中文摘要：

以龙眼松散型胚性愈伤组织为材料．对miR398b前体进行克隆．并分析其在龙眼体胚发生过程中的表达。结果表明：获得长85bp的龙眼miR398b前体序列（GenBank登录号：GU968639），该前体与葡萄、毛果杨的miR398b前体序列具有较高的同源性，并包含长21bp的miR398b成熟序列；其在龙眼体胚发生过程中的表达具有组织特异性，主要在球形胚和子叶形胚阶段大量积累，在松散型胚性愈伤组织、胚性愈伤组织Ⅱ、不完全胚性紧实结构、心形胚和成熟胚阶段中等表达，在鱼雷形胚阶段几乎不表达，说明pre—miR398b主要在龙眼球形胚和子叶形胚阶段起主要作用．

英文摘要：

The miR398b precursor was cloned by RT-PCR and its expression level was analyzed using quantitative real-time RT-PCR for elucidating the role of miR398a during longan somatic embryogenesis. The miR398a precursor（GenBank locus GU968639）was 85 bp in length, including 21 bp mature sequence of miR398b, and showed high sequence homology with that from Vitis vinifera and Populus trichocozpa. The miR398a precursor showed strong expression in globular embryos and cotyledonary embryos, moderate expression in friable- embryogenic callus, embryogenic callus II, incomplete compact pro-embryogenic cultures, heart-shaped embryos and mature cotyledonary embryos, weak expression in torpedo-shaped embryos. The results indicated that longan miR398b precursor might play important roles in globulars and cotyledonary embryos.