2024/09/14 by Xiuting Hua, Huihong Shi, Zhuang Gui +29 · 6 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · Chemistry · #Biochemical and biochemical processes #Biology #Biotechnology #Botany #Chemistry #GABA and Rice Research #Microbial Metabolic Engineering and Bioproduction #Physics #Primary (astronomy)
paper · doi:10.1093/plphys/kiae455
published in PLANT PHYSIOLOGY 196(4), 2685-2700 (Oxford University Press)
openalex publication_date 2024/09/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In agronomically important C4 grasses, efficient CO2 delivery to Rubisco is facilitated by NADP-malic enzyme (C4NADP-ME), which decarboxylates malate in bundle sheath cells. However, understanding the molecular regulation of the C4NADP-ME gene in sugarcane (Saccharum spp.) is hindered by its complex genetic background. Enzymatic activity assays demonstrated that decarboxylation in sugarcane Saccharum spontaneum predominantly relies on the NADP-ME pathway, similar to sorghum (Sorghum bicolor) and maize (Zea mays). Comparative genomics analysis revealed the recruitment of 8 core C4 shuttle genes, including C4NADP-ME (SsC4NADP-ME2), in the C4 pathway of sugarcane. Contrasting to sorghum and maize, the expression of SsC4NADP-ME2 in sugarcane is regulated by different transcription factors (TFs). We propose a gene regulatory network for SsC4NADP-ME2, involving candidate TFs identified through gene coexpression analysis and yeast 1-hybrid experiment. Among these, ABA INSENSITIVE5 (ABI5) was validated as the predominant regulator of SsC4NADP-ME2 expression, binding to a G-box within its promoter region. Interestingly, the core element ACGT within the regulatory G-box was conserved in sugarcane, sorghum, maize, and rice (Oryza sativa), suggesting an ancient regulatory code utilized in C4 photosynthesis. This study offers insights into SsC4NADP-ME2 regulation, crucial for optimizing sugarcane as a bioenergy crop.