Screening The Aroma-promoting Fungi Of Aquilaria Sinensis(Lour.) Gilg And Development Of Agarwood Inducer

Aquilaria sinensis(Lour.)Gilg is a plant of the Thymelaeaceae genus Aquilaria.It is the main scent-producing tree species and economic tree species in my country,with extremely high economic value and medicinal value;However,the unharmed white wood incense will not produce agarwood under natural conditions.However,the formation period of agarwood is too long by using the traditional method of forming incense.Therefore,this study screened out the endogenous aroma-promoting fungi that can promote aroma-setting of white woody from the scented parts of white wood,and used single-factor fermentation test to determine the most suitable growth conditions.The aroma-promoting fungi were combined with sodium chloride.Reagents are compounded into fungal aroma-promoting inducers,and efficient agarwood inducers are screened through the defensive reaction caused by the inducer and the color change of the tree,so as to achieve the purpose of green and efficient aroma-setting,and provide a sustainable development for the agarwood industry Scientific basis and theoretical basis.The main research results are reported as follows:(1)Screening and identification of agarwood endogenous fragrant fungiIn this study,34 strains of endophytic fungi were preliminarily isolated from the xylem of agarwood,which were preliminarily divided into 2 unclassified fungi in 9 genera and 15,and the 6 fungi with the best infection effects on the tree were screened out through live re-screening(CX-1-1,CX-G-3-2,CX-1-2,CX-G-2-2,CX-1-5 and CX-C3-1).The growth rate measurement,morphological observation,and three-gene molecular identification of the six fragrance-promoting fungi were carried out.The identification results showed that:CX-1-1 is Fusarium oxysporum,CX-1-2 is Fusarium fujikuroi,CX-G-2-2 is Fusarium proliferatum,CX-G-3-2 is Fusarium solani,CX-1-5 is Lasiodiplodia pseudotheobromae and CX-C3-1 is Lasiodiplodia theobromae.(2)Optimization of fermentation conditions for agarwood aroma-bearing fungiThe fermentation optimization of 6 kinds of aroma-promoting fungi was carried out by single factor experiment,and the results obtained:the best culture days of Fusarium spp.and Lasiodiplodia spp.were 4d and 9d;The results of light conditions showed that the four strains of F.oxysporum,F.proliferatum,L.pseudotheobromae and L.theobromae were fragrant.The fungus produces the most spores under the rotation of light and dark,while the spore production of F.fujikuroi and F.solani is the most under the culture conditions of all-day light.The optimum temperature for fragrant-bearing fungi of the genus Fusarium spp.and Lasiodiplodia spp is 28℃ and 30℃;the fragrant fungi prefer alkaline growth environment,the optimum initial pH of the medium is 8,and the optimum shaker speed for fragrant fungi is 180r/min or 200r/min;the best addition amount of NaCl and CaC12 is 2g;the best effect of agarwood inducing substrate is 3 g.(3)Development and application of agarwood inducer6 kinds of non-antagonistic aroma-stimulating fungi and NaCl and CaCl2 substances were developed into 3 inducers with different ratios.After Bai Muxiang received inducer treatment,treatment group 3(F.solani:F.fujikuroi:F.oxysporum:F.proliferatum:L.pseudotheobromae:L.theobromae=1:1:1:1:1:1)caused The enzyme activity of the defensive reaction of Aquilaria tree is the most obvious,reaching the peak on the 7th day,the PAL activity is 44.7 U·g-1·min-1,the POD enzyme activity is 871.3 U·g-1·min-1,and the SOD is 568 U·g-1·min-1,MDA content is 16.4 mmol·g-1.The brown variation range is treatment 3>treatment 2>treatment 1>CK;the brown material is burned to find that it emits white smoke and is accompanied by a certain sweet fragrance;the best agarwood inducer combination is determined as treatment group 3.The microscopic results of the brown-changed wood after 5 months of treatment with treatment 3 and the increased amount showed that Agarwood is a diffuse porous wood with inconspicuous growth rings;there are more connotative phloem,island-like,more uniform distribution,and darker color.Black or brown,there is accumulation of yellowish-brown oily substance in wood rays and part of the duct;the cross-section of the duct is oval,round or irregular with multiple angles,3-4 juxtaposed,wood fibers are mostly 4-6 angles Polygonal shape,thin wall;wood ray cells are longer,the cross section is mainly a single row of single cells,and a few wood rays are distributed around the catheter;However,no intrusion bodies and crystals were observed in the catheters and wood rays.The staining identification result of the alcohol-soluble extract of the brown-changing wood is fuchsia.