空心莲子草SOD基因家族鉴定和表达模式分析

Genome-wide identification and expression analysis of the SOD gene family in Alternanthera philoxeroides

超氧化物歧化酶(SOD)是一类保守的抗氧化酶,在植物生长发育和胁迫应答响应过程中发挥重要作用。目前,尚缺乏对空心莲子草SOD家族成员的系统认识。本研究通过生物信息学对空心莲子草SOD基因家族进行了系统的鉴定及分析,并对其理化性质、保守基序、基因结构、系统发育进化关系、miRNA靶向关系和表达模式等进行了分析。结果表明,在空心莲子草中共鉴定到43个ApSOD,其中22个属于Cu/ZnSOD亚家族,21个属于Fe/MnSOD亚家族;蛋白质特征分析表明,36个ApSOD蛋白为亲水蛋白,37个ApSOD蛋白为稳定蛋白;亚细胞定位预测发现,大部分Cu/ZnSOD定位在叶绿体或细胞质,大多数Fe/MnSOD定位在线粒体。保守结构域分析发现,同亚家族中的成员具有相似的保守基序与基因结构。miRNA靶向关系预测发现,17个空心莲子草miRNA通过切割或翻译抑制作用靶向14个ApSODs。表达模式分析发现,ApSODs在不同环境条件和组织中表达水平相对稳定。利用RT-qPCR分析了6个ApSODs在除草剂处理下的表达模式,结果表明,在噁草酮和氯氟吡氧乙酸胁迫下,6个ApSODs在药后7 d内显著上调表达;在乙羧氟草醚胁迫下,4个ApSODs随着处理时间的延长表达量呈先上升后下降再回升的趋势;在草甘膦胁迫下,6个ApSODs在7 d时显著上调表达;在异丙隆胁迫下,4个ApSODs在1 d时均显著下调表达。说明在除草剂胁迫下ApSODs表现出不同的表达模式。本研究对空心莲子草ApSOD家族成员进行系统鉴定和特征分析,并初步揭示了6个基因在除草剂胁迫下的表达特征,为进一步研究ApSODs在响应除草剂胁迫中的生物学功能奠定了基础。

Superoxide dismutase(SOD)is a conserved antioxidant enzyme,which plays an important role in plant growth and development and stress response.Currently,there is a lack of systematic understanding of the SOD gene family members of Alternanthera philoxeroides(Ap).This study systematically identified and analyzed the SOD gene family in A.philoxeroides using bioinformatics methods.The physicochemical properties,conserved motifs,gene structure,phylogenetic relationship,miRNA targeting relationship and expression pattern were analyzed.The results showed that a total of 43 ApSOD proteins were identified,of which 22 belonged to the Cu/ZnSOD subfamily and 21 belonged to the Fe/MnSOD subfamily.Protein characteristic analysis showed that 36 ApSOD proteins were hydrophilic proteins,and 37 ApSOD proteins were stable proteins;subcellular localization prediction showed that most Cu/ZnSOD proteins were localized in chloroplasts or the cytoplasm,and most Fe/MnSOD proteins were localized in mitochondria.Conserved domain analysis showed that members of the same subfamily had similar conserved motifs and gene structures.Prediction of miRNA targeting relationships showed that 17 miRNAs target to 14 ApSODs through cleavage or translation inhibition.Expression pattern analysis showed that the expression level of ApSODs were relatively stable in different environmental conditions and tissues.The expression patterns of 6 ApSODs were analyzed by RT-qPCR under herbicide treatment.Six ApSODs were significantly up-regulated within 7 d under oxadiazon and fluroxypyr stresses;under fluoroglycofen stress,the expression of four ApSODs initially increased and then decreased,and then increased again with extended duration of herbicide exposure.Under glyphosate stress,the expression of six ApSODs were significantly up-regulated at 7 d;the expression of four ApSODs were significantly down-regulated at 1 d under isoproturon stress.These results indicate that ApSODs showed different expression patterns under the stress of different herbicides.This study systematically identified and characterized the ApSOD family members and provided a preliminary description of the expression characteristics of six genes under herbicide stress,laying a foundation for further research on the biological role of ApSODs in response to herbicide stress.