目的 以蒙古黄芪Astragalus membranaceus var.mongholicus为材料,解析其叶绿体基因组的序列特征,并进行系统发育分析.方法 利用Illumina NovaSeq测序平台对蒙古黄芪叶绿体全基因组进行测序,完成其组装、注释、特征分析,构建系统发育树.结果 蒙古黄芪叶绿体基因组全长为123 349bp,GC含量为34.09％,由于缺失反向重复IR区,Circos图呈现出非典型四分体结构,属于IRLC群体.获得注释基因109个,其中蛋白编码基因76个,rRNA基因4个,tRNA基因29个.蒙古黄芪叶绿体基因组的密码子偏好性较弱,密码子偏向使用A碱基和U碱基.MISA检测出263个SSR位点,以A/T重复为主;叶绿体全基因组比较分析可知17种豆科植物叶绿体基因组的基因区间组成差异较小;但trnF-GAA～trnT-UGU、trnfM-CUA～psbC、trnE～trnD、psbM～rpoB、ycf1和ycf2等编码区存在差异性;系统发育树显示,蒙古黄芪与胶黄芪A.gummifer聚为一类,与阿纳卡黄芪A.nakaianus、膜荚黄芪A.membranaceus具有一定亲缘性.结论 可为开展黄芪属遗传多样性研究、DNA条形码构建和分子鉴定标记开发提供参考.

The genus Wisteria(Fabaceae)is disjunctly distributed in eastern Asian and eastern North American temperate deciduous forests,and it is widely cultivated around the world as spectacular garden plants.It is a member of inverted repeat-lacking clade(IRLC).The IRLC Species are characterized by the loss of an IR region in their plastomes,which has long been of great interest.In this research,we report whole plastome sequences from all four Wisteria species and a Wisteriopsis japonica,combining these with existing data to explore phylogenetic relationships and biogeography of Wisteria,as well as plastome evolution of IRLC species.Phylogenetic analyses recognized a clade containing Glycyrrhiza-Wisteriopsis-Wisteria as sister to the remaining genera of IRLC.North American Wisteria frutescens and the three Asian species formed reciprocal clades,and Wisteria brachybotrys was sister to Wisteria floribunda and Wisteria sinensis.Wisteria may have originated in Japan near the boundary of the Oligocene and Miocene.The disappearance of Bering Land Bridge in the late Miocene might lead to the Eastern Asian-Eastern North American disjunction of Wisteria.Allopatric speciation of Wisteria between the Japanese archipelago and the Asian continent in the Quaternary increased the species richness of eastern Asia in comparison with eastern North America.Synonymous substitution rates(ds)of protein-coding genes in the IRLC species were around 2-fold(SC genes)or 11-fold(IR genes)higher than those of non-IRLC species.For both SC and IR genes,herbaceous legumes have around 3-fold higher ds than woody ones.Both loss of one IR region and herbaceous habit elevated substitution rates of the plastomes.