Coordinated carbon–nitrogen metabolism and hormonal signaling during sugarcane tiller bud elongation: a multi-omics perspective

Abstract Background The development of tillers into productive stalks directly determines sugarcane yield, and tiller bud elongation is a critical process that dictates tiller fate; however, the molecular mechanisms underlying this key phenotypic transition remain poorly understood. In this study, histological observations were performed on tiller buds at the initiation stage (G1, 0.5 cm) and elongation stage (G2, 5 cm), and integrated transcriptomic, proteomic, and metabolomic analyses were conducted to dissect the regulatory machinery governing tiller bud elongation. Results Histological observations revealed that cell proliferation, vascular differentiation, establishment of a functional vascular system, and differentiation of plastids into chloroplasts constitute the cytological foundation driving tiller bud elongation. Integrated transcriptomic and proteomic analysis uncovered systematic reprogramming of carbon–nitrogen metabolism in tiller bud cells: amino acids and their derivatives accumulated significantly at the G2 stage, characterized by activation and enhancement of the photosynthetic carbon fixation pathway and rapid export of carbon skeletons to drive the massive accumulation of amino acids and proteases. Further integration with metabolomic data demonstrated that phytohormones are broadly involved in regulating tiller bud elongation: downregulation of the key strigolactone biosynthetic gene CCD8A restricted strigolactone production; similarly, jasmonic acid content declined, whereas auxin and salicylic acid contents increased. Meanwhile, the sucrose–trehalose-6-phosphate (Tre6P) signaling pathway was strongly activated, and the abundant accumulation of sucrose and Tre6P was significantly positively correlated with the expression of six genes, including MAPKKK3 . Conclusion These findings suggest that hormonal signaling acts in concert with carbon–nitrogen metabolism to regulate the elongation growth of sugarcane tiller buds. The key genes PEPC , PPDK , FBA , and CCD8A may serve as candidate genes for improving tillering traits in sugarcane.