玉米ACO基因家族生物信息学及表达模式分析

Bioinformatics and Expression Pattern Analysis of Maize ACO Gene Family

【目的】对玉米1-氨基环丙烷-1-羧酸氧化酶ACO基因家族进行全基因组鉴定,分析其在玉米不同器官和不同发育时期以及响应外源激素和病菌侵染中的表达模式,为明确玉米ACO基因家族功能打下基础。【方法】利用生物信息学方法,在玉米B73自交系基因组中鉴定ACO,对其基因结构、蛋白质理化性质、家族成员间的亲缘关系以及保守基序进行分析,利用实时荧光定量PCR(real-time fluorescence quantitative PCR,qRT-PCR)技术分析ZmACO基因家族的表达模式。【结果】除ZmACO11外,ZmACO家族成员均具有Fe2+离子结合位点和底物抗坏血酸结合位点。系统发育分析显示,ZmACO_(2)与ScACO在同一分支,亲缘关系较近,Bootstrap值达98。基因表达分析表明,ZmACO_(2)、5、9、15、20、35在各发育时期均活跃表达,且在叶片中呈优势表达,因此选择上述6个基因进行下一步检测。喷施乙烯利后,上述6个基因的表达均有所波动,其中ZmACO_(2)的表达量受影响较大,变化幅度在8倍左右。在乙烯利处理的0—24 h内这6个基因的表达量存在波动,但在处理后24 h,6个基因的表达量均接近0。水杨酸处理后,ZmACO5的表达量受影响较大,变化倍数在2倍左右。其他基因的表达量在处理后24 h均接近0。ZmACO9、35在3—12 h的表达量存在波动,ZmACO_(2)、15、20表达量呈下调趋势。在响应生物胁迫方面,接种玉米大斑病菌(Setosphaeria turcica)后,ZmACO5、9的表达量变化幅度最大,在接种后第10天,这两个基因的表达量分别升至对照组的50和60倍。接种玉米小斑病菌(Cochlibolus heterostrophus)后,ZmACO5的表达量变化幅度较大,变化倍数在40—90倍。接种立枯丝核菌(Rhizoctonia solani)后,ZmACO5、35表达量变化幅度最大,在病菌接种的第3天达到200倍。【结论】ZmACO_(2)、5、20、35在玉米生长发育过程中表达变化最活跃;施加外源乙烯利和水杨酸可以对ZmACO的表达水平造成显著影响。病菌侵染玉米后ZmACO的表达水平产生显著变化,与生物胁迫应答关系密切。

【Objective】The objective of this study is to perform the genome-wide identification of the maize ACO(1-aminocyclopropane-1-carboxylate oxidase)gene family,analyze its expression patterns in different organs and developmental stages of maize,as well as in response to exogenous hormones and pathogen infection,and to lay the foundation for clarifying the function of the maize ACO gene family.【Method】Using bioinformatics methods,the ACO was identified in the genome of maize B73 inbred line,and its gene structure,protein physicochemical properties,phylogenetic relationships among family members,and conserved motifs were analyzed.The expression patterns of the ZmACO gene family were analyzed using real-time fluorescence quantitative PCR(qRT-PCR)technology.【Result】Except for ZmACO11,all members of the ZmACO family have Fe2+binding sites and substrate ascorbic acid binding sites.The phylogenetic tree showed that ZmACO_(2) and ScACO are in the same branch and have a close genetic relationship,with a Bootstrap value of 98.The gene expression analysis indicated that ZmACO_(2),5,9,15,20 and 35 were actively expressed at various developmental stages and exhibited dominant expression in leaves,so the six genes mentioned above were selected for the next step of testing.Spraying ethephon resulted in fluctuations in the expression of all six genes mentioned above,the expression level of ZmACO_(2) was significantly affected,with a variation multiple of about 8 times.The expression levels of these six genes fluctuated within 0-24 h of ethephon treatment.But after 24 h of treatment,all gene expression levels were close to 0.After salicylic acid treatment,the expression level of ZmACO5 was significantly affected,with a variation multiple of about 2 times.The expression levels of other genes were close to 0 at 24 h after treatment.The expression levels of ZmACO9,35 fluctuated between 3 to 12 h,and the expression levels of ZmACO_(2),15,20 showed a downward trend.In response to biological stress,the expression levels of ZmACO5,9 showed the greatest changes after inoculation with the Setosphaeria turcica,and on the 10th day after inoculation,the expression levels of these two genes increased by 50 and 60 times,respectively,compared to the control group.After inoculation with the Cochlibolus heterostrophus,the expression level of ZmACO5 changed significantly,with a variation multiple of 40-90 times.After inoculation with Rhizoctonia solani,the expression levels of ZmACO5,35 showed the greatest changes,reaching 200 times on the 3rd day of inoculation.【Conclusion】The expression changes of ZmACO_(2),5,20 and 35 are most active during the growth and development of maize;The application of exogenous ethephon and salicylic acid can significantly affect the expression level of ZmACO genes.The expression level of ZmACO genes significantly changes after bacterial infection in maize,which is closely related to the response to biological stress.