烟草转录因子NtMYC2对激素及非生物因素胁迫的响应

Response of tobacco transcription factor NtMYC2 to hormone and abiotic stress

为探究烟草转录因子NtMYC2对逆境胁迫的响应,以烟草幼苗为试验材料,用50μmol·L^-1 MeJA,100μmol·L^-1 ABA,200 mmol·L^-1 NaCl,20%PEG 6000,4℃和黑暗条件下分别进行激素诱导、高盐、模拟干旱、低温和暗胁迫处理,并取处理1,3,6,12,24和48 h时的烟草叶片提取RNA,反转录为cDNA后利用qRT-PCR技术分析NtMYC2的表达情况。结果表明,NtMYC2的表达受MeJA、ABA、干旱、高盐、低温和黑暗胁迫的诱导,且表达模式随激素和胁迫处理的不同而不同。NtMYC2的表达量随MeJA处理时间的延长呈先下降后上升的趋势,随ABA和黑暗处理时间的延长呈逐渐上升的趋势,都在48 h时达最高表达水平,但ABA诱导的表达水平最高,是对照的17.31倍。盐胁迫1 h时,NtMYC2的表达量是对照的3.95倍,随后下降,6 h后与对照相当。低温诱导NtMYC2表达上调,在处理6 h时表达量最高,48 h时最低(与对照无明显差异);模拟干旱胁迫48 h可显著提高NtMYC2的表达水平。此外,利用PlantCARE软件分析NtMYC2启动子区域,结果显示启动子区域包含有脱落酸、生长素、低温、干旱、光等多种非生物胁迫相关顺式作用元件。

To explore the response of tobacco NtMYC2 to adversity stress,tobacco seedlings were used as test materials.Under the conditions of 50μmol·L^-1 MeJA,100μmol·L^-1 ABA,200 mmol·L^-1NaCl,20%PEG 6000,4℃and darkness,the test materials were treated respectively with hormone induction,high salt,simulated drought,low temperature and dark stress.RNA was extracted from the tobacco leaves at 1,3,6,12,24 and 48 h after each treatment,and reverse transcription into cDNA was used to analyze the expression of NtMYC2 by qRT-PCR.The results showed that the expression of NtMYC2 was induced by MeJA,ABA,drought,high salt,low temperature and dark stress,and the expression pattern was different with the hormone and stress treatment.The expression level of NtMYC2 decreased first and then increased with the prolongation of MeJA treatment time,and increased gradually with the prolongation of ABA and dark treatment time,reaching the highest expression level at 48 h,but the expression level induced by ABA was the highest(17.31-fold that of the control).At 1h of salt stress,the expression of NtMYC2 was the highest(3.95-fold that of the control),then decreased,and was equivalent to that of the control at 6 h.The expression of NtMYC2 was up-regulated by low temperature,reaching the highest level at 6 h and the lowest at 48h(no significant difference with the control).Simulation of drought stress for 48 h could significantly improve the expression level of NtMYC2.In addition,PlantCARE software was used to analyze the NtMYC2 promoter region,and the results showed that the promoter region contained abscisic acid,auxin,low temperature,drought,light and other abiotic stress-related cis-acting elements.