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

据报道，MEA、DME、MET 1、FIS 2、FWA、PHE、SSRP 1是拟南芥的基因组印记基因。这些印记基因的柑橘同源基因有CLF、SWN、DME、ROS、MET 1、FIS 2、FWA、FWA 2、PHEa、PHEb和SSRP。利用柑橘同源基因的特异性引物，对无核桔洲、有籽桔洲和大竹柚的基因组DNA和cDNA进行PCR扩增。对扩增产物进行测序。在9个基因组DNA和8个cDNA基因中检测到SNPs。为了研究基因组印记基因在喜州和大田杂交胚乳或胚中的表达，需要在喜州和大田印记基因之间有不同的纯合SNP序列。在FWA和PHEb中检测到这些SNP多态性。研究了FWA在大田×无籽Kishu的幼种子中的表达，只有无籽Kishu的FWA表达。这一结果表明，柑橘FWA基因可能是一个基因组印记基因。

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.