Sugar accumulation enhancement in sorghum stem is associated with reduced reproductive sink strength and increased phloem unloading activity

Frontiers in Plant Science

Plant Science

Stephen Moose¹  Gabriel Beuchat²  Jiang Wang²  Ya-Chi Yu²  Li-Qing Chen²  Xueyi Xue³  Jin Chen⁴ 

[1]Department of Energy (DOE) Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, United States

[2]Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States

[3]Department of Energy (DOE) Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, United States

[4]Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States

[5]Department of Energy (DOE) Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, United States

[6]Institute for Sustainability, Energy, and Environment, University of Illinois at Urbana-Champaign, Urbana, IL, United States

[7]Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States

[8]Institute for Biomedical Informatics, University of Kentucky, Lexington, KY, United States

关键词: sorghum;    sugar accumulation;    SWEETs;    Dry;    bHLH093;    sink strength;    phloem unloading;    sugar transporter;   

DOI  :  10.3389/fpls.2023.1233813

 received in 2023-06-02, accepted in 2023-08-21,  发布年份 2023

来源: Frontiers

【 摘 要 】

Sweet sorghum has emerged as a promising source of bioenergy mainly due to its high biomass and high soluble sugar yield in stems. Studies have shown that loss-of-function Dry locus alleles have been selected during sweet sorghum domestication, and decapitation can further boost sugar accumulation in sweet sorghum, indicating that the potential for improving sugar yields is yet to be fully realized. To maximize sugar accumulation, it is essential to gain a better understanding of the mechanism underlying the massive accumulation of soluble sugars in sweet sorghum stems in addition to the Dry locus. We performed a transcriptomic analysis upon decapitation of near-isogenic lines for mutant (d, juicy stems, and green leaf midrib) and functional (D, dry stems and white leaf midrib) alleles at the Dry locus. Our analysis revealed that decapitation suppressed photosynthesis in leaves, but accelerated starch metabolic processes in stems. SbbHLH093 negatively correlates with sugar levels supported by genotypes (DD vs. dd), treatments (control vs. decapitation), and developmental stages post anthesis (3d vs.10d). D locus gene SbNAC074A and other programmed cell death-related genes were downregulated by decapitation, while sugar transporter-encoding gene SbSWEET1A was induced. Both SbSWEET1A and Invertase 5 were detected in phloem companion cells by RNA in situ assay. Loss of the SbbHLH093 homolog, AtbHLH093, in Arabidopsis led to a sugar accumulation increase. This study provides new insights into sugar accumulation enhancement in bioenergy crops, which can be potentially achieved by reducing reproductive sink strength and enhancing phloem unloading.

【 授权许可】

Unknown   
Copyright © 2023 Xue, Beuchat, Wang, Yu, Moose, Chen and Chen