姬松茸菌株J1与J77镉富集差异及生理响应机制

以姬松茸菌株J_1及其诱变菌株J_(77)为材料,研究不同浓度镉对J_1、J_(77)菌丝生长与产量、镉富集量及相关氨基酸含量等的影响,分析J_1、J_(77)对镉吸收与耐受性差异及生理响应机制。结果表明:随着外源添加镉浓度的增加,J_1、J_(77)菌丝生长速度、产量均先增加后降低,低浓度镉能促进姬松茸生长、提高产量;相同浓度外源镉胁迫下,J_(77)菌丝及子实体中镉含量均低于J_1,且差异显著(P0.01),J_(77)为低富集镉的菌株;菌丝中镉含量与子实体中镉含量显著正相关(R20.97);J_1、J_(77)子实体中半胱氨酸含量均先降低后增加,低浓度镉胁迫下J_1半胱氨酸含量较高,高浓度镉胁迫下J_(77)中半胱氨酸含量较高,半胱氨酸可能与姬松茸镉富集密切相关。

Comparison and physiological mechanisms of cadmium (Cd) accumulation by strain J1 and mutant J77 of Agaricus brasiliensis

Agaricus brasiliensis is an edible and medicinal mushroom with a strong capability of cadmium accumulation, which may impact food security. Using a combination of 60Co-γ ray and UV light, we previously bred a new A . brasiliensis strain named J77 by irradiating mycelium of strain J1. Owing to its low Cd content and high stable yield, J77 was approved as a new variety named Fuji 77 by the Crop Variety Approval Committee of Fujian Province in 2013. Using the A . brasiliensis strain J1 and its mutant J77 as research materials, the effects of Cd in different concentrations on mycelium growth rate and yields, Cd accumulation and contents of three amino acids in mycelium, and fruiting bodies of J1 and J77 were analyzed by adding different concentrations of Cd into the culture medium to reveal the differences in Cd uptake, tolerance, and physiological response mechanisms between J1 and J77. The results showed that mycelium growth rate and yields of J1 and J77 increased first and then declined with the increase of Cd concentration, which indicated that Cd of lower concentrations could promote the growth of mycelium and increase the yields. Under the same concentration of Cd, Cd contents in both mycelium and fruiting body of J77 were significantly lower than those of J1, which indicated that J77 was a lower Cd accumulative strain. In addition, there was a significant positive correlation between Cd contents in mycelium and fruiting bodies(R2>0.97). Cysteine(Cys)contents in both fruiting bodies of J1 and J77 de-creased first and then increased with the increase of Cd concentrations. Cys content was significantly higher in fruiting body of J1 compared with J77 under lower Cd concentrations. In contrast, the Cys content in the fruit body of J77 was significantly higher than that of J1 under high-er Cd concentrations. These results indicated that Cys might play an important role in Cd accumulation in A . brasiliensis.