玉米ZmNAOD基因的克隆与功能分析

Cloning and Function Analysis of ZmNAOD Gene in Maize

玉米籽粒发育和光周期特性是影响产量的关键因素。本文通过RT-PCR方法,从玉米骨干自交系昌7-2籽粒的cDNA中克隆得到一个乙酰鸟氨酸脱酰酶基因,命名为ZmNAOD。ZmNAOD的CDS (coding DNA sequence)长1344bp,编码447个氨基酸。qRT-PCR分析表明, ZmNAOD基因在玉米雄穗中的表达量最高,其次是在籽粒、叶、茎、根中;该基因在授粉后不同天数籽粒中的表达趋势为, 0~15 d快速上升,之后迅速下降。对该基因的过表达转基因拟南芥的研究表明,ZmNAOD基因在转基因拟南芥的根中表达量最高;经暗处理10d后,转基因株系根的长度显著长于野生型;转基因拟南芥的生育期明显提前,其粒长和千粒重显著大于野生型拟南芥。这些结果表明, ZmNAOD基因的表达可能与籽粒发育和光周期调控有关。

The development of kernels and the photoperiod characters are key elements that impact yield in maize.A N-acetylornithine deacctylase(NAOD)gene named ZmNAOD was cloned from maize inbred line Chang 7-2 by the method of RT-PCR in our work.The length of CDS(coding DNA sequence)in ZmNAOD gene is 1344 bp,coding a polypeptide of 447 amino acids.The expression of ZmNAOD was abundant in tassel,kernel,leaf,stem and root successively,and was up-regulated in seed from 0 to 15 d,and down-regulated after 15 d.The over-expression recombinant plasmid,pCAMBIA1304-ZmNAOD,was transformed into Arabidopsis using Agrobacterium mediated method,and homogeneous transgenic lines were obtained.The ZmNAOD gene expression was abundant in roots of transgenic Arabidopsis,and the root length was significantly longer than that of the wild type(WT)after a 10-day dark treatment.Flowering days of transgenic lines were earlier,the seeds were longer and the thousand seed weight was heavier than those of the WT.These results demonstrated that the ZmNAOD might be involved in seed development and photoperiod.