白刺NtBES1转录因子家族的鉴定及分析

Identification and Expression Analysis of NtBES1 Transcription Factor Family in Nitraria tangutorum

该研究基于白刺(Nitraria tangutorum)全长转录组数据,以白刺幼苗为材料,利用生物信息学手段,从转录组数据中鉴定白刺NtBES1家族成员,预测其理化性质、磷酸化位点、亚细胞定位,分析其保守结构域和系统进化关系;采用荧光定量PCR方法分析该家族基因在不同浓度PEG和NaCl处理下白刺叶片中的表达模式,为深入研究白刺NtBES1家族成员的功能以及白刺抗逆分子机理奠定基础。结果表明:(1)从白刺全长转录组中共鉴定出7个具有完整BES1_N保守结构域的NtBES1成员,分别命名为NtBES1-1~NtBES1-7。(2)NtBES1蛋白氨基酸数在86~422 aa之间,分子量在9.75~47.53 kD之间,等电点在5.29~10.22之间,不稳定指数范围在34.88~75.02之间,平均亲水系数均为负值。(3)亚细胞定位预测结果显示,NtBES1-6定位在细胞质中,其余6个成员均被定位在细胞核中。(4)系统发育树将7个成员分为3组,NtBES1-2、NtBES1-3和NtBES1-7为一组,NtBES1-1、NtBES1-5和NtBES1-6为一组,NtBES1-4单独为一组,且同组成员的结构、理化性质以及功能注释均相似。(5)经预实验筛选的表达水平较高的3个基因在胁迫下呈现不同的表达模式,其中:NtBES 1-2和NtBES 1-6仅在30%PEG胁迫2 h时表达上调;NtBES 1-2和NtBES 1-4在200 mmol/L NaCl处理2 h时表达量最高,在450 mmol/L NaCl处理12 h后3个基因的表达陆续开始上调,于24 h时表达量达到最高。研究认为,白刺NtBES1家族成员结构特征存在差异,且不同成员在白刺耐干旱和耐盐的过程中发挥不同的作用。

The study was based on full-length transcriptome data from Nitraria tangutorum,and the seedlings of N.tangutorum were used as experimental materials,NtBES1 family members from the transcriptome were identified and bioinformatics analysis were carried out;in addition,quantitative Real-time PCR was applied to analysis the expression patterns of NtBES1s in leaves treated with different concentrations of PEG and NaCl,which lay the foundation for the in-depth study of function of NtBES1 family members and molecular mechanism of stress resistance in N.tangutorum.The results showed that:(1)a total of 7 NtBES1s with complete BES1_N conserved domains were identified,and they were named as NtBES1-1-NtBES1-7;(2)the amino acids number of NtBES1 protein ranged from 86 to 422 aa,the molecular weight ranged from 9.75 kD to 47.53 kD,the isoelectric point ranged from 5.29 to 10.22,the instability index ranged from 34.88 to 75.02,and the average hydrophilic coefficient was negative;(3)the prediction results of subcellular localization showed that NtBES1-6 was localized in the cytoplasm,and the remaining 6 members were localized in the nucleus;(4)the seven NtBES1s were divided into three groups by phylogenetic tree,NtBES1-2,NtBES1-3 and NtBES1-7 were a group,NtBES1-1,NtBES1-5 and NtBES1-6 were a group,and NtBES1-4 was a single group,and the structure,physicochemical properties and functional annotations of the members in same groups were similar;(5)the three genes with high expression levels screened in the pre-experiment showed different expression patterns under stress:NtBES 1-2 and NtBES 1-6 were upregulated only at 30%PEG treatment for 2 h;under NaCl treatment,NtBES 1-2 and NtBES 1-4 showed the highest expression at 200 mmol/L treatment for 2 h,after 450 mmol/L treatment for 12 h,the expression level of these three genes gradually began to up-regulate,and reached to their highest levels at 24 h.The research shows that there are differences in the structural characteristics of NtBES1s,and different members play different roles in drought and salt tolerance process.