烟草转录因子NtNAC080在非生物胁迫下的表达分析及功能鉴定

Expression and functional characterization of NtNAC080 transcription factor gene from Nicotiana tabacumin under abiotic stress

NAC作为植物特有的转录因子,广泛参与植物生长发育、衰老及胁迫响应等生物学过程。为探究烟草NtNAC080在非生物胁迫响应中的功能,利用qRT-PCR技术分析了不同胁迫处理下NtNAC080的表达模式,结果表明,NtNAC080的表达受干旱、高盐胁迫以及ABA、MeJA和SA激素的诱导;以NtNAC080基因的敲除突变体及野生型(K326)烟株为材料,分析敲除株系在高盐和干旱胁迫下抗逆表型。试验表明,与野生型相比,2个敲除株系的耐盐抗旱能力均明显增强;干旱和盐胁迫下敲除株系的抗氧化酶(SOD、POD、CAT)活性以及可溶性蛋白、脯氨酸含量显著高于野生型,而丙二醛含量显著低于野生型。相反地,异源表达NtNAC080的转基因拟南芥与野生型(Col-0)相比对盐和干旱的耐受性明显减弱。qRT-PCR分析发现在干旱和盐处理后胁迫相关基因(NtDREB1A、NtKAT2、NtNHX1等)在NtNAC080基因敲除株系中表达水平显著高于野生型。以上结果表明,NtNAC080在烟草的非生物胁迫响应中起负调控作用,这可能是通过调控抗氧化酶活性及胁迫相关基因的表达来实现的。

NAC proteins,which constitute one of the largest plant-specific transcription factor families,are widely involved in the regulation of plant development,senescence and stress responses.To explore the function of NtNAC080 in abiotic stress response,qRT-PCR was used to analyze the relative expression pattern of NtNAC080 genes under different abiotic stress treatments.Results showed that the relative expression level of NtNAC080 genes was induced by drought,salt,ABA,MeJA,and SA treatments.The NtNAC080 mutant and WT(K326)plants were used to analyze the phenotypes under salt and drought stresses.Results showed that NtNAC080 knockout tobacco lines had increased tolerance to salt and drought stresses.Under salt and drought stresses treatments,the antioxidant enzymes(SOD,POD,and CAT)activities,soluble protein,and proline contents of these two knockout lines plants were significantly higher than those of WT,while MDA content was significantly lower than that of WT.In contrast,NtNAC080-overexpressing Arabidopsis plants had more sensitive to salt and drought stresses.Furthermore,NtNAC080 mutation in tobacco resulted in the up-regulated expression of abiotic stress-related genes(NtDREB1A,NtKAT2,and NtNHX1)after salt and drought treatments.These results indicated that NtNAC080 could be play a negative role in response to salt and drought stresses by regulating the activity of antioxidant enzymes and the relative expression level of stress-related genes.