大豆microRNA168调控植物低磷胁迫响应

摘要

MicrRNNs (miRNA) are noncoding RNA participating in regulation of many environmental clues.In this study,MIR168 encoding mature miR168 was cloned from soybean genome and ligated to plant expression vector.Tobacco transgenic lines with overexpressed MIR168 were obtained and used to test tolerance to phosphorus deficiency.The transgenic lines grew better than wild type under phosphorus deficiency with longer roots,heavier roots and shoots.The expression of miR168 was higher in transgenic lines than in wild type,and the expression of targeted gene AGO1 was higher or equivalent to transgenic lines compared to wild type,indicating that a reulated loop took place between miR168 and AGO1.Seed germination in tobacco transgenic lines with overexpressed MIR168 was inhibited by ABA or JA,suggesting that miR168 was involved in regulating ABA or JA signal pathway.The results could assist the application of soybean miR168 to regulate phosphorus deficiency in plant and breeding of phosphorus-efficient crops.%为研究miR168在大豆响应低磷胁迫中的调控作用,从大豆中克隆了编码大豆miR168的基因MIR168,连接到植物表达载体后转化烟草,获得超量表达阳性转基因株系后鉴定其对低磷胁迫的耐受性.研究结果表明,超量表达MIR168烟草在低磷胁迫时长势强于对照,根长较对照长,地上部和地下部鲜重也显著高于对照,表明MIR168能够提高烟草对低磷的耐受性.MIR168过量表达烟草中miR168表达高于对照,其推定的靶基因AGO1的表达高于或与对照相当,表明miR168和AGO1之间存在相互调控.进一步分析miR168参与的信号调控发现,超量表达MIR168的烟草种子萌发受ABA和JA抑制,对GA3不敏感,表明miR168可能参与了ABA和JA信号调控.本文研究结果将有助于应用大豆miR168调控植物低磷胁迫,为培育磷高效植物提供基因资源.