly under the cool, wet conditions experienced in 2010. A total of 150 healthy and diseased plants were sampled in a W-pattern from an infested field in central Alberta on 27 July 27 2010. Plant height and pod length and width were recorded to evaluate the impact of downy mildew on vegetative and reproductive development in pea plants. Plant growth and pod size were reduced in the diseased plants. Just prior to harvest in 2010, over 300 plants in four infested commercial fields of pea were sampled in a W-Pattern. Disease severity, pod numbers and yield per plant were recorded to assess the impact of downy mildew on yield. Pod numbers decreased and yield losses increased with increasing disease severity. These results indicate that moderately severe downy mildew can reduce pod size, number of pods and yield by 50–75%.
Efficacy of boron formulations against primary infection of Plasmodiophora brassicae in Shanghai pak choy. A. DEORA, B. D. GOSSEN AND M. R. MCDONALD. Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada; and (M.R.M.) Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
Plasmodiophora brassicae Woronin, a soilborne protist, causes clubroot disease of many crops in the Brassicaceae. Application of boron (B) suppresses the development of clubroot in root hairs. The present study was conducted to assess the impact of commercial formulations and concentrations of B under controlled conditions. Three products were assessed: Boron (H3BO3; 10% B, liquid; Alpine Plant Foods Corporation), BoronMax (boron complexed with plant carbohydrates, 8.1% B, liquid; NutriAg) and Solubor (Na2B8O134H20; 20.5%, powder; U.S. Borax Inc.) as a drench to sand growth medium immediately after planting seeds of Shanghai pak choy cv. Mei Qing Choi (Brassica rapa subsp. Chinensis (Rupr.) var. communis Tsen and Lee). The products were applied at concentrations equivalent to 0, 0.25, 0.5, 1, 2, 4, 8, 16 and 32 kg ha−1. The experiment was designed as a factorial randomized complete block design with four replicates and three plants per experimental unit. Phytotoxicity was observed for each formulation at rates > 2 kg ha−1; germination was inhibited by about 10, 20, 40 and 60% at 4, 8, 16 and 32 kg ha−1, respectively. Solubor was the most effective formulation and the most effective non-phytotoxic rate for all of the formulations was 2 kg. At 2 kg, Solubor reduced primary infection relative to the non-treated control (from 59% of root hairs to 45%), and inhibited development of the pathogen, reducing the proportion of infected root hairs with zoosporangia from 45% to 16% and dehisced zoosporangia from 24% to 5%. Further studies on timing of application are underway.
Production of non-specific esterase by conidia of Peronospora viciae f.sp. pisi . J. FENG, K. F. CHANG, S. F. HWANG, S. E. STRELKOV, B. D. GOSSEN, R. L. CONNER AND D. L. MCLAREN. Crop Diversification Centre North, Alberta Agriculture and Rural Development (AARD), 17 507 Fort Road N.W., Edmonton, AB T5Y 6H3, Canada; (K.F.C.) Crop Development Centre, AARD, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada; (S.E.S.) Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (B.D.G.) Saskatoon Research Centre, Agriculture and Agri-Food Canada (AAFC), 107 Science Place, Saskatoon, SK S7N 0X2, Canada; (R.L.C.) Morden Research Station, AAFC, Unit 100 101 Route 100, Morden, MB R6M 1Y5, Canada; and (D.L.M.) Brandon Research Centre, AAFC, P.O. Box 1000 A, RR3, Brandon, MB R7A 5Y3, Canada
Esterase activity secreted by conidia of pea downy mildew fungus, Peronospora viciae f.sp. pisi Boerema & Verh. was assayed using indoxyl acetate hydrolysis, which generates indigo blue crystals. When conidia were incubated on artificial media in the presence of indoxyl acetate, blue crystals were observed around the conidia. In contrast, no such crystals were produced on the conidia after surface washing by washing buffer, indicating that the esterase activity was extracellular or weakly bound to the conidia surface. Activity of these esterases was inhibited by diisopropyl fluorophosphate, which is selective for serine esterases. Theses observations indicate that P. viciae f.sp. pisi can produce extracellular serine esterases during conidia germination. The importance of these serine esterases for the fungal pathogenicity is under investigation.
The potential of oxidized forms of silver as durable, effective, broad-spectrum foliar fungicides. M. W. HARDING, M. J. UNRUH, C. C. FIFE, R. J. HOWARD, D. A. SOWA AND M. E. OLSON. Innovotech Inc., Suite 101 – 2011 94 Street, Edmonton, AB T6N 1H1, Canada; and (R.J.H.) Crop Diversification Centre South, Alberta Agriculture and Rural Development, 301 Horticultural Station Road East, Brooks, AB T1R 1E6, Canada
Oxidized forms of silver, such as oxysilver nitrate and sodium diperiodatoargentate (III), are toxic to microorganisms at low concentrations (< 50 ppm). We investigated their potential as foliar-applied fungicides against fungal diseases on field-grown pulse crops, e.g. ascochyta blight [Aschochyta rabiei (Pass.) Labr.] on chickpea, mycosphaerella blight [Mycosphaerella pinodes (Berk. & A. Bloxam) Vestergr.] on pea, and white mould [Sclerotinia sclerotiorum (Lib.) de Bary] on dry bean. Small plots (c. 750 m2) of each crop were established in randomized complete block designs and treated with aqueous preparations of oxidized silver products, industry standard fungicides, and water as an untreated check. Oxidized silvers were capable of significantly reducing disease symptoms when applied as foliar sprays and in many cases were equivalent to industry standard fungicides.
Adaptation of Puccinia striiformis f.sp. tritici and f.sp. hordei to different temperatures. M. D. HOLTZ, K. KUMAR AND K. XI. Field Crop Development Centre, Alberta Agriculture and Rural Development, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada
Stripe rust caused by Puccinia striiformis Westend. is a threat to wheat and barley production in Alberta. Strains of P. striiformis f.sp. tritici Eriks. (Pst) that are better adapted to warmer temperatures have been reported spreading throughout the USA. The ability of P. striiformis f.sp. tritici and Puccinia striiformis f.sp hordei Eriks. (Psh) infections to progress at both low (15 °C) and high (23 °C) temperatures was determined in vivo, after an initial 24 h 12 °C incubation period. After 18 days both formae speciales showed significantly reduced latent periods at 23 °C, but only in Pst did this not cause significantly reduced stripe rust severity and sporulation 18 days after inoculation. Infection success was decreased dramatically for both formae speciales at higher temperatures without the initial 24 h 12 °C incubation. Preliminary laboratory tests showed a consistent inhibition of the germination of Psh's urediniospores on water agar at higher temperatures that did not occur with Pst's. The results suggest that Pst is better adapted than Psh to warmer Albertan summers, but cool conditions are still necessary for the initiation of disease development by both formae speciales.
Ratio of resistant to susceptible canola plants affects resting spore populations of Plasmodiophora brassicae . S. F. HWANG, H. U. AHMED, Q. ZHOU, S. E. STRELKOV, B. D. GOSSEN, G. PENG AND G. D. TURNBULL. Crop Diversification Centre North, Alberta Agriculture and Rural Development, 17 507 Fort Road N.W., Edmonton, AB T5Y 6H3, Canada; (S.E.S.) Department of Agriculture and Forestry, University of Alberta, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; and (B.D.G., G.P.) Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada
Clubroot, caused by Plasmodiophora brassicae Woronin, is a growing threat to canola (Brassica napus L.) production in Canada. Clubroot-resistant canola cultivars have recently become available for commercial production in Alberta, but susceptible volunteer canola plants will continue to be present in infested fields for many years. An initial greenhouse study was conducted to assess root size, clubroot severity and resting spore production in a resistant and a susceptible canola cultivar. The two cultivars were planted separately in tubs of infested soilless mix. Root mass was much greater for the susceptible cultivar and was correlated to index of disease (ID) values calculated from clubroot severity (0–3 scale). In a second study, the same cultivars were sown together to produce a range of proportions of resistant to susceptible plants (1:0, 3:1, 1:1, 1:3 and 0:1). At six weeks after sowing, the roots were collected, rated for clubroot severity, then macerated and re-incorporated into the soil. The susceptible cultivar was grown in the re-inoculated soil and assessed after six weeks. Root fresh weight increased and plant height decreased with increasing ID in the initial treatment (ratios of R:S plants). As expected, spore numbers were highest in soil planted with 100% susceptible plants and declined as the proportion of susceptible plants declined. We noted that 11% of the resistant canola plants developed clubroot symptoms. This may indicate that repeated cultivation of this cultivar will result in selection for pathogen phenotypes that can overcome this source of resistance.
Influence of temperature and pH on clubroot [ Plasmodiophora brassicae ] symptom development in canola under controlled environment conditions. H. KASINATHAN, B. D. GOSSEN AND M. R. MCDONALD. Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; and (B.D.G.) Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada
Clubroot is caused by the soilborne biotrophic protist Plasmodiophora brassicae Woronin. The interaction of temperature (10, 15, 20, 25 and 30 °C) and pH (6.0, 6.5, 7.0, 7.5 and 8.0) on the development of clubroot symptoms in canola roots were studied in a trial under controlled environmental conditions arranged in a factorial randomized complete block design with three replicates. Individual seedlings were transplanted into tall plastic pots (10 pots per experimental unit) containing autoclaved, non-calcareous sand and watered with pH-adjusted water using 5% acetic acid or 10% sodium hydroxide to attain desired pH. Each seedling was inoculated with 5 mL of a resting spore solution containing 1 × 106 spores mL−1. Plants were destructively harvested 50 days after inoculation. Clubroot severity was assessed using a 0–3 scale, and a disease severity index (DSI, range 0–100%) was calculated. Clubroot severity was low (< 20% DSI) at 10 °C and 15 °C, regardless of pH. The optimum temperatures for clubroot development were 20 to 25 °C. The highest DSI (99%) was obtained at pH 6 and 25 °C. DSI values were reduced at pH 8, but still high (42%) at 25 °C. The canola plants did not grow well at 30 °C and there are no data from this temperature. The data indicate that clubroot on canola is suppressed at high pH, but severe clubroot can still develop when other conditions are optimum.
Overwintering Puccinia striiformis in central Alberta. K. KUMAR, K. XI, M. HOLTZ, K. TURKINGTON AND D. SALMON. Field Crop Development Centre (FCDC), Alberta Agriculture and Rural Development (AARD), 6000 C & E Trial, Lacombe, AB T4L 1W1, Canada; (K.T.) Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C & E Trial, Lacombe, AB T4L 1W1, Canada; and (D.S.) FCDC, AARD, 5030-50 Street, Lacombe, AB T4L 1W8, Canada
Viable inoculum of Puccinia striiformis Westend was demonstrated for the first time to overwinter on winter wheat in central Alberta. Stripe rust pustules were observed in winter wheat field plots at Lacombe until the middle of March and urediniospores sampled were able to germinate in the laboratory. The polymerase chain reaction (PCR) method detected infection in leaf samples collected from January to May in 2010 from plants artificially inoculated the previous year. Snow cover appeared to be critical for inoculum to overwinter under central Alberta conditions. In separate experiments, significantly higher stripe rust severity was observed in spring wheat and barley seeded adjacent to winter wheat fields than spring seeded wheat fields in all four growing seasons during 2007–2010. When sampled in June and July 2009, more frequent latent infections were detected in wheat and barley seeded in close proximity to winter wheat than those seeded close to spring wheat using PCR. The present study demonstrates that overwintering inoculum on living hosts, known as a green bridge, may play a role in the earlier onset of stripe rust. Spring wheat and barley seeded adjacent to winter wheat fields may result in more severe stripe rust at the end of the season vs. spring crops seeded near spring wheat fields.
Relationship between blackleg symptoms and pathogen load in seed of susceptible and resistant canola cultivars. R. M. LANGE, W. D. DMYTRIW, D. MORTON AND K. D. KENWARD. Alberta Innovates – Technology Futures, P. O. Bag 4000, Vegreville, AB T9C 1T4, Canada; and (D.M., K.D.K.) 20/20 Seed Labs Inc. # 201, 509 – 11 Avenue, Nisku, AB T9E 7N5, Canada
Leptosphaeria maculans (Desmaz.) Ces. & De Not., the causal agent of blackleg disease of canola, was detected by quantitative PCR (qPCR) in seed of Brassica napus L. plants grown in an artificially inoculated field nursery. A four-replicate field trial consisting of 21 spring B. napus canola cultivars was established in Vegreville, Alberta. Plots were inoculated by spraying a mixture of conidia from L. maculans isolates collected in east-central Alberta. The severity of disease symptoms was evaluated using a standard six point scale. Subsequently, seed from each cultivar was collected for DNA isolation and qPCR analysis. DNA was extracted directly from seed. Primers were developed to specifically differentiate L. maculans from Leptosphaeria biglobosa Shoemaker & Brun and other common fungal pathogens of B. napus. These primers were able to detect L. maculans at titres three orders of magnitude below those seen in qPCR assays using previously published primers. The qPCR estimates of L. maculans load in seed were positively associated with symptom severity of the source plants. Symptom severity and the quantity of pathogen DNA were lower in seed of resistant cultivars compared to susceptible cultivars, although L. maculans was detected in seed of all cultivars. Some cultivars previously rated as resistant to blackleg developed severe symptoms.
Evaluation of Brassica germplasm for resistance to clubroot of canola. G. PENG, K. C. FALK, B. JAMES AND R. K. GUGEL. Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada
Clubroot, caused by the protist pathogen Plasmodiophora brassicae Woronin, is a serious disease of brassica crops worldwide and is becoming a serious threat to canola production on the Canadian prairies. The disease was first observed on canola (B. napus L.) in the Edmonton area in 2003, but has since been found in more than 450 fields in Alberta. Contaminated fields have also been reported in Saskatchewan and Manitoba. Since 2009, clubroot resistant canola cultivars have been available to producers, but the durability of these cultivars is unknown. Clubroot resistance genes are generally race specific and therefore it is important to establish a broad base of genetic resistance for the development of new cultivars over the long term. In the current study, over 1000 accessions of Brassica spp. were evaluated against the predominant P. brassicae race (pathotype 3) using a new bioassay system. Twenty accessions, including B. rapa L., B. carinata L., B. nigra (L.) Koch., B. napus, B. juncea (L.) Czern. and B. oleracea L. showed substantial resistance, reducing clubroot severity by 70–100% relative to susceptible controls. These resistance materials are being further characterized.
New races of sunflower downy mildew. K. Y. RASHID. Morden Research Station, Agriculture and Agri-Food Canada, Unit 100 101 Route 100, Morden, MB R6M 1Y5, Canada
Downy mildew, caused by the fungus Plasmopara halstedii (Farl.) Berl. and de Toni, is a widespread disease globally affecting sunflower (Helianthus annuus L.). It is soil- and seed-borne and can survive for several years in the soil. Favourable conditions for epidemics include abundant soil moisture and temperature of ∼17 °C at the seedling stage. The presence of this disease in Manitoba varies annually (20–80% of crops) with trace to 30% infected plants. Yield loss is directly proportional to the per cent infected plants. The virulence of isolates collected from Manitoba during 2005–2010 was assessed on nine differential sunflower genotypes under controlled conditions. Race 700, 710, 720, 730 and 770, and races 300, 320 and 330 are predominant. Races in the 700 group are more virulent on sunflower and are present at higher frequency than the races in the 300 group. Races 100, 200, 400, 500 and 600 are present at low frequency. Most commercial sunflower hybrids express various levels of resistance to races 100 and 500, but are susceptible to race-groups 300 and 700. In addition to the appearance of the new races of downy mildew in Manitoba, 50–80% of the isolates from different years have shown resistance to the metalaxyl (Apron) seed treatment.
NMR structure determination offers insights into the mechanism for toxicity of trichothecenes T-2 and deoxynivalenol. R. A. SHANK, N. A. FOROUD, P. CHAUDHARY, J. T. GOETTEL, T. MONTINA, P. HAZENDONK AND F. EUDES. Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403 1st Avenue South, Lethbridge, AB T1J 4B1, Canada; and (R.A.S., P.C., J.T.G., T.M., P.H.) University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
Fungal toxins, such as those produced by the Fusarium genus, have widespread effects on cereal crops. Among the most toxic are the trichothecenes, including T-2 toxin and deoxynivalenol (DON). These toxins stall protein synthesis through an interaction with the PTC of the ribosome. The current proposed mechanism suggests a nucleophilic attack involving the epoxide ring; however, little is known about the internal dynamics of these molecules, and DFT calculations suggest that the epoxide is partially obscured. Solution and Solid State NMR refinements of the structure were able to determine the rigidity of the ring system, as well as the hydrogen bonding interactions present in these toxins. These preliminary studies provide new insight into the mechanism for toxicity within plant cells, and the interaction of these toxins with the ribosome.
Comparison of the fungicide sensitivity of Alberta and Prince Edward Island isolates of Fusarium graminearum producing either 3- or 15-acetyl deoxynivalenol. T. K. TURKINGTON, R. CLEAR, J. GILBERT, T. NOWICKI, K. O'DONNELL, A. TEKAUZ, T. WARD, A. P. ROONEY, H. KLEIN-GEBBINCK AND R. A. MARTIN. Lacombe/Beaverlodge Research Centre, Agriculture and Agri-Food Canada (AAFC), 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada; (J.G., A.T.) Cereal Research Centre, AAFC, 195 Dafoe Road, Winnipeg, MB R3T 2M9, Canada; (R.C., T.N.) Grain Research Laboratory, Canadian Grain Commission, 1404-303 Main Street, Winnipeg, MB R3C 3G8, Canada; (K.O., T.W., A.P.R.) USA Department of Agriculture, Peoria, IL, USA; and (R.A.M.) Charlottetown Research Centre, AAFC, 440 University Avenue, Charlottetown PE C1A 4N6, Canada
Fusarium graminearum Schwabe of the ‘3ADON’ chemotype is now displacing ‘15ADON’ isolates in Canada, and this shift in chemotype may be related to potential differences in fungicide sensitivity. Fungicide sensitivity was assessed for a total of 12 isolates of F. graminearum; three ‘3ADON’ and three ‘15ADON’ from each of Alberta and Prince Edward Island, Canada. Spezieller Nährstoffarmer (SN) agar plates or 96-well microplates with liquid SN media were amended with 0, 0.78, 2.16, 4.16, 9.00, 16.78 and 30.62 μg mL−1 of commercial tebuconazole (Folicur®). Agar plates were inoculated with mycelial plugs and colony diameters were measured after 72 h at 20 °C. Microplates were inoculated with homogenized mycelial plugs and absorbance at 405 nm was recorded for individual wells on each microplate using a Biotek microplate reader at time 0 and after 72 h of incubation at 20 °C. Results for both the agar plates and microplates were expressed as a percentage of the diameter or absorbance of the unamended control. For both experiments there were consistent significant effects due to fungicide rate for all runs. No significant differences were found due to chemotype in two of three runs of the agar plate experiment and in both runs of the microplate experiment. These results suggest that the ‘3ADON’ and ‘15ADON’ isolates tested had similar sensitivity to tebuconazole.
Oxysilver nitrate is a broadly effective seed treatment for control of seedborne phytopathogenic fungi. M. J. UNRUH, C. C. FIFE, R. J. HOWARD AND M. W. HARDING. Innovotech Inc., Suite 101 – 2011 94 Street, Edmonton, AB T6N 1H1, Canada; and (R.J.H.) Alberta Agriculture and Rural Development, Crop Diversification Centre South, 301 Horticultural Station Road East, Brooks, AB T1R 1E6, Canada
Oxysilver nitrate (Agress®) had previously been demonstrated to be an effective seed treatment for controlling seed-borne bacterial diseases on pulse crops. We investigated the efficacy of Agress® against seed-borne fungal pathogens of potato and chickpea. Potato seed tubers were artificially inoculated with Fusarium sambucinum Fuckel (teleomorph Giberella pulicaris (Fr.) Sacc.) the causal agent of seed piece decay. Additionally, chickpea seed naturally infested with Aschochyta rabiei (Pass.) Labr., the cause of ascochyta blight, was obtained. The inoculated/infested seed was treated with oxysilver nitrate or an industry standard fungicidal seed treatment and compared with a non-treated check. The treated seed was sown in replicated, small-plot field experiments utilizing a randomized complete block design. For potatoes, the efficacy of the seed treatment versus seed piece decay was estimated by plant emergence. Efficacy on chickpea seed was estimated via foliar disease ratings for ascochyta blight. Results of the field trials demonstrated that Agress® was an effective seed treatment for control of seed-borne fungal diseases of potato and chickpea.
Transcript profiling of genes upregulated in the Ruh1 incompatible interaction in Hannchen barley inoculated with Ustilago hordei , the covered smut pathogen. Y. WANG, D. A. GAUDET, C. PENNIKET, M. FRICK, Z. -X. LU, G. BAKKEREN AND A. LAROCHE. Lethbridge Research Centre, Agriculture and Agri-Food Canada (AAFC), 5403 1st Avenue South, Lethbridge, AB T1J 4B1, Canada; and (G.B.) Pacific Agri-Food Research Centre, AAFC, P.O. Box 5000, 4200 Highway 97, Summerland, BC V0H 1Z0, Canada
Barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), and seed-borne barley smut pathogen (Ustilago hordei (Pers.) Lagerh.) provide a model system for comparing molecular mechanisms involved in the host-compatible, -incompatible, and non-host interactions. We used the Affymetrix GeneChip® Wheat Genome Array to compare transcriptional changes occurring in the coleoptiles of two barley cultivars in a compatible interaction with U. hordei, an incompatible reaction conferred by the resistance gene Ruh1, and in the non-host wheat cultivar. The altered transcript profiles of plants suggested that multiple pathways are reprogrammed in response to U. hordei inoculation. For non-host interactions, the jasmonic acid (JA) pathway was preferentially early-upregulated after 48 h, whereas for host-compatible and Ruh1 interactions, both salicylic acid (SA) and JA pathways were upregulated but expression levels were late upregulated in resistant barley at 72 h to 144 h. qRT-PCR profiling revealed specific early upregulation of some PR-, signal transduction related- and plant defence-genes in resistant barley at 29 h to 48 h. Application of methyl jasmonate (MeJA), SA and ethylene to leaves revealed that only PR1.1 was strongly upregulated by all three compounds in both barley and wheat, and the majority of the defence-related genes are only slightly upregulated by these signalling compounds. SA and JA may be the key signalling molecules that activate defence responses against U. hordei in barley.
Stripe rust reactions of barley lines screened in international nurseries. K. XI, K. KUMAR, M. HOLTZ, K. TURKINGTON, J. NYACHIRO, P. JUSKIW AND J. HELM. Field Crop Development Centre, Alberta Agriculture and Rural Development, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada; and (K.T.) Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada
Barley stripe rust caused by Puccinia striiformis Westend. f.sp. hordei Erics. has frequently occurred in the breeding nurseries located in central Alberta and commercial fields in southern Alberta. To breed for resistance, a large amount of barley breeding and germplasm lines have been screened in the stripe rust nurseries in North and South America since 2007. Disease assessments in the nurseries were usually made twice each season by rating infection type and percentage area of diseased leaves and spikes. This screening generated a large amount of data from 2007 to 2009 that required analysis and subsequent interpretation. Principal component analysis was used to select data with satisfactory disease levels and those with similar rating scales were used for assessment timings. This was followed by canonical discriminant analysis to separate stripe rust reactions among barley classes screened in the nurseries. Analyses showed that the two-row barley was generally more resistant than the six-row class. Germplasm lines originally thought to have resistance were consistently more resistant than advanced breeding lines. The majority of Canadian barley cultivars screened were susceptible. A few of the tested cultivars were resistant. The significance of the screening results is discussed in relation to the selection of barley for resistance breeding.
Molecular markers identified that are linked to resistance or susceptibility of barley to scald. S. XUE, J. L. ZANTINGE, K. J. STEENBERGEN AND P. E. JUSKIW. Field Crop Development Centre, Alberta Agriculture and Rural Development, 5030-50 Street, Lacombe, AB T4L 18W, Canada
Barley scald, caused by Rhynchosporium secalis (Oudem.) Davis, is prevalent in central Alberta and causes significant yield and quality losses in barley production. The barley breeding programme at Lacombe has been trying to incorporate durable scald resistance into lines with good malting quality. Cultivar ‘Seebe’ is known to have durable resistance to scald and based on previous molecular marker studies the resistance appeared to be controlled by multiple genes. In order to develop scald resistance using marker-assisted selection, we genotyped 100 F6recombinant inbred lines from the two-row malt barley breeding population J04075 (H93016013/Seebe) with 34 SSR or STS markers. The phenotyping of the lines for scald resistance was assessed in the field in 2009 at Lacombe. The QTL analysis of the marker data identified seven markers linked to the scald disease reactions and each marker accountedfor 4.57–8% of the variation for scald severity. Of the five markers that were used in 2010 to genotype other barley breeding populations with cv ‘Seebe’ parentage background, Ebmac635 (450 bp) was associated with susceptibility, while Bmag0189 (185 bp), Gms27b (131 bp), Gbm1456 (275 bp), and Bmag0187 (187 bp) were linked to resistance. Currently, we are conducting genetic mapping and validation studies for these markers.