Location: Wheat, Sorghum and Forage ResearchTitle: Amylose-free (“waxy”) wheat colonization by fusarium spp. and response to fusarium head blight
|WEGULO, STEPHEN - University Of Nebraska|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2018
Publication Date: 5/1/2019
Citation: Funnell-Harris, D.L., Graybosch, R.A., O'Neill, P.M., Duray, Z.T., Wegulo, S.N. 2019. Amylose-free (“waxy”) wheat colonization by fusarium spp. and response to fusarium head blight. Plant Disease. 103(5):972-983. https://doi.org/10.1094/PDIS-05-18-0726-RE.
Interpretive Summary: Waxy (amylose-free) wheat grain is more digestible than normal grain and can be used in specialty food products and to increase shelf-life of baked goods. However, the first Great Plains adapted waxy cultivar, Mattern, is vulnerable to Fusarium head blight (FHB) disease which is caused by the fungus Fusarium graminearum. This disease is highly damaging to grain and the fungus produces the toxin called DON, which can make the grain unusable for humans and animals. We developed several new waxy lines and assessed them, along with Mattern, for natural Fusarium infection and DON in years with low FHB (Experiment 1) and for disease symptoms, Fusarium Damaged Kernels (FDK) and DON levels, during an FHB epidemic (Experiment 2), as compared with normal cultivars. For Experiment 1, F. graminearum infections were similar between waxy and normal lines. For Experiment 2, there were no differences in disease symptoms, FDK and DON levels when comparing all waxy lines with all normal lines showing that waxy grain is not inherently more vulnerable to infection during an FHB epidemic. When considering individual lines, Mattern had the highest disease levels of all lines while the new lines, PI 677876 and PI 677877, had disease measurements noticeably less than Mattern and similar to the normal cultivar, Overland. These newly-developed waxy lines show promise for breeding advanced waxy lines that can tolerate FHB infections.
Technical Abstract: Hexaploid waxy wheat (Triticum aestivum L.) has null mutations in Wx genes and grain lacking amylose with increased digestibility and usability for specialty foods. The waxy cultivar Mattern is susceptible to Fusarium head blight (FHB) caused by Fusarium graminearum species complex that produces the mycotoxin deoxynivalenol (DON). In Experiment 1, conducted during low natural FHB, grain from waxy breeding lines, Mattern, and wild-type breeding lines and cultivars, were assessed for Fusarium infection and DON concentration. Nine Fusarium species and species complexes were detected from internally-infected (disinfested) grain; F. graminearum-infections were not different between waxy and wild-type. Surface- and internally-infected grain (non-disinfested), had greater numbers of Fusarium isolates across waxy versus wild-type, but F. graminearum-like infections were similar; however, DON levels were higher in waxy. In Experiment 2, conducted during a timely epidemic, disease severity, Fusarium-damaged kernels (FDK), and DON were assessed for waxy breeding lines, Mattern, and wild-type cultivars. Disease severities and FDK were not significantly different from wild-type but DON was higher in waxy than wild-type lines. Across both experiments, waxy breeding lines, Plant Introductions 677876 and 677877, responded similarly to FHB as moderately-resistant wild-type cultivar Overland, showing promise for breeding advanced waxy cultivars with reduced FHB susceptibility.