Study Of Responses In Stipa Breviflora To Gazing On Transcriptome And Genetic Diversity

Biodiversity is the material basis for human survival and sustainable development.Genetic diversity as the core of biological diversity,is not only the result of adapting to the environment in the process of evolution,but also the potence for a support of population in the future.Therefore exploring the mechanism of formation and maintaining of the genetic diversity has very important theoretical and practical significance for the protection and utilization of biological resources,and the recovery of function and services of the damaged ecosystem.Stipa breviflora belongs to the genus Stipa of the genus Gramineae.It is a constructive species of the desert steppe and has high feeding and ecological value.In this study,Illumina sequencing technology was used to carry out transcriptome sequencing of Stipa breviflora under grazing conditions and non-grazing conditions.Then,based on the above gene,SSR primers were developed,and the effects of grazing on the genetic diversity and genetic differentiation of the Stipa breviflora population were investigated with grazing and non-grazing population as the target.The results not only enrich the understanding of the genetic diversity of grassland plants,but also help to protect and develop grassland resources reasonably.The main results are as follows:1.A total of 111018 Unigenes were sequenced in the transcriptional group.Among them,there were 113 significant genes related to grazing,including 68 with upward adjustment and 49 with downward adjustment.In the GO functional classification,there were 22,732 and 24,708 GO items with the most “catalytic activity” and “binding”-enriched DEGs,respectively.In the results of KEGG pathway annotation,63044 Unigenes were annotated to 21 metabolic pathways.2.4 genes in the transcriptional database were randomly selected: salicylic acid binding protein,polyphenol oxidase,shikometate-O-hydroxyl cinnamyl transferase and indole 3 glycerol synthase.The results showed that the down-regulation trend of the four genes was consistent with the transcriptome sequencing results,indicating that the transcriptome sequencing results are reliable.3.The sequencing data of the analysis transcriptional group found that grazing caused the plant defense gene to be active,the oxidase gene and the key enzyme gene of the salicylic acid pathway were up-regulated,and the gene expression related to the hormone showed obvious changes,the expression of jasmonic acid and abscisic acid increased,and the expression of ethylene and cytokinin decreased;in addition,the amount of gene expression related to glucose metabolism and lipid metabolism also changed significantly.It shows that during the process of grazing,herbivores directly damage the plants,such as feeding and trampling,and stimulate the self-protection and metabolism of the plants.4.The SSR primers were developed from the selected differentially expressed genes related to grazing.The results showed that 9 genes associated with grazing have SSR polymorphisms.5.The genetic diversity analysis by SSR molecular markers showed that the number of alleles and richness of the grazing plots were higher than that in the nongrazing plots,and the grazing plots and the non-grazing plots were clearly divided into two groups.It indicates that the direct effect of grazing activity will increase the genetic diversity of Stipa breviflora by changing the gene sequence and promote the differentiation of population genetic structure.The above results have deepened the understanding of the mechanisms of grazing on the genetic diversity of plants.