| As the demand for Gastrodia elata Bl.increases and the wild resources become scarce,artificial cultivation has become a focus of attention.The growth process of Gastrodia elata requires fungal germination and Armillaria mellea to provide nutrients.The quality of these two fungi directly affects the yield and quality of Gastrodia elata.However,the fungal strains used for germination are prone to degradation and inconsistencies in production quality.The growth of Armillaria mellea requires a large amount of fungal material,and traditional planting methods involving extensive logging can lead to severe ecological damage.Therefore,it is necessary to improve the seed germination rate of Gastrodia elata,and to search for alternative cultivation materials.This study aimed to explore different non-biological factors that promote Gastrodia elata seed germination,such as plant hormones and exogenous additives,in order to find germination-promoting substances.The study also aimed to investigate the mechanism by which the germination-promoting substance,Trametenolic acid B(TAB),promotes Gastrodia elata seed germination through transcriptome sequencing,differential gene expression(DEGs)screening,and enrichment analysis.The study also aimed to select suitable alternative fungal materials from the main economic tree waste in the western Hubei region,using the Quercus fabri Hance group as a control and using the growth status of Armillaria mellea,changes in lacquer enzyme activity,and the content of the three main effective components of Armillaria mellea as indicators.The main results are as follows:1.Screening of factors promoting germination of Gastrodia elata seeds: treatment with 1mg/L TAB showed the best effect on seed germination,with the highest germination rate being 5.1 times that of the control group.In addition,the use of 2 mg/L or lower concentration of 2,4-dichlorophenoxyacetic acid(2,4-D)solution,a combination of 2 mg/L 2,4-D and 0.15mg/L or lower concentration of sodium humate(SHA)or 0.3 μmol/L or lower concentration of brassinolide(EBR),treatment with 10 mg/L or lower concentration of TAB,and treatment with 0.1-0.5 mg/L concentration of gibberellin all promoted the germination of Gastrodia elata seeds.However,treatment with zeatin(ZT)at concentrations above 2 mg/L,potato juice,coconut juice,and banana juice at concentrations above 150 g/L inhibited seed germination(P< 0.05).The acetic ether fraction of Mycena dendrobii and Trametes lactinea mycelium extracts promoted the germination of Gastrodia elata seeds more effectively than other polar fractions.2.Transcriptomic experiment on the effect of TAB on seed germination of Gastrodia elata: 25 differentially expressed genes were preliminarily screened as candidate genes,including 4 genes related to plant-pathogen interactions,7 genes related to key enzymes in lignin synthesis pathways,6 genes related to transcription factors regulating lignin synthesis,5 genes related to key enzymes in abscisic acid synthesis and metabolism,and 3 differentially expressed genes related to key enzymes in gibberellin synthesis.However,further research and verification are needed to determine whether these genes are the key genes responsible for the promotion of symbiotic germination of Gastrodia elata seeds by TAB treatment.3.Screening experiment of Culture Substitute for Gastrodia elata: The main agricultural and forestry wastes in the western Hubei area were screened preliminarily.The results showed that Malus hupehensis(Pamp.)Rehd.is more suitable as a substitute fungi for the cultivation of Gastrodia elata in various indicators similar to Quercus fabri Hance,and the results of simulated wild cultivation experiments showed that the branches of Malus hupehensis(Pamp.)Rehd.are suitable for the cultivation of Gastrodia elata with good yield and quality.Other tree branches such as Morus alba L.,Juglans regia L.,Camellia sinensis(L.)O.Ktze.,and Magnolia wufengensis L.Y.Ma et L.R.Wang can also be used as substitute fungi or main materials for Armillaria mellea fungus bags. |
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