摘要：

在植物中,磷脂酰肌醇 4,5-二磷PIP5K基因家族中的PIP5K2基因在调控植物生长中起到了关键作用,为探明PIP5K2基因在蓖麻中的作用,以蓖麻PIP5K2基因为研究对象,对该基因进行基因克隆、生物信息学及表达分析。结果表明,以蓖麻cDNA为模板,通过PCR获得了长度为2 136 bp 的基因片段;通过对该基因编码的蛋白序列进行生物信息学分析,确定该PIP5K2基因编码的蛋白氨基酸的个数为 672,pI 值为 6.74,其分子质量为 76.47 ku,平均亲水性系数为-0.636,是一种亲水蛋白质,其二级结构包括α螺旋、β转角、延伸链、无规卷曲;由预测结果可知,PIP5K2蛋白的三级结构与二级结构是一致的且与麻风树同源性很高。PIP5K2 基因在单雌、标雌和两性系3种花序类型的五叶期时的相对表达量都普遍高,在主茎穗开花期相对表达量都普遍偏低;在标雌花序五叶期时有最高相对表达量,在两性花序的主茎穗开花期有最低相对表达量,最高相对表达量是最低相对表达量的 80 倍左右;在3种花序类型之间,PIP5K2基因在四叶期的相对表达量相似,但相较于单个花序类型植株的不同生长时期,PIP5K2基因在四叶期时的表达量要明显高于开花期。根据该结果推测,PIP5K2基因可能调控蓖麻植株中期的生长,与植株的矮化存在一定的相关性。

关键词: 蓖麻, PIP5K2基因, 生物信息学分析, 植物调控, 基因表达

Abstract:

In plants,the PIP5K2 gene of the phosphatidylinositol 4,5-bisphosphate PIP5K gene family plays a key role in regulating plant growth.To investigate the function of the PIP5K2 gene in castor gene cloning,bioinformatics analysis,and expression analysis of the castor PIP5K2 gene were conducted.The results showed that a gene fragment of 2 136 bp in length was obtained through PCR using castor cDNA as the template.Bioinformatics analysis of the protein sequence encoded by this gene determined that the PIP5K2 gene encoded a protein consisting of 672 amino acids,with a pI value of 6.74 and a molecular weight of 76.47 ku.The protein's average hydrophilicity was -0.636,classifying it as a hydrophilic protein.Its secondary structure included α-helices,β-turns,extended strands,and random coils.Based on the prediction results,the tertiary structure of the PIP5K2 protein was consistent with its secondary structure,and shared a high degree of homology with the Jatropha curcas.The relative expression levels of the PIP5K2 gene were generally high in the five-leaf stage of the female,marker female and bisexual inflorescence types,and were generally low in the main stem panicle flowering stage.The highest relative expression level was observed in the five-leaf stage of the marker female inflorescence,while the lowest relative expression level was observed in the main stem panicle flowering stage of the bisexual inflorescence.The highest relative expression level was approximately 80 times higher than the lowest relative expression level.Among the three inflorescence types,the relative expression level of the PIP5K2 gene was similar in the four-leaf stage.However,compared to different growth stages within each inflorescence type,the expression level of the PIP5K2 gene was significantly higher in the four-leaf stage than in the flowering stage.Based on these results,it can be inferred that the PIP5K2 gene may regulate the mid-stage growth of castor plants and have some correlation with plant dwarfing.

Key words: Castor, PIP5K2 gene, Bioinformatics analysis, Plant regulation, Expression