Effects Of Chitooligosaccharides On Alkaloid Accumulation In Catharanthus Roseus

Chitooligosaccharides are the only basic aminooligosaccharides with positively charged cations in nature,which have a significant impact on regulating plant growth and improving the original antioxidant properties.In order to study the effect of chitooligosaccharides on the accumulation of vinca alkaloid,the treatment of Catharanthus roseus with different concentrations and different molecular weight chitosan was used to detect the changes of physiological characteristics,the alkaloid content in leaves and the antioxidant enzymes.The effect of activity and the relative expression of key genes in the vinca alkaloid synthesis pathway after chitooligosaccharides treatment,and the effect of chitooligosaccharides on the accumulation of vinca alkaloids was evaluated.In the initial stage of the experiment,the effects of different treatments on the alkaloid synthesis in Catharanthus roseus were studied.The seeds were soaked in chitooligosaccharides solution and sprayed with sugar,sprayed water or directly sprayed vinca flower in water to carry out experiments.Content of vindoline and vinblastine was analyzed as experimental data when the final leaves matured.Compared with the control,Catharanthus roseus species immersed in demonized water had a significant increase in vinca alkaloids treated with chitooligosaccharides every five days,with an increase of up to 88%.Chitooligosaccharides with molecular weight of 1000 Da,2000Da,and 3000 Da were selected,and four concentrations of 0.01 ?g/m L,0.1 ?g/m L,1 ?g/m L,and 10 ?g/m L were designed for each molecular weight.The results showed that chitooligosaccharides could significantly increase the growth index of vinca,and the most significant treatment was achieved with 3000 Da chitooligosaccharides 0.01 ?g/m L.Report to the control,the root length increased by 66.57% and the plant height increased by 75.18%.The root weight,stem weight and leaf weight increased by 167.32%,259.41% and 137.17%,respectively.With the increase of chitooligosaccharides concentration,the content of alkaloids in leaves increased first and then decreased,and the content increased with the concentration of 3000 Da chitosan 0.1 ?g/m L.The vindoline content increased by 60.52%;the vinblastine increased by 147.72%.To investigate the effects of chitooligosaccharides on the antioxidant capacity of vinca,catalase,superoxide dismutase,peroxidase,ascorbate peroxidase and glutathione in leaves of periwinkle after treatment with chitosan oligosaccharides The active content of the reductase was measured.The results showed that chitosan oligosaccharide could increase the content of various antioxidant enzymes in the leaves of Catharanthus roseus,and the activity of catalase and glutathione reductase in the leaves of Catharanthus roseus was 0.1 ?g/m L.The sugar treatment increased by 109.62% and 141.37% respectively;the activities of superoxide dismutase,peroxidase and ascorbate peroxidase were also significantly improved after chitooligosaccharides treatment.This paper is to study the effect of chitooligosaccharides on the synthesis of vinca alkaloids.According to the metabolic pathway of vinca alkaloids,nine key enzyme genes(SLS,STR,SGD,T16 H,PRXL,ORCA3,G10 H,DAT,D4H)were selected.Real-time quantitative PCR was utilized to detect the relative expression of key genes in the metabolic pathway of chitooligosaccharides treated with chitooligosaccharides at different concentrations.It was noted that a 3000 molecular weight chitooligosaccharides at a concentration of 0.1 ?g/m L can maximize the expression level of the gene.The results showed that chitooligosaccharides could regulate the accumulation of vinca alkaloids.0.1 ?g/m L chitooligosaccharides with molecular weight of 3000 could significantly improve the growth indexes of vinca,and improve the vindoline and vinblastine of Catharanthus roseus.The content of chitooligosaccharides can also significantly increase the activity of various antioxidant enzymes in the leaves of Catharanthus roseus,and detect the expression of related genes in the metabolic pathway of vinca alkaloids.It is found that vinca alkaloids is regulated by regulating the expression of genes related to alkaloid synthesis.Promote the effect of alkaloid accumulation.