Authors: Yuzhou Xu 1, Wei Zhao 1, Lingling Chai 1, 2, Harold N. Trick 3, Amy Bernardo 4, Paul St. Amand 4, Zhongfu Ni 2, Brett Carver 5, and Guihua Bai 1, 4
1. Kansas State University, Department of Agronomy, Manhattan, KS 66506
2. China Agricultural University, Department of Agronomy, Haidian District, Beijing 100083
3. Kansas State University, Department of Plant Pathology, Manhattan, KS 66506
4. USDA-ARS Hard Winter Wheat Genetics Research Unit, Manhattan, KS 66506
5. Oklahoma State University, Department of Plant and Soil Sciences, Stillwater, OK 74078
Corresponding Author: Yuzhou Xu, yuzhouxu@ksu.edu
Presenting Author: Yuzhou Xu
Poster Video:
Abstract
Fusarium head blight (FHB), mainly caused by Fusarium graminearum, is a devastating disease that poses a severe threat to global wheat production by reducing both grain yield and quality. Utilizing host resistance has been the most effective strategy for the disease control. Among hundreds of resistance quantitative trait loci (QTL) identified for FHB resistance to date, only a few showed stable major effects on FHB resistance in wheat and have been repeatedly detected across multiple studies. One of the previously identified major QTL is QFhb.hwwg-2DS on chromosome arm 2DS and overlaps with a QTL for reduced plant height (Rht). This study conducted map-based cloning to pinpoint the candidate gene underlining QFhb.hwwg-2DS and investigated the genetic relationship between FHB resistance and the plant height. The fine mapping population were generated by continuous selfing of the plants heterozygous in the QFhb.hwwg-2DS region and the heterozygous plants were derived from one recombinant inbred line (RIL) of G97252W x G97380A. The fine mapping populations were genotyped by the flanking markers for QFhb.hwwg-2DS, and the selected critical recombinants were phenotyped for FHB resistance. The results delimited the QFhb.hwwg-2DS region to a 1.6 Mb interval between KASP2D25112886 and KASP2D26715133 with 12 high confidence genes in the region based on IWGSC Refseq v2.1. Gene expression analysis identified a candidate gene encoding a ribonuclease H-like domain protein (RNHL-D1) that underlines rht8 for plant height in the candidate interval, displayed significantly higher FHB severity, but lower plant height. These CRISPR-Cas9 edited plants with the sequence mutation in current research demonstrated that enhanced plant height and reduced FHB severity by QFhb.hwwg-2DS are due to the pleiotropic effect of rht8 encoding the RNHL-D1 protein. Consequently, using of Rht8 as a major source for plant height reduction in FHB-prone regions may compromise FHB resistance therefore, alternative sources of Rht-genes should be considered in those regions.
ACKNOWLEDGEMENT AND DISCLAIMER
This material is based upon work supported by the U.S. Department of Agriculture. This is a cooperative project with the U.S. Wheat & Barley Scab Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.