| Dendrobium officinale Kimura et Migo has very high medicinal value.Naturally grown D.officinale symbiosis with fungi and form mycorrhizas.Fungi have an extremely important influence on the growth and development of D.officinale and the accumulation of biologically active substances.The symbiosis and symbiosis mechanism of D.officinale and fungi are hot trends today.However,previous studies mostly focused on observing the effect of a single fungus on D.officinale,but no effect on D.officinale under the combined action of multiple fungi,and no reports on the differential expression of D.officinale.In this experiment,three fungi isolated from wild D.officinale: Tulasnella sp.,Mycena sp.and Fusarium sp..Four groups were set up in the experiment,three of which consisted of the above-mentioned three kinds of fungi and the tissue culture seedlings of D.officinale.The fourth group was mixed culture of the three kinds of fungi for 30 days.After the symbiosis culture,we found that the fourth group of D.officinale grew the best,with the highest germination rate,fresh weight increase and dry weight increase.In addition,we measured the total polysaccharides,total alkaloids and total flavonoids of D.officinale seedlings in the four experimental groups,and found that compared with the control group,the four experimental groups had significant increases in these three aspects,among which increased The most obvious is the fourth experimental group,the total polysaccharide content reached 87.470mg/g,the alkaloid content reached 4.289mg/g,much higher than the control group,and significantly higher than the other three experimental groups.In recent years,more and more studies have found that circ RNA can be differentially expressed in plants under biotic or abiotic stresses,but there have not been reports about circ RNA in D.officinale.In this experiment,through high-throughput sequencing of D.officinale(experimental group)and sterile seedlings(control group),4115 groups of different circular RNAs were measured in the two groups.Among them,4091 groups were derived from exons,and 24 groups were derived from introns.Compared with the control group,there are 27 types of circ RNAs that are significantly differentially expressed in the experimental group,and all are derived from exons.Among them,17 types of circ RNA are significantly up-regulated and 10 types are significantly down-regulated.GO enrichment analysis detected a total of 99 sets of data,of which the most significant gene was nucleus in the cell component;KEGG enrichment analysis found that there were 7 enrichment pathways in circ RNA,among which,Butanoate metabolism and Mismatch repair had significant differences.After analyzing the differential expression of circ RNA,it was found that the expression of multiple related genes related to cell division and DNA replication in the experimental group was up-regulated.On the contrary,the genes that inhibit cell division were down-regulated,and the significant difference was performed on circ RNA.KEGG enrichment analysis found that the two signal pathways of Mismatch repair and Homologous recombination are enriched,which proves from the genetic level that fungi can stimulate the division and growth of D.officinale cells.In addition,two genes related to the transcription level of D.officinale have also been significantly down-regulated,and Nudix hydrolase 3 gene,which is related to the pathway of pathogen infection in plants,has been significantly up-regulated.The latter proves that the symbiotic fungus infects D.officinale.The way of infecting plants is similar to that of other pathogens.This experiment studies and analyzes D.officinale circ RNA.In order to further study the symbiosis mechanism of D.officinale and fungi in the future,some directions have been explored at the genetic level,and a certain reference basis has been provided,which has certain practical applications. |
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