低温驯化对绵头雪莲呼吸代谢及相关基因表达的影响

Effect of Low Temperature Acclimation on Respiratory Metabolism and Related Gene Expression of Tibet S.laniceps Hand.-Mazz.

为了研究高山植物对低温驯化的生理及分子适应机制。本研究以西藏绵头雪莲愈伤组织为材料,检测4℃低温驯化0、6、9 d过程中呼吸速率变化,并基于转录组数据库分析低温驯化对呼吸相关基因表达的影响。结果显示,低温驯化(4℃)初期使绵头雪莲愈伤组织呼吸速率和糖酵解速率降低,但随着驯化时间延长至第9天,呼吸速率及糖酵解有所回升;在愈伤组织呼吸测定系统中加入代谢抑制剂(叠氮化钠和水杨基氧肟酸)发现,常温培养、4℃低温驯化6 d及9 d的雪莲愈伤组织细胞色素C途径占总呼吸比例分别为86.21%、82.11%和80.40%;而交替呼吸途径占总呼吸比例由13.79%升高到17.89%和19.60%;同时抗氰呼吸途径的关键酶交替氧化酶(AOX)家族中AOX1、AOX2表达量升高。此外,低温驯化使糖酵解途径相关的己糖激酶(HK)基因家族成员表达量升高,磷酸果糖激酶(PFK)基因家族成员中3个成员表达量也在低温驯化后发生了不同程度的升高;磷酸戊糖途径关键酶葡萄糖酸内酯酶(PGLS)和6-磷酸葡萄糖酸脱氢酶(PGD)基因部分家族成员表达量在低温驯化后显著提高。结果表明低温驯化使高山植物绵头雪莲发生了一系列适应性变化,随着低温驯化时间延长,呼吸速率和糖酵解速率经历了由降低到升高的过程,同时抗氰呼吸途径加强,与糖代谢相关的关键酶基因表达量提高,为其应对高山地区恶劣的环境条件提供了重要的能量基础。

To study the physiological and molecular adaptation mechanism of the alpine plant Saussurea laniceps to low temperature.Changes of respiratory rate and the expression of genes related to respiration responded to cold acclimation(4℃,for 0,6,9 d,respectively)in S.laniceps callus were determinated.Results showed that callu respiration rate and glycolysis rate decreased after cold acclimation(4℃),but increased under 9-day cold acclimation.By adding inhibitors NaN3 and SHAMto the respiration measurement system,the proportions of cytochrome C pathway in total respiration in callus cultured at room temperature and acclimated at 4℃for 6 days and 9 days were 86.21%,82.11%and 80.40%,respectively;while the proportion of alternative respiration pathway in total respiration increased from 13.79%to 17.89%and 19.60%,respectively.At the same time,the expressions of AOX1 and AOX2 were increased in the AOX family,the key enzymes of cyanide-resistant respiratory pathway.In addition,low temperature acclimation increased the expression of hexokinase(HK)family members related to glycolysis pathway,three members of phosphate fructose kinase(PFK)gene family also increased to varying degrees after low temperature acclimation,and the expression of some members of gluconate lactamase(PGLS)and 6-phosphate gluconate dehydrogenase(PGD)genes,the key enzymes of phosphate pentose pathway,increased significantly after low temperature acclimation.Cold acclimation caused adaptive changes in alpine plant S.laniceps.With the prolongation of cold acclimation,the respiration rate and glycolysis rate changed in a process from decreasing to increasing,while the cyanide-resistant respiratory pathway strengthened.The increased expression of key enzymes related to glucose metabolism provides an important energy basis for dealing with harsh environmental conditions in alpine plant S.laniceps.