长日照下IQM3在CO的下游调控拟南芥主根长度

IQM3 Regulated Main Root Length of Arabidopsis thaliana at Downstream of CO under Long Sunshine

摘要:

拟南芥(Arabidopsis thaliana)中IQM家族是含有IQ基序的钙调素结合蛋白家族，IQM3突变能增加主根长度，CO (CONSTANS)是光周期成花调控途径的重要成员，CO突变可缩短主根长度。该研究构建二者的双突变体研究IQM3与CO基因的遗传学关系。结果表明，新CO突变体co-12序列的第1个外显子上缺失了9个碱基ACTTGCTAG，其中含有限制性核酸内切酶BfaI的酶切位点CTAG。建立了可鉴定该突变体的分子标记：利用BfaI酶切跨编码区PCR产物时，野生型Col因有3个位点而得到4个片段，co-12因只有2个位点而得3个片段，CO/co-12杂合子得5个片段。在长日照下，co-12的主根长度比野生型Col短，iqm3-2的比野生型Col长，而双突变体co-12 iqm3-2的主根长度表型偏向于iqm3-2。因此，在长日照下，IQM3在CO的下游参与调控拟南芥主根长度。

Abstract:

In Arabidopsis thaliana, IQM family is a calmodulin-binding protein family containing IQ motifs, IQM3 mutation can increase main root length, CO (CONSTANS) is an important member of photoperiodic floral regulation pathway, CO mutation can shorten taproot length. The genetic relationship between IQM3 and CO gene was studied by constructing double mutants of IQM3 and CO. The results showed that the first exon in co-12 sequence of the new CO mutant was missing 9 base ACTTGCTAG, which contains the restriction endonucrenase BfaI restriction site CTAG. A molecular marker was established to identify the mutant. When the cross-coding PCR product was cleaved by BfaI enzyme, four fragments were obtained from wild-type Col because it had three sites, three fragments were obtained from co-12 because it had only two sites, and five fragments were obtained from CO/co-12 heterozygote. Under long sunshine, the main root length of co-12 was shorter than that of wild type Col, and that of iqm3-2 was longer than that of wild type, while the phenotype of double mutant co-12 iqm3-2 was more favorable to iqm3-2. Therefore, IQM3 acts downstream of CO to regulate main root length under long day in Arabidopsis.