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- Title
蛹虫草菌株退化特征及鉴别方法.
- Authors
怀美玉; 刘晴; 徐方旭; 王升厚; 董彩虹
- Abstract
Strain degeneration occurs often in Cordyceps militaris during subculture and long-term storage at low temperature, resulting in a decrease in yield and a great loss in income. In this study, normal strains and degenerated strains due to long-term storage at 4 °C PDA slant and continuous subculture of C. militaris were observed to survey the morphological variation of fruiting bodies, colonies and mycelia and sporulation capacity of conidia. The nuclei, mitochondria, reactive oxygen species accumulation in cell, and lipid droplets in blastospore were observed by staining method, and the content of cordycepin, adenosine and ergosterol in mycelia was analyzed. The results showed that most of the phenotypical variation of degenerated strains caused by long-term storage at 4 °C PDA slant and continuous subculture were consistently displayed as: the decrease of fruiting body yield, the presence of adhesive and knotted hyphae, significant decrease of conidia, increased level of reactive oxygen species, reduction of mitochondria in the mycelia, mergence of dispersed and small lipid droplets in the blastospores into large droplets. There is no color change after being exposed to light for the colony of degenerated strains caused by long-term storage at 4 °C, whereas color change is unstable during the continuous subculture. The number of nuclei in the mycelia of degenerate strains undergoing continuous subculture is reduced whereas no change in that undergoing long-term storage at 4 °C. The content of cordycepin, adenosine and ergosterol in the mycelia of degenerated strains of long-term preservation was reduced by 58%, 41% and 70% as compared with that of the normal strains, but the ergosterol content of the degenerated strains of continuous subculture was unchanging. Microscopic observation of adhesive and knotted mycelia, and staining the mycelia by nitrogen blue tetrazolium (NBT) to detect the reactive oxygen species are easy to operate and not time-consuming. This method can be used to detect the degeneration of C. militaris strains on a large scale. Mitochondrial and lipid droplet staining can also be used to identify the degenerated strains. The commonly used method of judging the quality of spawn by color conversion after light irradiation needs to be cautious. Obvious degeneration of the strains usually appears in fourth generation during subculture, so the strains used for cultivation should be selected within three generations.
- Subjects
REACTIVE oxygen species; FRUITING bodies (Fungi); FRUIT yield; LOW temperatures; SUBCULTURES
- Publication
Mycosystema, 2022, Vol 41, Issue 11, p1819
- ISSN
1672-6472
- Publication type
Article
- DOI
10.13346/j.mycosystema.220249