转基因枳橙中GA20ox1与rol ABC基因互作关系的研究

Study on Gene-gene Interactions between GA20ox1 and rol ABC Genes in Transgenic Citrange

以转rol基因枳橙实生苗为试验材料,研究其对赤霉素的敏感反应,用荧光定量RT-PCR分析GA20ox1基因和rol基因的表达,并检测幼芽中POD酶活性和植物内源激素含量的变化。结果表明转rol ABC基因枳橙既不属于GA缺陷型,也不属于GA不敏感型,幼芽中GAS、GAS(P【0.05)和IAA显著降低(P【0.01),POD酶活性显著提高(P【0.01)。转rol基因枳橙幼芽中GA20ox1基因mRNA水平相比对照显著下调(P【0.01)。在幼芽、嫩茎中,rol C基因与GA20ox1表达负相关。rol基因通过在幼芽中的高表达下调了GA20ox1基因转录表达,进而抑制了活性GAs在幼芽中的合成,顶端分生组织较低量的活性GAs限制植物茎伸长,在转rol ABC基因枳橙矮化性状建成中发挥重要作用。

The potted seedlings of transgenic citrange with rol ABC genes were used as trial materials, the sensitive response to gibberellins（GAs） was tested by spraying GA3 regularly.The expressions of GA20ox1 and rol A,B and C genes were detected by quantitative reverse transcription PCR and the phytohormone content of tender bud was quantified by GC/MS method.The results demonstrated that the transgenic citrange was neither defective genotype of GA3,nor unsensitive genotype of GA3.The contents of IAA（P<0.01）,GA1 and GA4 decreased（P<0.05） while the peroxidase activity increased markedly in the tender bud of transgenic citrange（P<0.01）.The GA20ox1 expression quantity markedly decreased in apical bud（P<0.01）.The expression of rol C gene and GA20ox1 gene reveal negative correlation in tender bud and tender stems.The rol genes’ expression could inhibit synthesis of GAs by down regulating the expression of GA20ox1 gene in bud and lower bioactive GAs could suppress citrange growth,then it played an important role in constructing dwarfing characteristics of transgenic citrange with rol ABC genes.