Abstract
sugary enhancer1 (se1) is a naturally occurring mutant allele involved in starch metabolism in maize endosperm. It is a recessive modifier of sugary1 (su1) and commercially important in modern sweet corn breeding, but its molecular identity and mode of action remain unknown. Here, we developed a pair of near-isogenic lines, W822Gse (su1-ref/su1-ref se1/se1) and W822GSe (su1-ref/su1-ref Se1/Se1), that Mendelize the se1 phenotype in an su1-ref background. W822Gse kernels have lower starch and higher water soluble polysaccharide and sugars than W822GSe kernels. Using high-resolution genetic mapping, we found that wild-type Se1 is a gene Zm00001d007657 on chromosome 2 and a deletion of this gene causes the se1 phenotype. Comparative metabolic profiling of seed tissue between these 2 isolines revealed the remarkable difference in carbohydrate metabolism, with sucrose and maltose highly accumulated in the mutant. Se1 is predominantly expressed in the endosperm, with low expression in leaf and root tissues. Differential expression analysis identified genes enriched in both starch biosynthesis and degradation processes, indicating a pleiotropic regulatory effect of se1. Repressed expression of Se1 and Su1 in RNA interference-mediated transgenic maize validates that deletion of the gene identified as Se1 is a true causal gene responsible for the se1 phenotype. The findings contribute to our understanding of starch metabolism in cereal crops.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 20776-20785 |
| Number of pages | 10 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 116 |
| Issue number | 41 |
| DOIs | |
| State | Published - Oct 8 2019 |
Bibliographical note
Funding Information:ACKNOWLEDGMENTS. We acknowledge the support of a National Research Initiative grant from the US Department of Agriculture Cooperative State Research, Education and Extension Service (CSREES/NRI 2007-55301-18179) and the Wisconsin Alumni Research Foundation Accelerator Program. We thank Rajan Sekhon for help with expression analysis and Nick Santoro for leaf carbohydrate processing. We thank the University of Wisconsin Biotechnology Center DNA Sequencing Facility for providing RNA-seq services. Mass spectrometry was performed by the Proteomics and Metabolomics Facility (Colorado State University). Research materials were grown at the University of Wisconsin Agricultural Research Stations (ARSs), and we specifically acknowledge assistance of Tom Wright at the West Madison ARS and Lynn Hummel at the ARS greenhouses.
Funding Information:
We acknowledge the support of a National Research Initiative grant from the US Department of Agriculture Cooperative State Research, Education and Extension Service (CSREES/NRI 2007-55301-18179) and the Wisconsin Alumni Research Foundation Accelerator Program. We thank Rajan Sekhon for help with expression analysis and Nick Santoro for leaf carbohydrate processing. We thank the University of Wisconsin Biotechnology Center DNA Sequencing Facility for providing RNA-seq services. Mass spectrometry was performed by the Proteomics and Metabolomics Facility (Colorado State University). Research materials were grown at the University of Wisconsin Agricultural Research Stations (ARSs), and we specifically acknowledge assistance of Tom Wright at the West Madison ARS and Lynn Hummel at the ARS greenhouses.
Publisher Copyright:
© 2019 National Academy of Sciences. All rights reserved.
Keywords
- Maize
- Starch metabolism
- Sugary enhancer1
- Sugary1