| Lentinula edodes,also known as champignons,mushrooms,is a kind of important edible and medicinal fungi widely cultivated in Asia.Lentinan is a macromolecule glucan extracted and purified from the mycelium or fruiting body of Lentinula edodes.As the main bioactive substance of Lentinula edodes,lentian has many bioactivities,such as improving immunity,lowering cholesterol and anti-virus.Since the 1980s,scholars from all over the world have carried out in-depth studies on lentinan,including the extraction,purification,chemical structure,physicochemical properties,biological activity and mechanism of lentinan.However,few studies have been conducted on the factors affecting the content of lentinan before harvesting and the key enzyme genes of lentinan metabolism.This paper studies the influence of different varieties,bud number,formula,and growth stages on the polysaccharides content of Lentinula edodes fruiting body,at the same time use different growth stages of Lentinula edodes fruiting body as the experimental material,polysaccharides components were obtained by fractional alcohol precipitation,testing its molecular weight distribution,monosaccharide composition and in vitro immune activity,and the enzyme genes related to lentinan metabolism were mined by transcriptome technique.(1)There were significant differences in polysaccharides content among different varieties,1504 had the highest polysaccharide content,12.97%,25 had the high polysaccharide content,10.57%,and 9 had the lowest polysaccharide content.Among the67 varieties,55 varieties concentrated in 5.64-7.97%and 12 varieties greater than 7.97%.(2)With the increase of Lentinula edodes bud number,the yield showed an increasing trend,while the polysaccharide content of fruiting body showed a decreasing trend.The yield of bud number 35 was the highest,315.32 g/pack,the yield of bud number 5 was the lowest,127.35 g/pack,the polysaccharide content of bud number 5 was the highest,5.10%,and the polysaccharide content of bud number 45 was the lowest,4.26%.(3)Basic culture medium with different proportion of bagasse,sugar beet and sugar has influence on polysaccharides content of Lentinula edodes fruiting body,and among them,add 20%bagasse polysaccharide content increased by 30.59%,with 30%sugar polysaccharide content increased by 26.78%,adding 10%sugar content increased by22.03%,but the single pack production all have varying degrees of decline.(4)The content of crude polysaccharides in fruiting bodies of Lentinula edodes at different growth stages increased first and then decreased.The content of polysaccharide in fruiting bodies of Lentinula edodes at mature stage were the highest,8.97%,the lowest at button stage,4.88%,and there was no significant difference in the contents of polysaccharide at gill-formation stage and harvesting stage.(5)The molecular weight of polysaccharide with 30%component was between 4.099×10~6-1.027×10~7 Da,the molecular weight of polysaccharide with 50%component was between 2.571×10~5-7.834×10~7 Da,and the molecular weight of polysaccharide with 70%component was between 2.298×10~4-2.300×10~5 Da.(6)The monosaccharide components of the polysaccharides obtained at the concentration of three kinds of alcohol precipitation all contain four kinds of monosaccharides:fructose,galactose,glucose and mannose.The monosaccharides of the polysaccharide obtained at 70%also contain glucosamine.Glucose accounts for the largest proportion of all polysaccharides.(7)The polysaccharide obtained from the fruiting body of Lentinula edodes at different growth stages had the activity of stimulating macrophages to release NO in vitro,and the activity of 30%polysaccharides was higher than 50%and 70%on the whole.The activity of 30%polysaccharides at the opening stage was the highest,and the activity of50%and 70%at the mature stage polysaccharides was the highest.(8)Enzymes and genes related to polysaccharides metabolism were screened out,including glucanβ-1,3-glucosidase(GG),β-1,3-glucan synthase(GS1,GS2),UDP-glucose pyrophosphosphprylase(UGP),phosphoglucomutase(PGM),and glucose-6-phosphate isomerase(PGI).(9)GS1 and GS2 gene expressions were up-regulated in the harvest stage,and down-regulated in the opening stage;gg expressions were up-regulated in the opening stage.UGP,PGM and PGI expressions were up-regulated in the late development period.Different varieties,number of buds,formula and growth stages all had significant effects on the polysaccharides content of fruiting bodies of Lentinula edodes.The molecular weight distribution and monosaccharide components of polysaccharides obtained from Lentinula edodes fruiting bodies were significantly different at different growth stages,and all of them had the activity of stimulating macrophages to produce NO in vitro.Theβ-1,3-glucan synthase gene and glucanβ-1,3-glucosidase gene are closely related to synthesis and degradation of polysaccharides.The results of this study provide a theoretical basis for the cultivation and storage of Lentinula edodes and the preparation and products of lentinan. |
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