Cell Wall Polysaccharide Metabolism And Quality Changes Of Postharvest Zizania Latifolia

Zizania latifolia is rich in nutrients,but it is hard to store at room temperature,and the postharvest quality is prone to deteriorate.The cell wall components changes in fruits mainly lead to postharvest softening,such as pectin and cellulose.In this study,we evaluated the relationship between the cell wall degrading enzyme activity and the composition of cell wall polysaccharides and studied texture in the postharvest Z.latifolia at different temperatures.We analyzed the differential expression of cell wall polysaccharide-related metabolic genes from the transcriptional level.Providing a scientific basis for inhibiting the postharvest deterioration of Z.latifolia at low-temperature and prolonging the storage time of Z.latifolia.The main findings are as follows:1.Postharvest cell wall components and polysaccharide metabolism of Z.latifolia researchDuring the storage time,the cell wall components of Z.latifolia were gradually accumulated.The cellulose content decreased by 25.5% and 26.6% after storage at 4°C and 25°C for 16 days,respectively.The activities of cell wall polysaccharide metabolism-related enzymes(β-gal,PG,and Cx)were lower during low-temperature storage.Correlation analysis and principal component analysis showed that the hardness of Z.latifolia was related to cell wall composition(protopectin,soluble pectin)and the corresponding enzymatic activity.The contents of protopectin and soluble pectin were negatively correlated with a correlation coefficient of-0.72(p<0.01).2.Separation,purification and characteristic analysis of Z.latifolia cell wall polysaccharides during storageTransmission electron microscopy and histochemical staining observe indicated that polysaccharides gradually aggregated to the secondary wall during storage.The cell wall polysaccharides were distributed unevenly and degraded locally.The water extraction and alcohol precipitation method was used to separate the water-soluble polysaccharides,and the DEAE sepharose fast flow and Sephadex G-100 chromatographic separation were used for purification.Congo red test and scanning electron microscope showed that the polysaccharide of Z.latifolia had a triple helix structure,and the polysaccharide became aggregated during storage.3.Study on differential gene expression and metabolic pathway related to polysaccharide metabolism during storage of Z.latifoliaThe Z.latifolia samples from different storage periods were selected for RNA-seq sequencing.The differentially expressed cell wall metabolism-related genes(Zl PG4,Zl PE3,Zl GUL2 and Zl Cx4)and metabolic pathways were screened through functional annotation and enrichment analysis.Low-temperature storage inhibited the up-regulated expressions of Zl PG4,Zl GUL2 and Zl Cx4,which in turn delayed the degradation of postharvest Z.latifolia cell wall polysaccharides.