AGAMOUS (AG), a member of MADS-box gene family, is a key gene related to regulation of flower development in plants. The AG homologous gene GBM5 (Accession No.: AY114304.1) was obtained from the transcriptome of Ginkgo biloba . Primers were designed according to the obtained GBM5 gene sequence, and the full-length cDNA sequence of GBM5 gene with 732 bp in size and 243 amino acids in coding product can be synthetized by designing primers. The comparative analysis of evolutionary tree and amino acid sequence showed that ginkgo GBM5 was closely related to cycads AG and black spruce AG . qPCR analysis showed that the expression of GBM5 in different tissues of Ginkgo biloba was different at different periods, the expression levels of different tissues are as follows: Female flower>Male flower>Primordia>Foliage; Its expression is high in the undifferentiated stage of flower bud, the expression patterns were: April leaf>May leaf>September leaf, April primordia>May primordia>September primordia.

AGAMOUS(AG)属于MADS-box基因家族成员,是与花发育调控相关的关键基因.从银杏转录组中得到AG类同源基因GBM5(登录号:AY114304.1),根据GBM5基因序列设计引物,克隆获得GBM5基因的全长cDNA序列,其大小为732 bp,编码产物含243个氨基酸.进化树及氨基酸序列比对分析表明银杏GBM5与苏铁AG、黑云杉AG亲缘关系较近.qPCR分析显示,GBM5在银杏不同组织和不同时期的表达量均有差异,不同组表达量为:雌花＞雄花＞茎端＞叶;其在不同时期叶片和茎端表达量均为:4月＞5月＞9月.

Ginkgo biloba is a dioecious plant with a long juvenile stage. With advances in molecular technology, expression verification and functional analysis of some MADS-box family genes have been performed to explore the flowering mechanism in Ginkgo. Here, we selected the gene Gb01884 of different expression from transcriptome sequencing database, and isolated it from the shoot apical meristem (STM) of Ginkgo biloba. Full-length cDNA was cloned and sequence alignment was performed by NCBI platform. The result showed that Gb01884 was designated as an allele gene and named as GbMADS6, a SOC1 homolog gene. Using RT-qPCR to explore the GbMADS6 expression in spatial dynamic, we found that its expression level was high in leaves, apex stems, short shoots of both male and female Ginkgo trees. Then, the expression level of GbMADS6 was measured at the different development stages of leaves and apex stems. In apex stems, the expression level of GbMADS6 increased at initial differentiation stage of flower bud, and decreased gradually along with flower bud development. In leaves, the expression level of GbMADS6 decreased at initial differentiation stage of flower bud, while increased at exuberant stage of flower bud differentiation. This study provides the basis for further understanding the regulation mechanism of flowering in Ginkgo.

Ginkgolic acid is an anacardic acid specifically distributes in the seeds, leaves and episperms of Ginkgo biloba L. Ginkgolic acid possesses multiple biological functions on disease resistance and pesticide. Ginkgolic acid is enriched in the episperm of G. biloba, which is usually disposed as garbage. Although enriched, the content of ginkgolic acid in episperm is still low, and the extraction process is tedious and costly, which limits its application. In this study, we systematically observed the development process of G. biloba episperm, and detected the variation of endogenous hormone and ginkgolic acid levels therein. The results indicated that auxin, cytokinin and gibberellin (GA1 and GA3) content dramatically varied during the whole development process, indicating their regulation roles in episperm development. Remarkably, the salicylic acid (SA) content showed a significantly positive correlation with ginkgolic acid content. Based on these findings, we implemented exogenous hormone treatment with an optimized combination (300 mg/L NAA + 100 mg/L 6-BA + 200 mg/L SA) on the developing fruits of G. biloba, which resulted in a 53.92% increase of episperm yield and a 21.63% increase of ginkgolic acid content. Our study not only clarified the key development events of G. biloba episperm, the ginkgolic acid content profile, and their relationship, but also provides a cheap and easy way to improve ginkgolic acid accumulation in G. biloba seeds.

SBP转录因子在植物生长发育、信号转导、胁迫应答等方面起着重要的调控作用,由SBP基因家族基因编码.为探究银杏SBP基因家族的特征及表达模式,采用高通量测序技术对银杏的叶、花芽和胚珠进行转录组测序,鉴定SBP基因家族成员,并进行基因定位、miRNA 156靶位点预测、进化关系以及表达模式的分析.本研究共鉴定到15个银杏SBP基因家族成员,该基因家族在染色体上分布较分散,编码产物长度差异较大,其中有5个成员具有miRNA156靶位点.蛋白保守基序分析显示,除GbSBP5、GbSBP12、GbSBP14不具有完整的SBP保守结构域外,其余成员编码蛋白均具有SBP保守结构域(包括2个锌指结构和1个核定位信号).聚类分析表明,银杏SBP基因家族成员可以分为8个亚组.表达分析显示,SBP基因家族成员在银杏叶、花芽、胚珠中的表达水平存在一定差异,且在叶和花芽的不同发育时期呈现出不同的表达模式.本研究为银杏SBP基因家族的功能分析奠定了基础,并为银杏分子育种提供了一定的理论依据.