CWI和HOG信号通路基因在斑玉蕈不同发育阶段的表达模式

The expression pattern of CWI and HOG signal pathway genes during the growth and development of Hypsizygus marmoreus

为了更清楚地了解MAPK信号通路中的细胞壁完整性信号通路(cell wall integrity,CWI)和高渗透压甘油(high-osmolarity glycerol pathway,HOG)信号通路对斑玉蕈菌丝成熟、原基形成和子实体发育过程的影响及调节作用,对MAPK信号通路中的CWI和HOG信号通路基因在斑玉蕈不同菌丝培养时间(40、60、80和100d)和不同生长发育关键时期(24h、菌丝恢复期、菌丝转色期、原基期和子实体期)的表达模式进行分析,以期揭示这两条信号通路基因参与调节斑玉蕈菌丝的生长、子实体的形成和发育的作用。在斑玉蕈的CWI和HOG信号通路中经分析鉴定一共获得了15个关键基因。CWI信号通路基因表达分析表明:在菌丝培养的40-100d的过程中,大部分CWI信号通路基因在第60天时表达量最高,其中rho1、ssk1、ssk2和ste20的基因表达量上调了2-5倍,在第80-100天时出现持续下降。在HOG信号通路中的大部分基因也在菌丝培养的第60天表达量达到最高。其中sho1、ste20、ssk1和ssk2基因的表达量上调最为显著,而hog1基因的表达量在菌丝培养的第40-100天呈持续下降。子实体形成过程中两条通路的大部分基因在原基形成时期表达量最高,而在子实体时期表达量下调。其中HOG信号通路中的ssk2基因表达量上调最为显著。以上结果说明在菌丝生长过程中第60天时菌丝细胞生长增殖最为旺盛,而在第80天开始菌丝细胞基本开始停止生长,菌丝也逐渐达到成熟。同时在菌丝增殖生长过程中,斑玉蕈持续地上调CWI信号通路基因的表达来调控菌丝细胞壁的完整性,从而控制菌丝细胞壁的形成。其中bck1、mkk1和slt2基因可能对斑玉蕈菌丝细胞的分裂增殖和细胞壁的形成以及诱导子实体形成起到关键作用。

The influence and regulation of the cell wall integrity(CWI) signal pathway and high-osmolarity glycerol(HOG) signal pathway on the mycelial maturation, primordial formation and fruiting body development were investigated. The genes expression patterns of the CWI and HOG signal pathways were analyzed at different mycelial culture duration(40 d, 60 d, 80 d and 100 d) and different developmental stages(24 h after scratch, mycelial regeneration, mycelial pigmentation, primordium formation, and fruitification) and the functions of the two signaling pathway genes in regulating growth and development of Hypzisygus marmoreus were revealed. A total of 15 key genes was obtained in the CWI and HOG signaling pathways. The results showed that most of the CWI signaling pathway genes had the highest expression level at day 60 in culture period of 40–100 d, and the expression levels of rho1, ssk1, ssk2 and ste20 were up-regulated 2–5 times, but the expression levels continuously declined in period of 80–100 d. Most of the genes in the HOG signaling pathway also showed the highest expression levels on day 60. Among them, the expression levels of sho1, ste20, ssk1 and ssk2 were up-regulated most significantly, while the expression levels of hog1 showed a continuous decline during the period of 40–100 d. During the fruiting body developmental process, most of the genes in the two pathways had the highest expression levels at the primordium formation stage, and were down-regulated at fruiting stage. Among them, the expression of ssk2 gene in the HOG signaling pathway was up-regulated most significantly. These results indicated that the hyphal cell proliferation was most vigorous at day 60 during mycelial growth process, and began stable at day 80, and then the mycelia were gradually maturity. At the same time, the integrity of the mycelial cell wall was regulated by CWI signaling pathway genes in the process of mycelial proliferation, thereby controlling the formation of the mycelial cell wall. The genes bck1, mkk1 and slt2 might play a key role in the division and proliferation of mycelial cells and the formation of cell walls and thereby induced the formation of fruit bodies.