Plant Cultivation, Physiology & Biochemistry
YAN Ning, WANG Maoyao, LI Xinru, SHEN Yinjuan, LI Ming, ZHANG Muqing, HUANG Jiangfeng
Sugarcane is a crucial crop for both sugar and bioenergy production, with sugar accumulation and cell wall formation being critical biological processes during its growth and development. This study employed transcriptome sequencing on the ROC22 sugarcane variety, collecting samples from leaves at the 1st, 3rd, and 5th nodes, bark tissues at the 3rd, 5th, 7th, 11th, and 17th internodes, and pith tissues at the 1st, 3rd, 5th, 7th, 11th, and 17th internodes. A comprehensive analysis of 42 transcriptome datasets using Weighted Gene Co-expression Network Analysis (WGCNA) revealed 34 distinct co-expression modules. Notably, the midnight blue, purple, and magenta modules demonstrated significant and specific correlations with the 1st node leaf, 7th internode pith, and 5th internode bark, respectively. KEGG and GO enrichment analyses indicated that the modules participated in tissue-specific biological processes. The blue, yellow, turquoise, and black modules were primarily expressed in leaves, young pith, immature internodes, and bark, respectively. Within the blue module, key enzymes implicated in photosynthesis were identified, such as LFNR1, PSAK, PETE, PSAN, and NADP-ME4, which are essential for the initial production and accumulation of sugar in sugarcane. The yellow module featured a sucrose metabolism network centered on SUS4, including SWEET2 and an array of sugar transport-related enzymes and proteins, suggesting that the pith serves as the primary site for sugar transport and storage in sugarcane. The turquoise module contained glycoproteins and enzymes potentially involved in the synthesis and modification of the primary cell wall. Meanwhile, transcription factor NST1, which regulates secondary cell wall biosynthesis, along with other cell wall-modifying enzymes in the black module, may contribute to cell wall deposition in the cortex, providing mechanical strength and a barrier against external stresses for sugarcane. The findings would provide important references for studying the regulatory networks of sugar accumulation and cell wall formation in sugarcane.