College of Resources and Environmental Sciences, Nanjing Agricultural University, No.1 Weigang, Xiaolingwei Street, Xuanwu District, Nanjing, Jiangsu 210095, China.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, No.1 Weigang, Xiaolingwei Street, Xuanwu District, Nanjing, Jiangsu 210095, China.
J Appl Microbiol. 2024 Sep 2;135(9). doi: 10.1093/jambio/lxae241.
Rhodotorula mucilaginosa (Rho) can develop a range of strategies to resist the toxicity of heavy metals. This study aimed to investigate the physiological responses and transcriptomic regulation of the fungus under different heavy metal stresses.
This study applied transmission electron microscopy and RNA-seq to investigate the fungal resistance to Pb, Cd, and Cu stresses. Under Pb stress, the activated autophagy-related genes, vesicle-fusing ATPase, and vacuolar ATP synthase improved vacuolar sequestration. This offsets the loss of lipids. However, the metal sequestration by vacuoles was not improved under Cd stress. Vacuolar fusion was also inhibited following the interference of intravacuolar Ca2+ due to their similar ionic radii. Cu2+ showed the maximum toxic effects due to its lowest cellular sorption (as low as 7%) with respect to Pb2+ and Cd2+, although the efflux pumps and divalent metal ion transporters partially contributed to the detoxification.
Divalent cation transporters and vacuolar sequestration are the critical strategies for Rho to resist Pb stress. Superoxide dismutase (SOD) is the main strategy for Cd resistance in Rho. The intracellular Cu level was decreased by efflux pump and divalent metal ion transporters.
红酵母（Rhodotorula mucilaginosa）可以发展出一系列策略来抵抗重金属的毒性。本研究旨在探讨真菌在不同重金属胁迫下的生理反应和转录组调控。
本研究采用透射电子显微镜和 RNA-seq 技术研究了真菌对 Pb、Cd 和 Cu 胁迫的抗性。在 Pb 胁迫下，激活的自噬相关基因、囊泡融合 ATP 酶和液泡 ATP 合成酶提高了液泡的螯合作用，从而弥补了脂质的损失。然而，在 Cd 胁迫下，液泡的金属螯合作用并没有得到改善。由于它们的离子半径相似，液泡融合也受到了液泡内 Ca2+的干扰而受到抑制。与 Pb2+和 Cd2+相比，Cu2+的细胞吸附率最低（低至 7%），因此表现出最大的毒性效应，尽管外排泵和二价金属离子转运蛋白部分有助于解毒。
二价阳离子转运蛋白和液泡螯合是 Rho 抵抗 Pb 胁迫的关键策略。超氧化物歧化酶（SOD）是 Rho 抵抗 Cd 胁迫的主要策略。通过外排泵和二价金属离子转运蛋白降低了细胞内 Cu 水平。
