| 镉胁迫小海绵羊肚菌氧化损伤及其抗氧化防御 |
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| 引用本文： | 徐鸿雁,谢占玲,孟清,马德娟,孙灵芝.镉胁迫小海绵羊肚菌氧化损伤及其抗氧化防御[J].菌物学报,2022,41(4):668-679. |
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| 作者姓名： | 徐鸿雁 谢占玲 孟清 马德娟 孙灵芝 |
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| 作者单位： | 1 青海大学生态环境工程学院,青海 西宁 8100162 青海大学农林科学院,青海 西宁 810016 |
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| 基金项目： | 青海省科技计划国际合作专项(2021-HZ-802) |
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| 摘 要： | 羊肚菌Morchella是全球广泛分布的食药用真菌,重金属镉(Cd)在羊肚菌中的积累受到越来越多的关注。然而,羊肚菌镉积累的机理尚不清楚。本研究通过在0-5.0 mg/L Cd浓度环境中培养小海绵羊肚菌Morchella spongiola,测定Cd胁迫下其菌丝生长速率、丙二醛(MDA)、过氧化氢(H2O2)、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽(GSH)、抗坏血酸(ASA)及细胞Cd积累量等生理生化指标,旨在明晰小海绵羊肚菌响应Cd毒害的抗氧化防御响应机理。结果表明随着Cd浓度的增加,小海绵羊肚菌菌丝生长呈现出“升-降-升-降”的双峰响应变化,其中0.15、0.90和1.50 mg/L为菌丝生长Cd浓度关键拐点。Cd胁迫导致的氧化损伤与其初始浓度呈现正相关,胁迫3 d时MDA和H2O2含量显示出较大提升,5.0 mg/L处理组MDA和H2O2含量比对照组分别高出5.80倍和6.08倍。胁迫浓度、胁迫时间对抗氧化系统的影响各异,SOD、POD活性随浓度增大而逐渐升高,在1.5-5.0 mg/L浓度范围内,SOD和POD酶活性分别增加了1.96倍和2.15倍;CAT和GSH-Px酶活在0.15 mg/L时达到最大值,之后增加Cd浓度酶活性被抑制;GSH和ASA含量在Cd胁迫初期呈浓度依赖性增加,胁迫5 d后表现二者含量先升高后降低。此外,小海绵羊肚菌胞外Cd积累量随着外源Cd浓度的提高而增加,而胞内Cd含量在浓度为1.5-5.0 mg/L范围内无明显增加。本研究首次系统研究了小海绵羊肚菌响应Cd胁迫浓度、胁迫时间的动态趋势与内在变化规律,不仅为羊肚菌与重金属相互作用关系研究奠定基础,也为羊肚菌用于Cd污染废水生物修复提供了理论依据。
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| 关 键 词： | 小海绵羊肚菌 镉 浓度拐点 镉吸收 抗氧化酶 |
| 收稿时间： | 2021-08-26 |
Oxidative damage and antioxidant defenses of Morchella spongiola in response to Cd stress |
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| Authors: | XU Hongyan XIE Zhanling MENG Qing MA Dejuan SUN Lingzhi |
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| Affiliation: | 1 College of Eco-Environmental Engineering, Qinghai University, Xining 810016, Qinghai, China2 Academy of Agriculture and Forestry Science, Qinghai University, Xining 810016, Qinghai, China |
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| Abstract: | Morchella is a widely distributed edible and medicinal fungal genus all over the world. More and more attentions have been paid to the accumulation of cadmium in Morchella. However, the mechanism of cadmium accumulation is not clear. In this study, Morchella spongiola was cultured in 0-5.0 mg/L cadmium media, and the physiological and biochemical indexes such as mycelial growth rate, malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione (GSH), ascorbic acid (ASA) and cellular cadmium accumulation were measured in order to clarify the mechanism of antioxidant defense response of M. spongiola to Cd toxicity. With the increase of cadmium concentration, the mycelial growth of M. spongiola showed a bimodal response of “rising-descending-rising-descending”, in which 0.15, 0.90 and 1.50 mg/L were the key inflection points of cadmium concentration in mycelial growth. The oxidative damage caused by cadmium stress was positively correlated with cadmium initial concentration, and the content of MDA and H2O2 increased greatly after 3 d stress. The content of MDA and H2O2 in the 5.0 mg/L treatment group were 5.80 and 6.08 times higher than that in the control group, respectively. The effects of cadmium concentration and stress time on anti-oxidation system were different, and the activities of SOD and POD increased gradually with the increase of cadmium concentration. In the range of 1.5-5.0 mg/L cadmium concentration, the activities of SOD and POD increased by 1.96 times and 2.15 times, respectively. The activities of CAT and GSH-Px reached the maximum at cadmium concentration of 0.15 mg/L, and then the enzyme activity was inhibited with the increase of cadmium concentration. The content of GSH and ASA increased in a concentration-dependent manner at the initial stage of cadmium stress, and then decreased after 5 d cadmium stress. The extracellular cadmium accumulation increased with the increase of exogenous cadmium concentration, but the intracellular cadmium content did not increase significantly in the range of 1.5-5.0 mg/L. The dynamic trend and internal change law of M. spongiola in response to cadmium stress concentration and stress time were studied systematically for the first time, and this study laid a foundation for the further study of the interaction between Morchella and heavy metals, advantaging the application in bioremediation of cadmium-contaminated wastewater by using mycelia of Morchella. |
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| Keywords: | Morchella spongiola cadmium concentration inflection point cadmium absorption antioxidant enzymes |
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