Thornbury Brittany Clare, He Tianhua, Jia Yong, Li Chengdao
Western Crop Genetics Alliance, College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.
Western Australian State Agricultural Biotechnology Centre, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.
Int J Mol Sci. 2025 Aug 1;26(15):7424. doi: 10.3390/ijms26157424.
Ribulose bisphosphate carboxylase (RuBisCO) is the primary regulator of carbon fixation in the plant kingdom. Although the large subunit (RBCL) is the site of catalysis, RuBisCO efficiency is also influenced by the sequence divergence of the small subunit (RBCS). This project compared the RBCS gene family in C3 and C4 grasses to identify genetic targets for improved crop photosynthesis. / phylogeny groups exhibited a syntenic tandem duplication array averaging 326.1 Kbp on ancestral chromosomes 2 and 3, with additional copies on other chromosomes. Promoter analysis revealed a paired I-box element promoter arrangement in chromosome 5 RBCS of , , and . The I-box pair was associated with significantly enhanced expression, suggesting functional adaptation of specific RBCS gene copies in . -derived pan-transcriptome data showed that RBCS expression was 50.32% and 28.44% higher in winter-type accessions compared to spring types for coleoptile ( < 0.05) and shoot, respectively ( < 0.01). Molecular dynamics simulations of a mutant Rubisco carrying a C4-like amino acid substitution (G59C) in RBCS significantly enhanced the stability of the Rubisco complex. Given the known structural efficiency of C4 Rubisco complexes, G59C could serve as an engineering target for enhanced RBCS in economically crucial crop species which, in comparison, possess less efficient Rubisco complexes.
核酮糖-1,5-二磷酸羧化酶（RuBisCO）是植物界碳固定的主要调节因子。尽管大亚基（RBCL）是催化位点，但RuBisCO的效率也受小亚基（RBCS）序列差异的影响。该项目比较了C3和C4禾本科植物中的RBCS基因家族，以确定改善作物光合作用的遗传靶点。系统发育组在祖先染色体2和3上表现出平均长度为326.1千碱基对的同线串联重复阵列，在其他染色体上还有额外的拷贝。启动子分析揭示了在[具体植物名称1]、[具体植物名称2]和[具体植物名称3]的第5号染色体RBCS中存在一对I-box元件启动子排列。该I-box对与显著增强的表达相关，表明[具体植物名称]中特定RBCS基因拷贝的功能适应性。[具体植物名称]来源的泛转录组数据显示，与春季类型相比，冬季类型幼苗（P < 0.05）和地上部（P < 0.01）的RBCS表达分别高50.32%和28.44%。对在RBCS中携带C4样氨基酸取代（G59C）的突变型Rubisco进行分子动力学模拟，显著增强了Rubisco复合物的稳定性。鉴于已知C4 Rubisco复合物的结构效率，G59C可作为经济上重要作物物种中增强RBCS的工程靶点，相比之下，这些作物物种的Rubisco复合物效率较低。
