硒对云南白灵芝生长、品质及DNA甲基化特征的影响

Effects of Selenium on Growth,Quality and DNA Methylation of Ganoderma leucocontextum from Yunnan

采用田间覆土栽培试验,设置6个Se浓度(0、50、100、200、300、400μg/g)处理,分别记为CK、Se50、Se100、Se200、Se300、Se400,研究外源硒对云南白灵芝生长发育、重金属积累、生物活性成分含量及其DNA甲基化特征的影响。结果表明,与CK相比,外源Se对子实体柄长和菌盖大小(横径、纵径)无显著影响,但能显著降低菌盖厚度;随着Se施用水平提高,菌丝生长速率和子实体硒含量均呈先增后降的趋势,生物量呈先降后增再降的趋势。子实体重金属含量(As、Cd、Pb、Hg)随Se浓度增加呈持续降低趋势,线性分析也表明,重金属含量与Se施用浓度均呈显著负相关。施Se增加了子实体多糖、粗蛋白、黄酮及总氨基酸含量,其中,多糖、黄酮含量在Se400处理下最高,总氨基酸、粗蛋白含量分别在Se200、Se300处理下最高。HPLC测定分析表明,与CK相比,Se300提高了灵芝酸A、灵芝酸DM、灵芝酸F及灵芝酮三醇为主的三萜酸组分,其总三萜酸含量较其他处理提高2.93%~25.54%。敏感扩增多态性分析(MSAP)结果显示,Se300较CK、Se400相比具有较高的未甲基化位点比例和较低的甲基化位点比例。综上,施用外源硒可促进早期菌丝生长,提高子实体生物量累积,改善子实体重金属安全性能和生物活性成分品质,改变DNA甲基化比例,且以300μg/g施用浓度的整体效果最佳,其子实体产量较对照显著提高11.36%。

A field soil-covering cultivation experiment was conducted with six senium(Se)treatments(0,50,100,200,300,400μg/g),which were designated as CK,Se50,Se100,Se200,Se300 andSe400,to study the effects of exogenous Se on growth and development,heavy metal accumulation,contentsof bioactive components and DNA methylation characteristics of Yunnan Ganoderma leucocontextum.The results showed that compared with CK,exogenous Se had no significant impacts on length of fruiting body stalkand size of mushroom cap(both horizontal and vertical diameters),but decreased the thickness of mushroomcap significantly.With the increase of Se application level,the growth rate of mycelium and the Se content in fruiting bodies increased initially and then decreased,while the biomass showed a trend of initial decreasing,subsequent increasing,and then decreasing again.The content of heavy metals(As,Cd,Pb,Hg)in fruitingbodies continuously decreased with the increase of Se concentration.Linear analysis results also indicated thatheavy metal content was significantly negatively correlated with Se application concentration.The application ofSe increased the contents of polysaccharides,crude protein,flavonoids and total amino acids in fruitingbodies,among which,the polysaccharide and flavonoid contents reached the highest level in the Se400 treatment,whereas the highest contents of total amino acids and crude protein were found in the Se200 and Se300treatments,respectively.HPLC analysis results showed that compared with CK,Se300 increased the content oftriterpenoid acid components such as ganoderic acid A,ganoderic acid DM,ganoderic acid F and ganodermanontriol,and the total content of triterpenoid acids increased by 2.93%to 25.54%compared with the othertreatments.The methylation sensitive amplification polymorphism(MSAP)analysis showed that Se300 hadmore unmethylated sites and lower methylation ratios compared to CK and Se400.In summary,the applicationof exogenous Se promoted the mycelial growth at early time,increased the biomass accumulation in fruitingbodies,improved heavy metal safety performance and quality of bioactive components,and altered the DNAmethylation ratio.The overall effect was the best at the Se application concentration of 300μg/g with the yieldsignificantly increased by 11.36%compared with the control treatment.