A novel allele of Sh1 facilitates the development of waxy-sweet corn from waxy corn.

Authors

Ling Zhou, Lihua Ning, Shuaiqiang Liang, Qiaoqiang Hu, Wenxiang Zhang, Yuxin Pan, Zhifang Gao, Jun Hong, Yuancong Wang, Wenming Zhao, Yanping Chen, Huixue Dai, Han Zhao

Published in

Plant physiology. Aug 17, 2026. Epub Aug 17, 2026.

Abstract

Waxy corn and sweet corn represent two major classes of fresh-eating corn, and each with distinct sensory attributes and nutritional compositions. Developing a new variety that combines both waxy and sweet traits would address rising consumer demand and expand new market potential. From a fast neutron-mutagenized population of the waxy corn inbred line HB522, we isolated a novel mutant, designated as wx-sweet, whose kernels simultaneously exhibit waxy and sweet characteristics at the milk-filling stage. Through bulked segregant analysis (BSA) combined with fine mapping, we mapped the causal locus to SHRUNKEN1 (Sh1) on chromosome 9, which was confirmed by an allelism test with a characterized Mu-insertion allele of Sh1. A 7,227-bp Copia-type LTR retrotransposon insertion was identified in exon 2 of Sh1 in the wx-sweet mutant by long-read sequencing. Consistently, the novel sh1 allele significantly reduced sucrose synthase activity. Genetic and physiological analyses demonstrate that sh1 and wx1 act synergistically to fine-tune carbohydrate metabolism in the endosperm. Integrated transcriptomic and metabolomic profiling uncover extensive transcriptional reprogramming and redirected metabolic flux, leading to substantial accumulation of sucrose and a range of oligosaccharides. These metabolic shifts underlie the unique simultaneous dual waxy-sweet texture in fresh-eating wx-sweet kernels. In summary, our work not only provides valuable genetic resources for breeding next-generation fresh-eating corn, but also, for the first time, elucidates the molecular mechanism by which the sh1 and wx1 mutation cooperatively shape the waxy-sweet endosperm phenotype.

PMID:
42607135
Bibliographic data and abstract were imported from PubMed on 18 Aug 2026.

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