草菇S-腺苷-L-高半胱氨酸水解酶同源基因Cor3低温条件下的表达变化

Expression of a Low Temperature-Induced S-Adenosyl-L-homocysteine Hydrolase Gene(Cor3) in a Low Temperature Sensitive Strain and a Cold Tolerant Mutant of Volvariella volvacea

将草菇(Volvariella volvacea)菌株V23和耐低温诱变菌株VH3的菌丝体在4℃下处理不同时间后,采用荧光定量PCR技术中的双标准曲线法研究了S-腺苷-L-高半胱氨酸水解酶同源基因Cor3的表达变化。结果显示,低温处理后,草菇V23菌株的Cor3基因表达量随处理时间的延长呈不断下降趋势,10h时,其表达量仅为对照的7%。而VH3菌株Cor3基因4℃处理2h表达量明显上升,为对照的1.8倍,处理4h和6h表达量降低,分别为对照的80%和90%,处理8h的表达量又上升,为对照的1.4倍,随后下降,处理10h表达量最低,为对照的60%。根据结果初步推测Cor3基因与草菇低温耐受性具有一定相关性。

The high temperatures necessary for vegetative growth and fruiting of the edible mushroom,Volvariella volvacea,restrict industrial scale cultivation to tropical and sub-tropical regions,thereby limiting the wider industrial exploitation of this important edible species. As part of a study aimed at developing commercially viable,cold-tolerant strains of V. volvacea capable of growing and fruiting in temperate climes,we have used real-time quantitative PCR to compare expression levels of a gene encoding for S-adenosyl-L-homocysteine hydrolase （Cor3） in two strains of V. volvacea,a low-temperature sensitive strain （V23） requiring temperatures 28 ℃ for normal vegetative growth and fruiting,and a cold-tolerant mutant （VH3）,following exposure to 4 ℃. Relative expression levels of Cor3 in parental V23 mycelia exhibited a general decrease with time following exposure,declining by 80% and ~30% of initial values after 2 h and 4 h,respectively. After 10 h,the transcription level was only 7% of that prior to low temperature exposure. Conversely,relative Cor3 expression levels in mutant VH3 mycelia exposed to 4 ℃ were proportionately higher throughout the treatment period. Expression levels after 2 h were ~1.8-fold higher than initial levels,and then fluctuated between ~80%-90% of zero time levels after 4~6 h. Gene transcription again increased （to ~140% of zero time levels） after 8 h,and then fell to ~60% of initial levels after 10 h exposure. Our data indicate that low levels of Cor3 expression are linked to the low temperature sensitivity of V. volvacea mycelium.