Fujian Province Key Laboratory of Haixia Applied Plant Systems Biology, Center for Genomics and Biotechnology, National Sugarcane Engineering Technology Research Center, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Sugarcane Biology, Guangxi University, Guangxi, 530004, China.
Plant J. 2023 Mar;113(6):1278-1294. doi: 10.1111/tpj.16110. Epub 2023 Feb 4.
Saccharum spontaneum and Saccharum officinarum contributed to the genetic background of modern sugarcane cultivars. Saccharum spontaneum has shown a higher net photosynthetic rate and lower soluble sugar than S. officinarum. Here, we analyzed 198 RNA-sequencing samples to investigate the molecular mechanisms for the divergences of photosynthesis and sugar accumulation between the two Saccharum species. We constructed gene co-expression networks based on differentially expressed genes (DEGs) both for leaf developmental gradients and diurnal rhythm. Our results suggested that the divergence of sugar accumulation may be attributed to the enrichment of major carbohydrate metabolism and the oxidative pentose phosphate pathway. Compared with S. officinarum, S. spontaneum DEGs showed a high enrichment of photosynthesis and contained more complex regulation of photosynthesis-related genes. Noticeably, S. spontaneum lacked gene interactions with sulfur assimilation stimulated by photorespiration. In S. spontaneum, core genes related to clock and photorespiration displayed a sensitive regulation by the diurnal rhythm and phase-shift. Small subunit of Rubisco (RBCS) displayed higher expression in the source tissues of S. spontaneum. Additionally, it was more sensitive under a diurnal rhythm, and had more complex gene networks than that in S. officinarum. This indicates that the differential regulation of RBCS Rubisco contributed to photosynthesis capacity divergence in both Saccharum species.
野生甘蔗和栽培甘蔗为现代甘蔗品种的遗传背景做出了贡献。野生甘蔗的净光合速率高于栽培甘蔗，而可溶性糖含量则低于栽培甘蔗。在这里，我们分析了 198 个 RNA-seq 样本，以研究这两个甘蔗物种在光合作用和糖积累方面差异的分子机制。我们基于叶片发育梯度和昼夜节律的差异表达基因 (DEG) 构建了基因共表达网络。我们的结果表明，糖积累的差异可能归因于主要碳水化合物代谢和氧化戊糖磷酸途径的富集。与栽培甘蔗相比，野生甘蔗 DEGs 中光合作用相关基因的富集程度更高，对光合作用相关基因的调控也更为复杂。值得注意的是，野生甘蔗缺乏光合作用与光呼吸刺激的硫同化之间的基因相互作用。在野生甘蔗中，与时钟和光呼吸相关的核心基因对昼夜节律和相位移动表现出敏感的调控。小亚基 Rubisco (RBCS) 在野生甘蔗的源组织中表达水平更高。此外，它在昼夜节律下更为敏感，并且与栽培甘蔗相比，其基因网络更为复杂。这表明 RBCS Rubisco 的差异调控导致了这两个甘蔗物种光合作用能力的差异。
