文心兰PLC基因家族鉴定及其应答软腐菌侵染转录模式

Identification of the PLC gene family of Oncidium hybridum and transcriptional patterns in response to soft rot infection

磷酸肌醇信号途径广泛参与生物体内多种细胞信号转导过程,PLC是该信号途径中的关键酶,在植物先天性免疫反应中起核心作用.为鉴定文心兰PLC基因家族成员、了解成员特征及其在应答软腐病菌侵染过程中的表达模式,基于‘南茜’文心兰应答软腐病菌侵染的转录组数据,利用生物信息学方法对其蛋白理化性质、亚细胞定位、二级结构、系统进化特征、保守氨基酸序列、蛋白互作网络及在文心兰感病过程中的表达模式(RPKM值)进行分析.共鉴定得到9个文心兰PLC基因家族成员,其编码蛋白的长度在332-600 aa,分子量(Mr)约为36.92×10^(3)-68.44×10^(3),等电点介于5.42-8.50,均属于不稳定亲水蛋白.亚细胞定位预测结果表明,文心兰PLC蛋白在过氧化物酶体、细胞核、细胞质、叶绿体和线粒体中均有分布.根据进化树和保守基序分析,文心兰PLC蛋白可分为PI-PLC和NPC 2个亚族,包含18个保守基序.String构建蛋白互作网络发现,PLC家族成员可能与PTEN3、PIP5K、PIS1以及G蛋白存在互作关系.RNA-seq表达量分析表明,9个文心兰PLC家族基因在‘南茜’文心兰不同感病时期(12 h和36 h)有明显不同的表达规律.其中,OhNPC1、OhPLC3以及OhPLC5在病原菌侵染初期与后期均显著上调表达,OhPLC4和OhPLC6在病原菌侵染后期显著上调表达.本研究表明OhNPC1、OhPLC3、OhPLC4、OhPLC5和OhPLC6可能在文心兰抵御软腐菌侵染过程中发挥重要作用.(图8表5参50)

Phospholipid signaling has been found to play a significant role in regulating various cellular processes,including plant growth and development,as well as in response to stress.Phospholipase C(PLC)is one of the major components of the phospholipid signaling network,and is involved in the plant’s innate immunity.Here,we sought to identify the genes in the PLC family of Oncidium hybridum and investigate the characteristics of PLC members and their expression patterns at different time points after infection with a soft rot pathogen.Bioinformatics approaches were used to identify genes in the PLC family based on the transcriptome data of O.hybridum‘Gower Ramsey’,at three different time points 0,12,and 36 h post-inoculation(HPI)with the soft rot pathogen.Additionally,protein physical and chemical properties,subcellular localization,secondary structure,phylogeny,protein conserved domains,interacting proteins,and the expression pattern of the OhPLC members were analyzed.The results showed that nine OhPLC genes were identified,which encoded proteins that were 332 to 600 amino acids in length,with predicted molecular weights(Mr)varying from 36.92×10^(3)to 68.44×10^(3)and theoretical isoelectric points ranging from 5.42 to 8.50.All of these were predicted to be unstable hydrophilic proteins that were localized in the peroxisome,nucleus,cytoplasm,chloroplast,and mitochondria.According to the phylogenetic tree and motif analysis,there are 18 conserved motifs of OhPLCs,the OhPLCs gene family can be divided into phosphoinositide-specific PLCs(PI-PLCs)and non-specific PLCs(NPCs)subfamilies,which have six and three members,respectively.Moreover,protein interaction analysis revealed that PLC family members might interact with PTEN3,PIP5K,PIS1,and G proteins.Transcript profiling showed that three genes(OhNPC1,OhPLC3,OhPLC5)were upregulated during different stages of pathogen infection,and two genes(OhPLC4 and OhPLC6)showed a higher expression pattern at 48 HPI.These findings suggest an important role for different OhPLC members in the response to soft rot infection,and provide a reference for elucidating the biological functions of OhPLCs.