S. L. Fox

Integrated Metabolo-Proteomic Approach to Decipher the Mechanisms by Which Wheat QTL (Fhb1) Contributes to Resistance against Fusarium graminearum

Background Resistance in plants to pathogen attack can be qualitative or quantitative. For the latter, hundreds of quantitative trait loci (QTLs) have been identified, but the mechanisms of resistance are largely unknown. Integrated non-target metabolomics and proteomics, using high resolution hybrid mass spectrometry, were applied to identify the mechanisms of resistance governed by the fusarium head blight resistance locus, Fhb1, in the near isogenic lines derived from wheat genotype Nyubai. Findings The metabolomic and proteomic profiles were compared between the near isogenic lines (NIL) with resistant and susceptible alleles of Fhb1 upon F. graminearum or mock-inoculation. The resistance-related metabolites and proteins identified were mapped to metabolic pathways. Metabolites of the shunt phenylpropanoid pathway such as hydroxycinnamic acid amides, phenolic glucosides and flavonoids were induced only in the resistant NIL, or induced at higher abundances in resistant than in susceptible NIL, following pathogen inoculation. The identities of these metabolites were confirmed, with fragmentation patterns, using the high resolution LC-LTQ-Orbitrap. Concurrently, the enzymes of phenylpropanoid biosynthesis such as cinnamyl alcohol dehydrogenase, caffeoyl-CoA O-methyltransferase, caffeic acid O-methyltransferase, flavonoid O-methyltransferase, agmatine coumaroyltransferase and peroxidase were also up-regulated. Increased cell wall thickening due to deposition of hydroxycinnamic acid amides and flavonoids was confirmed by histo-chemical localization of the metabolites using confocal microscopy. Conclusion The present study demonstrates that the resistance in Fhb1 derived from the wheat genotype Nyubai is mainly associated with cell wall thickening due to deposition of hydroxycinnamic acid amides, phenolic glucosides and flavonoids, but not with the conversion of deoxynivalenol to less toxic deoxynivalenol 3-O-glucoside.

Unity hard red spring wheat

Unity is a hard red spring wheat that meets the end-use quality specifications of the Canada Western Red Spring class. Unity is the first spring wheat cultivar registered in Canada that contains the antibiosis resistance gene Sm1, which produces a product that reduces the palatability of developing seeds to wheat midge larvae (Sitodiplosis mosellana Gehin). Unity is a partial backcross derivative of McKenzie, using Clark as the donor of the Sm1 gene for midge resistance. Unity was found to be adapted to the eastern wheat growing regions of the Canadian prairies as represented in the Central Bread Wheat Cooperative Registration Test in 2004, 2005 and 2006. For registration testing, the performance of Unity was estimated using the varietal blend Unity VB, which consisted of 90% Unity and 10% Waskada. In comparison to the check cultivars (Katepwa, McKenzie, CDC Teal, AC Barrie, and Superb), Unity was the highest yielding cultivar overall; although not significant, Unity was 5% higher yielding than McKenzie. ...

Strategic approach to mitigating weather induced defects of wheat quality

Weather related defects of wheat quality cause about

Developing standardized methods for breeding preharvest sprouting resistant wheat, challenges and successes in Canadian wheat

100 million of crop losses annually in Canada. The degree of down-grading from post-maturity moisture intensity and duration relates directly to seed deterioration and indirectly to biotic infestation. A multi-pronged project was implemented to study genotype response over environment to moisture-induced degrading factors. In post-physiological maturity field weathering studies, loss in the early response factors, test weight and kernel colour, was similar across cultivars, but cultivars with greater initial test weight and better colour retained grade longer. A later response factor, seed sprouting, is being studied under field and controlled environmental conditions in three genetic populations: one each of a white-seeded, a red seeded hexaploid wheat (Triticum aestivum L.) and a durum wheat (T. turgidum L. var. durum) population. Transgressive segregation for resistance to sprouting was found in the durum and the white seeded hexaploid populations; analysis is pending on the third population. The application of DNA mapping to these populations has generated quantitative trait loci (QTL) associated with sprouting resistance. The populations will be tested for cross applicability of markers identified within this project and from elsewhere. Pre-harvest sprout resistant and susceptible lines selected from the white seeded hexaploid population, SC8021V2/AC Karma, are being used to determine gene expression of factors related to grade protection by transcript profiling of early developmental genes using a wheat EST biochip. A field study of the effect of fungal infestation on the induction of susceptibility to pre-harvest sprouting of genotypes varying for resistance to pre-harvest sprouting has been implemented. Kernel blackpoint may also cause down-grading of wheat, and an investigation of environmental determinants of blackpoint across genotypes is underway.

Waskada hard red spring wheat

Preharvest sprouting (PHS) in spring wheat (Triticum aestivum L.) and durum wheat (T. turgidum L. var durum) causes significant economic losses due to a reduction in grain yield, grain functionality and viability of seed for planting. Average annual estimated losses in Canada are about

Genetic analysis of pre-harvest sprouting in a durum wheat cross

100 million. Genetic resistance to PHS reduces these losses. Development of PHS resistant cultivars is complicated by the effects of factors under genetic control, such as spike morphology, seed dormancy, environment, and kernel diseases. Resistance to PHS has been a breeding priority since the late 1960s. Development of RL4137, which is the primary source of PHS resistance in the Canada Western Red Spring market class, has led to cultivar improvements. A white-seeded derivative of RL4137 is the primary source of PHS in the Canada Prairie Spring White and Canada Western Hard White Spring wheat market classes. Procedures to select for PHS resistance vary among breeding programs, market classes and by degree of inbreeding. Methods include artificial sprouting of intact spikes, germination tests, natural weathering in field trials, artificial weathering trials, and indirect assessment of sprouting by measuring Hagberg falling number. Although many genetic loci have been attributed to preharvest sprouting resistance, application of molecular markers is currently limited due to the complex inheritance of the trait. In Canada, cultivars are characterized for their relative level of PHS resistance and the information is made available to producers.

AC Splendor hard red spring wheat

Waskada is a hard red spring wheat that meets the end-use quality specifications of the Canada Western Red Spring wheat class. Waskada was found to be adapted to the wheat growing regions of the Canadian prairies based on data from the Central Bread Wheat Cooperative Registration Test in 2004, 2005 and 2006. In comparison with the check cultivars (Katepwa, McKenzie, CDC Teal, AC Barrie, and Superb), the grain yield of Waskada was similar to that of the best check in Manitoba and in Saskatchewan. Waskada matures 1 d later than AC Barrie and 1 d earlier than Superb. Waskada had similar height and lodging characteristics as Katepwa and McKenzie. The test weight of Waskada was 1.3 kg hL-1 higher than McKenzie, the best check. Waskada demonstrated moderate resistance to leaf rust but very good resistance to stem rust. Resistance to common bunt and loose smut was good, being similar to the more resistant checks Superb and Katepwa, respectively. Resistance to Fusarium head blight was better than the best check i...

Mycorrhizal colonization, P uptake and yield of older and modern wheats under organic management

Pre-harvest sprouting of durum wheat (Triticum turgidum L. var durum) reduces commercial grade, although the actual effects on processing quality are controversial. Little is known about the genetics of the dormancy component of pre-harvest sprouting resistance in durum. We studied the segregation of dormancy in 98 recombinant inbred lines from a cross of a relatively non-dormant line, CI13102, with a moderately dormant line, Kyle. The lines and parents were grown in field tests over three years, 1996, 1997 and 1998. Spikes were collected at approximately 20% moisture and stored at −23 ∘C. Hand-threshed grain of the lines was germinated, and number of seeds germinated was counted each day. A germination resistance index was calculated to characterize dormancy. Dormancy appeared to be complexly inherited in this cross. Lines were observed that were significantly (P < 0.05) more dormant than the parents. The lines transgressive for dormancy expressed in different combinations of the three environments, indicating an environmental interaction. DNA of lines and parents was tested with simple sequence repeat primers and AFLPs that were used in quantitative trait loci (QTL) analysis of dormancy. Significant QTLs for dormancy were found, with the most notable being on chromosome 1A, where other QTLs for pre-harvest sprouting resistance have been reported in common wheat.

Red smudge infection modifies sprouting response in four wheat lines

AC Splendor is a hard red spring wheat that meets the end-use quality and kernel visual distinguishability specifications of the Canada Western Red Spring class. AC Splendor was evaluated in the Central Bread Wheat Cooperative Registration Test in 1993, 1994 and 1995 and was found to be adapted to the wheat-growing regions of the Canadian prairies. In comparison to the check cultivars Neepawa, Katepwa, Columbus, Roblin and AC Majestic, AC Splendor grain yield was similar to Katepwa, Columbus and Roblin; however, AC Splendor exhibited earlier maturity by 2.8, 7.5 and 1.6 d, respectively. AC Splendor is resistant to Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. E. Henn. that causes the disease stem rust and P. triticina Eriks. that causes leaf rust and has intermediate resistance to Tilletia tritici (Bjerk.) R. Wolff and T. laevis Kuhn in Rabenh. that causes common bunt. Resistance to Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein.) Petch] that causes fusarium head blight is poor. E...

Harvest hard red spring wheat

Kirk, A. P., Entz, M. H., Fox, S. L. and Tenuta, M. 2011. Mycorrhizal colonization, P uptake and yield of older and modern wheats under organic management. Can. J. Plant Sci. 91: 663-667. Arbuscular mycorrhizal fungi (AMF) are important for plant nutrient uptake, and mycorrhizal dependence varies between wheat genotypes. Cultivar selection under fertilized conditions may have reduced mycorrhizal associations in modern cultivars. This study investigated AMF colonization, tissue P and grain yield of five modern (post 1990) and five older (pre 1970) spring wheat cultivars over 4 site-years in Manitoba. Older cultivars actually had significantly lower AMF colonization and grain yield than modern cultivars, but no tissue P concentration differences were observed. The two highest yielding lines were released after 2004, and one of these (FBC Dylan) was selected for suitability in organic farming systems.