Quantitative trait loci for rolled leaf trait in a wheat EMS mutant from Jagger

Authors: RUOLIN, BIAN - Kansas State University; LIU, NA - Kansas State University; XU, YUZHOU - Kansas State University; SU, ZHENQI - Kansas State University; CAI, LINGLING - Kansas State University; Bernardo, Amy; St Amand, Paul; FRITZ, ALLAN - Kansas State University; ZHANG, GUORONG - Kansas State University; RUPP, JESSICA - Kansas State University; AKHUNOV, EDUARD - Kansas State University; Jordan, Katherine; Bai, Guihua

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2022
Publication Date: 3/13/2023
Citation: Ruolin, B., Liu, N., Xu, Y., Su, Z., Cai, L., Bernardo, A.E., St Amand, P.C., Fritz, A., Zhang, G., Rupp, J., Akhunov, E., Jordan, K., Bai, G. 2023. Quantitative trait loci for rolled leaf trait in a wheat EMS mutant from Jagger. Journal of Theoretical and Applied Genetics. https://doi.org/10.1007/s00122-023-04284-3.
DOI: https://doi.org/10.1007/s00122-023-04284-3

Interpretive Summary: Drought stress commonly reduces yield and quality in rain-fed crop production systems worldwide. Leaf rolling is a morphological trait that may protect plants under drought-stressed conditions. We developed a recombinant inbred mapping population from the cross between cultivar ‘Jagger’ and ‘JagMut1095’ (a rolled leaf-susceptible mutant of Jagger) and tested it in five environments. We performed QTL analysis and identified five genes controlling the rolled leaf trait on different chromosomes. The genes on chromosome arm 1AS and chromosome arm 5AL were stable across all field experiments and together explained up to 60% of the variation in leaf rolling. Using the annotated genomic sequence of wheat, we identified several candidate proteins that may underlie each of the genes. Five of the candidates were previously reported to affect leaf rolling in rice, suggesting common mechanisms across species. Gaining a deeper understanding of the rolled leaf trait may help design crop varieties with greater resilience to drought stress.

Technical Abstract: Rolled leaf (RL) is a morphological strategy to protect plants from dehydration under stressed field conditions. Identification of quantitative trait loci (QTLs) underlying RL is essential to breed drought-tolerant wheat cultivars. A mapping population of 154 recombinant inbred lines was developed from the cross between Jagger and JagMut1095 (a mutant of Jagger) to identify QTLs for the RL trait. A linkage map of 3,470 cM was constructed with 1,003 unique SNPs from 21 wheat chromosomes. A total of 10 QTLs were identified for RL on chromosomes 1A, 1B, 2A, 3B, 4A, 4B, 5A, 5B, 6A and 7B, and two of them on chromosomes 1A (QRl.hwwg-1AS) and 5A (QRl.hwwg-5AL) were stable and significant in all field experiments. QRl.hwwg-1AS was located between S1A-5285506 and Exon1A-25 and explained 22.29% to 54.95% of the phenotypic variation. QRl.hwwg-5AL was flanked by the markers S5A-467054214 and S5A-481252100 and explained up to 20.53% of the phenotypic variation. The combined percent phenotypic variation for both QRl.hwwg-1AS and QRl.hwwg-5AL was up to 60.28%. Functional annotation of the high confidence genes in QRl.hwwg-1AS and QRl.hwwg-5AL revealed 53 putative candidate genes encoding proteins for stress response and cell morphology. Among these genes, the rice orthologs of TraesCS1A03G0023500 and TraesCS1A03G0027900 in the QRl.hwwg-1AS interval and TraesCS5A03G0631600, TraesCS5A03G0631700 and TraesCS5A03G0657300 in the QRl.hwwg-5AL interval have been cloned previously and demonstrated to regulate RL through modulating cell morphology in rice. These genes are the putative candidates for 1A and 5A RL QTLs identified in this study.