低温胁迫对人参皂苷生物合成途径基因家族表达特性的影响研究

Effect of cold stress on expression characteristic of gene families of ginsenoside biosynthesis pathway

目的研究低温胁迫对人参皂苷生物合成途径的3个基因家族3-羟基-3-甲基戊二酰CoA还原酶(PgHMGR)、鲨烯合酶(PgSS)、鲨烯环氧酶(PgSE)的影响,探讨各个家族成员响应低温的机制,并推测出响应低温的关键家族基因。方法将3周大的新鲜人参愈伤组织放置在5℃的冰箱中,分别在0、0.5、1、2、3 d后进行取样,分别记作CK、D1、D2、D3、D4,进行RNA提取和反转录实验,实时荧光定量PCR检测低温胁迫处理下不同基因的表达量。结果 PgHMGR1的表达量在D3时期达到对照组的1.3倍,PgHMGR2的表达量在D1时期达到峰值,为对照组的3.8倍;PgSS1的表达量在D3时期达到对照组的1.7倍;PgSE1和PgSE2的表达量均在D1时期分别达到对照组的6.9倍和6倍。其他家族基因(PgHMGR3、PgSS2、PgSE3)的表达量均无显著性变化。结论人参皂苷生物合成途径各个基因家族积极响应低温胁迫处理,推测PgHMGR1、PgHMGR2、PgSS1、PgSE1和PgSE2是人参愈伤组织响应低温胁迫时的关键家族基因。

Objective To investigate the effect of cold stress on the three gene families（PgHMGR,PgSSs,and PgSEs） of the ginsenoside biosynthetic pathway,and to explore the mechanism of genes response to cold stress and find the key genes.Methods The cold stress treatment was performed by selecting 3 weeks fresh callus which placed in the 5 ℃ refrigerator,and harvested after 0,0.5,1,2,and 3 d treatment for further analysis,were recorded as CK,D1,D2,D3,and D4,respectively.Results The expression of PgHMGR1 reached 1.3times compared to the control group at D3 period,and the expression of PgHMGR2 reached the peak at D1 period,which was 3.8 times of the control group;the expression of PgSS1 was 1.7 times of the control group（D3 period）;and the expressions of PgSE2 and PgSE1 were 6.9 and6 times higher than those of the control group,respectively.There was no significant change of the expression of PgSS2,PgSE3,and PgHMGR3.Conclusion The gene families of ginsenoside biosynthesis pathway positively response to cold stress treatment,and PgHMGR1,PgHMGR2,PgSS1,PgSE1,and PgSE2 may be the key family genes when Panax ginseng callus response to cold stress.