Abstract
Background:The characteristics of elephant grass, especially its stem lignocellulose, are of great significance for its quality as feed or other industrial raw materials. Because the genome of elephant grass has not been deciphered, the study of its lignocellulose synthesis pathway and key genes is limited. Results:In this study, RNA sequencing (RNA-seq) combining with lignocellulose content analysis and cell wall morphology observation using elephant grass stems from different development stages as materials, were applied to reveal the genes regulating cellulose and lignin synthesis. A total of 3852 differentially expressed genes (DEGs) were identified in three periods of T1, T2 and T3. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the two most abundant metabolic pathways were phenylpropanemetabolism, starch and sucrose metabolism, which closely related to cell wall development, hemicellulose, lignin and cellulose synthesis. Through weighted gene co-expression network analysis (WGCNA) of DEGs, a ‘blue’ module highly correlated with cellulose synthesis and a ‘turquoise’ module highly correlated with lignin synthesis were exhibited. A total of 43 candidate genes were screened, of which 17 had function annotations in other species. In addition, the expression of CesA, PAL, CAD, C4H, COMT, CCoAMT, F5H, CAD and CCR at different development stages were analyzed, and found that the content of lignocellulose was correlated with the expression levels of these structural genes. Conclusions:This study not only provides new insights into the molecular mechanisms of cellulose and lignin synthesis pathways in elephant grass, but also offers a new and extensive list of candidate genes for more specialized functional studies in the future which may promote the development of high-quality elephant grass varieties with high cellulose and low lignin content.
Genetic differences in digestibility of forage maize hybrids.
