一种高富硒平菇的紫外诱变筛选及其营养强化的应用

Screening of a selenium-enriching strain of Pleurotus ostreatus by ultraviolet mutagenesis and its application in nutrient enrichment

摘要:

【背景】食用菌在自然状态下进行富硒培养难以达到硒营养强化的国家标准。【目的】通过紫外诱变技术筛选对硒具有高效富集和转化能力的菌株，以提高其硒含量，为富硒食用菌营养强化剂的产品开发奠定基础。【方法】通过硒抗性筛选，确定诱变的出发菌株，对其紫外辐照诱导发生变异，并根据菌丝生长速率、子实体生物学效率、总硒和有机硒含量综合评估诱变菌株的优良特性。【结果】在硒浓度100 mg/kg和120 mg/kg的袋料栽培基质中诱变菌株120-5菌丝的生长速率分别为1.27 cm/d和1.19 cm/d，子实体总硒量分别为199.77 mg/kg和224.15 mg/kg，有机硒量分别为198.83 mg/kg和223.56 mg/kg，占总硒量99.53%和99.74%，其硒含量均达到了富硒食用菌营养强化剂的国标要求。出发菌株qiu-2020在硒浓度100 mg/kg和120 mg/kg基质中的菌丝生长速率分别为1.02 cm/d和0.88 cm/d，在120 mg/kg时，总硒量最高达166.53 mg/kg，仍低于国标要求。诱变菌株和出发菌株的子实体生物学效率在硒浓度120 mg/kg时分别为92%和77%，两菌株的子实体农艺性状未发生变化。全基因组重测序分析表明，菌株120-5在基因组上发生了单核苷酸多态性(single nucleotide polymorphism,SNP)、插入或缺失(insertion-deletion,InDel)以及基因组结构变异(structure variation,SV)。【结论】菌株120-5在基因组信息上发生了有效突变，而且表现出强大的富硒能力，可以作为硒营养强化的目标菌株。

Abstract:

[Background] The cultivation of selenium-enriching edible fungi in their natural habitats often fails to meet the national standards for nutrient enrichment. [Objective] To screen out a selenium-enriching strain of Pleurotus ostreatus by ultraviolet mutagenesis, so as to provide a foundation for the product development with selenium-enriching edible fungi. [Methods] The strain to be mutated was determined by selenium resistance examination and then exposed to ultraviolet irradiation. The mycelial growth rate and the biological efficiency, total and organic selenium content of fruiting bodies were determined to evaluate the performance of the mutant strain. [Results] In the media with 100 mg/kg and 120 mg/kg selenium, respectively, the strain 120-5 showed the mycelial growth rates of 1.27 cm/d and 1.19 cm/d and the total selenium content of 199.77 mg/kg and 224.15 mg/kg in the fruiting bodies of 120-5. The organic selenium content in the fruiting bodies in the two treatments reached 198.83 mg/kg and 223.56 mg/kg, accounting for 99.53% and 99.74% of the total selenium, respectively. These values met the national standards for nutrient enrichment. However, in the media with 100 mg/kg and 120 mg/kg selenium, the original strain qiu-2020 showed the mycelial growth rates of 1.02 cm/d and 0.88 cm/d, respectively. It is noteworthy that in the medium with 120 mg/kg selenium, the original strain achieved the highest selenium content of 166.53 mg/kg, which fell short of the national standards. In the presence of 120 mg/kg selenium, the biological efficiency of the mutant strain and the original strain reached 92% and 77%, respectively. Remarkably, the agronomic traits of both the mutant and original strains remained unaltered. The whole-genome resequencing results unveiled single nucleotide polymorphism (SNP), insertion-deletion (Indel), and structure variation (SV) between the mutant and original strains. [Conclusion] The strain 120-5 with significant genomic mutations showcased a robust capacity of selenium enrichment, serving as a compelling candidate for nutrient enrichment.