Is arrested embryo development of seedless Kishu mandarin related to genomic imprinting gene?

据报道，MEA、DME、MET1、FIS2、FWA、Phe、SSRP1是拟南芥中的基因组印记基因。这些柑橘基因组印记基因的同源基因分别为CLF、SWN、DME、ROS、MET1、FIS2、FWA、FWA2、PHEA、PHEB和SSRP。以无核基州蜜柑、多籽基州蜜柑和大七叶柚的基因组DNA和cDNA为模板，利用这些柑橘同源基因的特异引物进行了聚合酶链式反应。对扩增产物进行测序。在9个基因组DNA基因和8个cDNA基因中检测到SNPs。为了研究Kishu和Otachbana杂交的胚乳或胚胎中基因组印记基因的表达，Kishu和Otachbana印记基因之间的SNP纯合子序列是必要的。在FWA和PHEB中检测到了这些SNP多态。研究了FWA在OTACHACHANA×无核麒麟的幼粒中的表达，并且只表达了‘无核麒麟’FWA。这一结果表明，柑橘FWA可能是基因组印记基因。

It is reported that MEA, DME, MET1, FIS2, FWA, PHE, SSRP1 are genomic imprinting genes in Arabidopsis. Citrus homologue genes of these genomic imprinting genes were CLF, SWN, DME, ROS, MET1, FIS2, FWA, FWA2, PHEa, PHEb and SSRP. Genomic DNA and cDNA of Seedless Kishu, Seedy Kishu mandarin and Otachibana pummelo were used for PCR by specific primer of these citrus homologue genes. The amplified products were sequenced. The SNPs were detected in 9 genes of genomic DNA and 8 genes of cDNA. To investigate the genomic imprinting gene expressions in endosperm or embryo crossed by Kishu and Otachibana, different homozygous SNP sequence between Kishu and Otachibana imprinting gene is necessary. These SNP polymorphisms are detected in FWA and PHEb.The expression of FWA in young seeds resulted from Otachibana X Seedless Kishu was investigated, and only 'Seedless Kishu' FWA was expressed. This result indicated that citrus FWA would be genomic imprinting gene.