The cold - resistance mechanism of a mutagenic Volvariella volvacea strain VH3 with outstanding traits revealed by transcriptome profiling

Background The straw mushroom (Volvariella volvacea) is one of the important vegetables that is popular for its delicious taste. However, the straw mushroom is sensitive to low temperature, resulting in economic loss during transportation and storage. We obtained a novel straw mushroom strain, named VH3, via ultraviolet mutagenesis. Results Our study revealed that VH3 exhibited high cold resistance compared to an ordinary straw mushroom cultivar, V23. We found that the electrolyte leakages of VH3 were always significantly lower than that of V23 treated with 4 °C for 0 h, 2 h,4 h, 8 h, 16 h, and 24 h. Before cold treatment (0 h), there were no difference of MDA contents, SOD activities, and CAT activities between VH3 and V23. At the late stage (8 h, 26 h, and 24 h) of cold treatment, the MDA contents of VH3 were lower while both the SOD and CAT activities were higher than those of V23. To investigate the potential mechanisms of VH3 cold resistance, we performed transcriptome sequencing to detect the transcriptome profiling of VH3 and V23 after 0 h and 4 h cold treatment. Transcriptome sequencing revealed that 111 differentially expressed genes (DEG) between V23 (0 h) and VH3 (0 h) (V23–0_vs_VH3–0), consisting 50 up-regulated and 61 down-regulated DEGs. A total of 117 DEGs were obtained between V23 (4 h) and VH3(4 h) (V23–4_vs_VH3–4), containing 94 up-regulated and 23 down-regulated DEGs. Among these DEGs, VVO_00021 and VVO_00017 were up-regulated while VVO_00003, VVO_00004, VVO_00010, and VVO_00030 were down-regulated in V23–0_vs_VH3–0 and VH3–4_vs_V23–4. KEGG and GO analysis revealed that the 6 DEGs were annotated to pathways related to cold stress. Besides, the GA3 content was also decreased in VH3. Conclusions Collectively, our study first revealed that the increased cold resistance of VH3 might be caused by the expression change of VVO_00003, VVO_00004, VVO_00017, VVO_00021, and VVO_00030, and decreased GA3.