Physiological and QTL analysis of slow canopy wilting trait for improvement of drought tolerance in soybean

Authors: YE, HENG - University Of Missouri; SONG, LI - University Of Missouri; SCHAPAUGH, WILLIAM - Kansas State University; ALI, LIAKAT - University Of Missouri; RIAR, MANDEEP - North Carolina State University; RAYMOND, RAYMOND - University Of Missouri; LI, YANG - University Of Missouri; VUONG, TRI - University Of Missouri; VALLIYODAN, BABU - University Of Missouri; NETO, ANTONIO - University Of Missouri; KLEPADLO, MARIOLA - University Of Missouri; Song, Qijian; SHANNON, GROVER - University Of Missouri; PENGYIN, CHEN - University Of Missouri; NGUYEN, HENRY - University Of Missouri

Submitted to: G3, Genes/Genomes/Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2019
Publication Date: 4/13/2019
Citation: Ye, H., Song, L., Schapaugh, W.T., Ali, L., Riar, M.K., Raymond, R.N., Li, Y., Vuong, T., Valliyodan, B., Neto, A.P., Klepadlo, M., Song, Q., Shannon, G.J., Pengyin, C., Nguyen, H.T. 2019. Physiological and QTL analysis of slow canopy wilting trait for improvement of drought tolerance in soybean. G3, Genes/Genomes/Genetics. https://doi.org/10.1093/jxb/erz150.
DOI: https://doi.org/10.1093/jxb/erz150

Interpretive Summary: Drought stress can cause a 40% reduction in soybean seed yield. Soybean plants show signs of drought stress as their canopies wilt, but some soybean varieties differ in the time of onset and the severity of canopy wilting in response to drought. Soybean varieties with the slow canopy wilting (SW) phenotype delay canopy/leaf wilting, and have improved yield under drought. Previous studies showed that two exotic soybeans, PI 567690 and PI 567731, exhibited better SW phenotypes, but the genetic mechanisms underlying the SW trait were unclear. Researchers at University of Missouri, North Carolina, Kansas State University and USDA-ARS, Beltsville, MD, deciphered the physiological and genetic mechanisms responsible for improving yield under limited water availability in these two soybeans and validated major genetic factors protecting soybean yield under drought in the field. Their research results in a better understanding of the water-conservation SW mechanism and provides genetic resources for improving drought tolerance in soybeans through various approaches such as gene cloning, editing or gene transferring by natural breeding. Scientists in the government, at universities, and private industry will be able to use these data to improve drought tolerance in soybeans.

Technical Abstract: Slow canopy wilting (SW) has been observed in late maturity-group (MG) soybean [Glycine max (L.) Merr.] genotypes as a favorable phenotypic response to drought. Previous research identified SW as a water-conservation trait controlled by quantitative trait loci (QTL). More recently, two exotic plant-introductions (PI 567690 and PI 567731) were identified as new SW lines at early-MGs. In this research, these two PIs were identified to share the same water-conservation mechanism of limited-maximum transpiration rates as PI 416937. However, different from PI 416937, the transpiration of these PIs were found to be sensitive to an aquaporin inhibitor, suggesting the presence of silver-sensitive aquaporins. Yield test of the selected recombinant-inbred lines from two elite/exotic crosses provided direct evidence to support the benefit of SW for drought tolerance. Four SW QTL were mapped in a Pana × PI 567690 cross at multiple environments to be co-located with previously reported ones. From another cross of Magellan × PI 567731, two new SW QTL were mapped on chromosome 6 and 10, named as qSW_Gm06 and qSW_Gm10. These two QTL explained relatively large contributions of 20 to 30% and were confirmed in a near-isogenic background. These findings revealed the importance of water-conservation SW mechanism in yield protection under drought and provided genetic resources for improving drought tolerance in early MG soybeans.