Identification of the molecular origin and development of a panzootic caused by Beauveria bassiana in praying mantis populations in eastern China

A panzootic in praying mantid species Tenodera sinensis and Statilia maculate, caused by Beauveria bassiana, occurred in north, southwest and southeast regions of Anhui Province, eastern China in Autumn, 2009. A 3-d principal component analysis (PCA) of 123 isolates from three sites revealed that the B. bassiana populations were heterogeneous with obvious dominance. Furthermore, the causal source of the panzootic in Anhui was shown to be polyphyletic. The populations were homogenized into homogenous subunits for investigation of genetic structure by inter-simple sequence repeat (ISSR) markers. Variance was greater than 70%, largely due to genetic differences within populations and subpopulations. Genetic distances and genetic differentiation were negatively associated with geographic distances and it was speculated that this was due to the effects of monsoons and topography. Mantid isolates were divided into five pathotypes based on a two-way cluster analysis of genetic distance. Pathotype I consisted of the predominant subpopulations of Huangcangyu and Chashui populations, with a genetic distance of 0.120 and gene flow up to 1.833. This pathotype caused a widespread epizootic in north and southwest Anhui, and Pathotype III caused enzootic at Site A in September and then epizootic in October, while the other three pathotypes caused enzootics at all three investigation sites. The widespread epizootics and isolated enzootics composed the polyphyletic panzootic in Anhui. A strong gene flow between isolates from the two mantid species was identified, resulting in negligible gene differentiation. This indicated a lack of host specificity in mantid isolates of B. bassiana.     

球孢白僵菌种内比较线粒体基因组学分析

【目的】明确球孢白僵菌种内线粒体基因组的分化程度。【方法】从GenBank下载已知的球孢白僵菌6个菌株线粒体基因组序列,详细分析基因组的组成结构,比较外显子区、内含子区和基因间区的碱基变异情况,分析菌株间的系统发育关系。【结果】球孢白僵菌不同菌株的线粒体基因组大小为28.8–32.3 kb,都有14个常见的核心蛋白编码基因、2个rRNA基因和25个tRNA基因,具有很强的共线性关系。但是,不同菌株含有的线粒体内含子数目存在差异(2–5个/菌株),在cox1、cox2和nad1基因中表现出内含子插入/缺失多态性,这是导致线粒体基因组大小变化的主要因素。对外显子、内含子和基因间区的碱基变异情况进行分析,发现内含子和基因间区相对变异较大,而外显子区相对变异较小。系统发育分析发现,这些球孢白僵菌菌株以很高的支持度聚在一起,具有相同内含子分布规律的菌株也具有较近的聚类关系。【结论】本研究首次报道球孢白僵菌因内含子数目不同、插入缺失突变和单核苷酸变异等在线粒体基因组上表现出较大程度的遗传分化,为认识真菌种内线粒体基因组分化提供了新的证据。     

Diversity analysis of Beauveria bassiana isolated from infected silkworm in southwest China based on molecular data and morphological features of colony

Beauveria bassiana is an important entomopathogenic fungus that not only often causes infection and epidemics of wild insects but some strains also show pathogenicity to the silkworm, Bombyx mori. The present study is about diversity of B. bassiana isolated from the silkworm in southwest China. Five strains of B. bassiana were isolated from infected silkworm. Two isolates, GXtr1009 and GXtr1010, were isolated from infected silkworms treated with two kinds of biological pesticides applied in Guangxi province, and three isolates, SCsk1006, YNsk1106 and GXsk1011, were collected from naturally infected silkworms from different geographical locations in Yunnan and Sichuan. All of the isolates showed highly similar conidia and conidial fructification, but the colony characteristics demonstrated great differences among the isolates. The ITS and 18S rDNA sequence analysis was sufficient to identify all five isolates as B. bassiana. However, the dendrogram, based on the ISSR data, produced two large genetic groups. GXtr1009 and GXtr1010 comprised one group, and SCsk1006, YNsk1106 and GXsk1011 converged in a different large group. The results suggested that, although all of these five B. bassiana strains were pathogenic to silkworms, strains of biological pesticides could be differentiated from strains of naturally infected silkworm via ISSR analysis.     

濒危特有种掌叶木的微卫星遗传多样性研究

掌叶木居群具有较丰富的遗传多样性,该研究利用9对微卫星(SSR)分子标记揭示了掌叶木(Handeliodendron bodinieri)的遗传多样性。结果表明:观测等位基因数(Na)平均为3.903,有效等位基因数(Ne)平均为2.545,期望杂合度(He)平均为0.521,Shannon’s多态性信息指数(I)为0.962,PIC平均值为0.465。掌叶木的自然分布居群有相对较高的遗传多样性,但由于人为破坏等因素导致该群体濒危,而濒危并不是因为遗传多样性降低而造成的。居群间的遗传分化为掌叶木8个居群间的遗传一致度为(GI=0.849~0.970),遗传距离为(GD=0.032~0.164)。基于Nei’s遗传距离用UPGMA法对掌叶木居群进行聚类,Nei’s的基因分化系数为(G_(st))为0.027,平均Nei标准遗传分化系数(G'_(st)N)为0.031,平均Herick’s标准遗传分化系数(G'_(st)H)为0.064,基因流(N_m)为3.368。AMOVA分析结果表明:掌叶木居群间变异占3%,居群内变异占97%,居群内的遗传分化大于居群间的分化。利用Mantel检测发现,居群间的遗传距离与地理距离显著正相关(r=0.299,P0.05)。该研究结果为掌叶木生物多样性和资源保护与利用提供了更充分的科学依据。     

Comparison of Botrytis cinerea populations isolated from two open-field cultivated host plants

The necrotrophic fungus Botrytis cinerea is reported to infect more than 220 host plants worldwide. In phylogenetical–taxonomical terms, the pathogen is considered a complex of two cryptic species, group I and group II. We sampled populations of B. cinerea on sympatric strawberry and raspberry cultivars in the North-East of Hungary for three years during flowering and the harvest period. Four hundred and ninety group II B. cinerea isolates were analyzed for the current study. Three different data sets were generated: (i) PCR-RFLP patterns of the ADP-ATP translocase and nitrate reductase genes, (ii) MSB1 minisatellite sequence data, and (iii) the fragment sizes of five microsatellite loci. The structures of the different populations were similar as indicated by Nei's gene diversity and haplotype diversity. The F statistics (F_st, G_st), and the gene flow indicated ongoing differentiation within sympatric populations. The population genetic parameters were influenced by polymorphisms within the three data sets as assessed using Bayesian algorithms. Data Mining analysis pointed towards the five microsatellite loci as the most defining markers to study differentiation in the 490 isolates. The results suggest the occurrence of host-specific, sympatric divergence of generalist phytoparasites in perennial hosts.     

POPULATION VARIATION,OUTCROSSING, AND COLONIZATION OF DISTURBED AREAS BY CALAMAGROSTIS CANADENSIS: EVIDENCE FROM ALLOZYME ANALYSIS

Calamagrostis canadensis (a rhizomatous grass) exists in temperate forest sites of different successional age. It can rapidly colonize disturbed sites to form dense swards. We examined allozyme variation in: four populations (mature forest, intermediate aged forest, forest cutblock, wetland); nine small plots (2 m × 4 m) within the cutblock; and progeny of several families from three populations; in order to assess the mode of colonization of disturbed areas and the effect of successional changes on population genetic structure. All four populations showed equal and extensive genetic variation (1.5 to 1.7 alleles per locus [K], 41.7% to 50% polymorphic loci [PPL], H_st = 0.155 to 0.208) and were not genetically differentiated (G_st = 0.0193, 1 = 0.986 to 0.997). The cutblock subpopulations also showed considerable genetic variation (K = 1.6 to 1.8, PPL = 50% to 58.3%, H_st = 0.151 to 0.278) and no microdifferentiation (G_st = 0.034, I = 0.967 to 0.997). We found 14 different genotypes among the 30 individuals sampled from the cutblock as a whole (based on five polymorphic loci). The cutblock subpopulations had from nine to 14 different genotypes each (same five loci, 18 individuals per subpopulation). Seed produced was primarily outcrossed (multilocus estimate 0.888 to 0.900). We concluded that disturbed sites are colonized primarily by sexually produced seedlings. Potential genetic drift and natural selection, which occur during subsequent successional changes, do not result in reduced genetic variation or population differentiation.     

皖南与皖西南蚕区球孢白僵菌种群遗传结构的ISSR分析

由球孢白僵菌引起的家蚕白僵病是影响蚕业生产的重要因素之一.本研究在皖南泾县和皖西南潜山县蚕区的病蚕、蚕室环境、蚕室周边桑园、松林及农田调查取样,共分离出124株球孢白僵菌;通过ISSR分子标记对它们及用于防治松毛虫的菌株进行种群遗传结构分析,追踪家蚕白僵病的来源及传播途径.结果表明： 两个地区的球孢白僵菌种群均为异质性明显的种群.潜山的蚕病亚种群是多源的,而泾县的蚕病亚种群是单源的;泾县蚕病亚种群和潜山的蚕病优势亚种群具有典型的地方性,只在蚕室内循环侵染家蚕,引起低频常在性的地方性白僵病;而潜山的非优势亚种群可以在蚕室外的少数转主寄主中传播.在两地松林的松毛虫种群中流行的类群、真菌杀虫剂生产菌株以及在潜山蚕室附近引起螳螂种群流行病的类群均与蚕病类群无关,表明其对蚕业是安全的.     

Genetic diversity and spatial structure in the rare,endemic orophyte Campanula pseudostenocodon Lac. (Apennines,Italy), as inferred from nuclear and plastid variation

Abstract

Analysis of ISSR markers revealed a large variation within samples, with polymorphic loci (P) ranging from 42 to 82%, in relation to population size. A consistent genetic differentiation (G_st = 0.207; Φ_st 29.71%) was found among the four examined populations. Based on changes in the chloroplast trn ^LEU intron, three distinct haplotypes were identified. Three out of the four populations were fixed for a single haplotype, with the two northernmost populations, which are geographically closest (65 km apart), sharing the same one. These findings suggest that a relatively long period of restricted gene flow originated the present-day spatial structure of C. pseudostenocodon. Application of both nuclear and organelle markers in estimating genetic diversity may be advisable in conservation studies, since they may reveal a peculiar local diversity.     

白芨SSR引物筛选及群体遗传多样性研究

白芨(Bletilla striata Rchb.)为中国珍稀濒危植物,重要的药用植物。该研究基于Illumina测序技术构建白芨基因组文库和微卫星文库,设计白芨微卫星引物,用白芨4个野生种群80个个体对引物进行多态性检测,应用4个白芨近缘种中进行引物的通用性检测,并在此基础上分析了白芨的遗传多样性和遗传分化,以探讨白芨的遗传结构和进化潜能。结果表明:(1)白芨基因组中微卫星片断丰富,共检测出17 841条微卫星片断。基于白芨微卫星库对100个位点设计了引物对,经PCR扩增和检测筛选出能够稳定扩增的多态性位点20个,每个位点的复等位基因数(Na)在2~6之间,平均为3.85;20对引物的大部分能够在4个白芨近缘种中成功扩增。(2)白芨在物种水平均有较高的遗传多样性(Na=3.85,I=1.07,H=0.614 7),白芨种群遗传分化强烈(Gst=0.43),居群间的基因流较弱(Nm=0.867 6),居群聚类分析结果均表明地理距离较近的居群具有较近的遗传关系。     

Molecular genetic relationships among east Palaerctic ground squirrels of the genus <Emphasis Type="Italic">Spermophilus</Emphasis> (Sciuridae,Rodentia)

Abstact  Genetic diversity in the four east Palearctic ground squirrel species of the genus Spermophilus—S. undulatus, S. parryi (subgenus Urocitellus), S. dauricus, and S. relictus (subgenus Citellus)—was investigated using RAPD PCR with ten random primers. Siberian chipmunk, Tamias sibiricus, was used as an out-group. Molecular markers for different taxonomic ranks were identified, including those for the genera Spermophilus and Tamias, subgenera Urocitellus and Citellus, as well as for each of the four species, S.undulatus, S. parryi, S. dauricus, and S. relictus. For the ground squirrel species and subgenera, genetic differentiation indices (H _t, H _s, D _st, G _st,Nm, and D) were calculated. In addition, for these groups the NJ phylogenetic reconstructions and UPGMA dendrograms of genetic similarity of the individuals and combined populations were constructed. Comparative molecular genetic analysis revealed a high genetic differentiation between S. undulatus, S. dauricus, S. relictus, and S. parryi (G _st= 0.58 to 0.82; D= 0.53 to 1.06), along with a low level of genetic differentiation of the subgenera Citellus and Urocitellus (G _st = 0.33; D= 0.27), distinguished in accordance with the existing taxonomic systems of the genus Spermophilus Original Russian Text ? M.V. Tsvirka, L.N. Spiridonova, V.P. Korablev, 2008, published in Genetika, 2008, Vol. 44, No. 8, pp. 1108–1116.     

Genetic diversity of the endangered Chinese endemic herb Primulina tabacum (Gesneriaceae) revealed by amplified fragment length polymorphism (AFLP)

Primulina tabacum Hance, is a critically endangered perennial endemic to limestone area in South China. Genetic variability within and among four extant populations of this species was assessed using AFLP markers. We expected a low genetic diversity level of this narrowly distributed species, but our results revealed that a high level of genetic diversity remains, both at population level (55.5% of markers polymorphic, H _E = 0.220, I _S = 0.321), and at species level (P = 85.6% of markers polymorphic, H _E = 0.339, I _S = 0.495), probably resulting from its refugial history and/or breeding system. High levels of genetic differentiation among populations was apparent based on Nei’s genetic diversity analysis (G _st=0.350). The restricted gene flow between populations is a potential reason for the high genetic differentiation. The population genetic diversity of P. tabacum revealed here has clear implications for conservation and management. To maintain present levels of genetic diversity, in situ conservation of all populations is necessary.     

Genetic diversity and gene flow estimates among three populations of Botryodiplodia theobromae causing die-back and bark canker of pear in Punjab

Three populations of Botryodiplodia theobromae causing die-back and bark canker of pear in Punjab were analysed to know about the genetic diversity, gene flow, heterogeneity and the probable rate of spread of races capable of overcoming the resistance present in elite cultivars. There was no relationship between the morphologically similar isolates and their pathogenic behaviour. Majority of the isolates of B. theobromae within and among the populations produced lesions of 1.9–7.2 × 0.8–3.1 cm size on detached pear twigs cv. Punjab Beauty. Incubation period and per cent infection also varied within and among the three populations of the pathogen. The genetic diversity was calculated on the basis of allele frequencies of nine simple sequence repeat (SSR) markers using Nei's genetic diversity formulae. Allele frequencies (X_ij ) varied significantly among the three populations ranging from 0.0 to 1.0. The mean genetic diversities within population (H _S) also varied in all the locations ranging from 0.18 to 0.36 indicating a high genetic diversity within the population. The total genetic diversity across all the populations (H _T) ranged between 0.1 and 0.5 with a mean of 0.36, and differed significantly from the mean H _S (0.25). Diversity indices of SSR loci varied from low (H _S < 0.1) to high (H _S > 0.4) across all the populations (G _ST) of B. theobromae in Punjab which were consistent over the presumed SSR loci with a mean G _ST of 0.29. The lower G _ST values of 0.13, 0.10, 0.11 and 0.13 were observed at LAS15-16, LAS27-28, BOT17-18 and BOT35-36 loci, respectively, showing high genetic diversity among all the isolates. However, at BOT19-20 locus, the G _ST value observed was 0.72 thereby indicating low diversity in the population at this locus. Out of 25 loci, 8 loci showed the gene flow (Nm) < 1 indicating a high genetic differentiation within the population and the remaining 6 loci showed the Nm > 1 indicating the frequent existence of gene flow across the populations of B. theobromae. Pairwise comparison (G _ST) values among all the loci were ranging from 0.18 to 0.19, which indicate a low genetic differentiation among the populations of B. theobromae. The high genetic diversity (H _S) within the population was observed in the present study suggesting that B. theobromae possess high variability in Punjab. Keeping this in view, new races would be expected soon outside the state of origin, as naturally occurring gene flow is likely to be increased by the human activity for comprehensive cultivation of pear in the near future. Therefore, it is difficult to predict the durability of resistant sources in Punjab, which in turn emphasises the identification and introgression of R genes into commercial cultivars.     

A population survey of Beauveria bassiana in the microhabitat of the red turpentine beetle,Dendroctonus valens,in Chinese pine forests

Field survey of the entomopathogenic fungus Beauveria bassiana in association with the red turpentine beetle, Dendroctonus valens, was undertaken in three pine plantations in Northern China. In total, 88 strains of B. bassiana sensu lato were isolated from the soil, bark, beetle frass, living adult and cadaver samples and soil was proved to be an important inoculum reservoir for fungal entomopathogens. Of these, 77 isolates were included for genetic diversity analysis by PCR for inter-simple sequence repeats (ISSR). Genetic diversity and population structure analysis of the isolates from three sites and five niches demonstrated high genetic diversity and heterogeneity between and/or within populations. Wright's statistics revealed a high gene flow rate (4.529) among the three populations, especially among the soil-derived isolate subpopulations. Low variation was mainly caused (94.8%) by variation among different substrates, suggesting the importance of microhabitat substrates on genetic diversity of B. bassiana. Phylogenetic variation was not associated with geographic distance.     

The phylogeography of Fagus hayatae (Fagaceae): genetic isolation among populations

The beech species Fagus hayatae is an important relict tree species in subtropical China, whose biogeographical patterns may reflect floral responses to climate change in this region during the Quaternary. Previous studies have revealed phylogeography for three of the four Fagus species in China, but study on F. hayatae, the most sparsely distributed of these species, is still lacking. Here, molecular methods based on eight simple sequence repeat (SSR) loci of nuclear DNA (nDNA) and three chloroplast DNA (cpDNA) sequences were applied for analyses of genetic diversity and structure in 375 samples from 14 F. hayatae populations across its whole range. Both nDNA and cpDNA indicated a high level of genetic diversity in this species. Significant fixation indexes and departures from the Hardy–Weinberg equilibrium, with a genetic differentiation parameter of R_st of 0.233, were detected in nDNA SSR loci among populations, especially those on Taiwan Island, indicating strong geographic partitioning. The populations were classified into two clusters, without a prominent signal of isolation‐by‐distance. For the 15 haplotypes detected in the cpDNA sequence fragments, there was a high genetic differentiation parameter (G_st = 0.712) among populations. A high G_st of 0.829 was also detected outside but not within the Sichuan Basin. Consistent with other Fagus species in China, no recent population expansion was detected from tests of neutrality and mismatch distribution analysis. Overall, genetic isolation with limited gene flow was prominent for this species and significant phylogeographic structures existed across its range except for those inside the Sichuan Basin. Our study suggested long‐term geographic isolation in F. hayatae with limited population admixture and the existence of multiple refugia in the mountainous regions of the Sichuan Basin and southeast China during the Quaternary. These results may provide useful information critical for the conservation of F. hayatae and other Chinese beech species.     

Analysis of population genetic structure of two closely related tortricid species of economic importance on macadamias and litchis in South Africa

Abstract

• 1 The macadamia nut borer Thaumatotibia (Cryptophlebia) batrachopa and the litchi moth Cryptophlebia peltastica are Afrotropical species causing extensive damage to cultivated macadamias and litchis in the northernmost provinces in South Africa. Cryptophlebia peltastica also occurs as natural populations throughout the country.
• 2 To analyse the population genetic structure of the two species, amplified fragment length polymorphism analysis was conducted. Patterns of genetic diversity in C. peltastica populations in the Mpumalanga province, where the species is controlled, were compared with those in the Western Cape, where populations occur under natural conditions.
• 3 Gene diversity was high within T. batrachopa populations (H = 0.2219) with significant genetic differentiation among populations (G_st = 0.358). Cluster analysis showed that geographical populations were closely related and extensive divergence was found over local scales.
• 4 Similar to that of T. batrachopa, genetic diversity and population differentiation was high within both C. peltastica Mpumalanga and Western Cape populations (H = 0.1906 and 0.1687 and G_st = 0.4124 and 0.3799, respectively).
• 5 It is suggested that the population genetic structure of both species is influenced by their limited ability to disperse. In addition, chemical control of C. peltastica in the Mpumalanga province has not succeeded in reducing the population size, but the C. peltastica population subdivision in the Western Cape may be influenced by the limited distribution of host plants in this region.

     

The molecular diversity of different isolates of <Emphasis Type="Italic">Beauveria bassiana</Emphasis> (Bals.) Vuill. as assessed using intermicrosatellites (ISSR<Subscript>s</Subscript>)

Inter-microsatellite PCR (ISSR-PCR) markers were used to identify and to examine the genetic diversity of eleven Beauveria bassiana isolates with different geographic origins. The variability and the phylogenetic relationships between the eleven strains were analyzed using 172 ISSR-PCR markers. A high level of polymorphism (near 80%) was found using these molecular markers. Seven different isolates showed exclusive bands, and ISSR primer 873 was able to distinguish between all the strains. The dendrogram obtained with these markers is robust and in agreement with the geographical origins of the strains. All the isolates from the Caribbean region were grouped together in a cluster, while the other isolates grouped in the other cluster. The similarity exhibited between the two clusters was less than 50%. This value of homology shows the high genetic variability detected between the isolates from the Caribbean region and the other isolates. ISSR-PCR markers provide a quick, reliable and highly informative system for DNA fingerprinting, and allowed the identification of the different B. bassiana isolates studied.     

北沙柳群体遗传多样性和遗传结构分析

以内蒙古北沙柳(Salix psammophila)国家种质资源库内9个群体(P1~P9)288个无性系为实验材料,利用TP-M13-SSR技术,选取22对具有多态性EST-SSR北沙柳引物,采用毛细管电泳对PCR产物进行检测,分析北沙柳遗传多样性、分化程度和群体遗传结构,为北沙柳种质资源库遗传管理、无性系鉴定、品种选育、遗传改良和构建指纹图谱提供理论依据。结果显示:(1)22对EST-SSR引物共检测到222个等位基因,各位点平均等位基因数(A)为10,四倍体基因型丰富度(G)和特异基因型(G1)总和分别为1 460和802个,平均特异基因型比率(P1)和种质鉴别率(P2)分别为45.86%和13.21%。(2)9个群体平均等位基因数(A)为7.475,基因型丰富度(G)为15.586,观察杂合度(Ho)和期望杂合度(He)分别为0.577和0.638。以期望杂合度He为标准,北沙柳群体遗传多样性水平最低的是P1和P9。(3)北沙柳群体遗传分化系数仅为0.02,AMOVA分子变异分析显示,北沙柳群体大部分遗传变异来自群体内(97%),群体间变异仅为3%。(4)三维主成分、聚类和Structure群体遗传结构分析显示,9个群体被划分为2个组,Mantel检验表明北沙柳遗传距离与地理距离极显著相关(r=0.684 P0.001)。研究表明,北沙柳种质资源具有丰富的遗传多样性,这是其具有耐旱、耐寒、耐高温、耐沙埋和抗风蚀等适应性较强的分子基础;北沙柳的遗传变异集中在群体内;分布区群体呈现由中心向边缘群体扩张分化的趋势。     

Genetic Variation and Differentiation of Peat-Bog and Dry-Meadow Populations of the Dwarf Mountain Pine Pinus mugo Turra in the Highlands of the Ukrainian Carpathians

Based on electrophoretic analysis of 21 isozyme loci controlling 10 enzyme systems, the intra- and interpopulation variation was studied in two peat-bog and three dry-meadow populations of the dwarf mountain pine Pinus mugoTurra from the highlands of the Ukrainian Carpathians. In the studied samples (a total of 164 trees), on average 62% of the studied genes were polymorphic; the mean heterozygosity was 21.3%. The dry-meadow populations differed from the peat-bog populations by allele and genotype diversity and by heterozygosity although the indices characterizing population heterogeneity (F _st and G _st) were small (0.027 and 0.032, respectively). Nei's genetic distances between the populations ranged of 0.011 to 0.032 with the mean of 0.018.     

中国东部沿海水仙归化群体的遗传多样性

为揭示我国东部归化水仙(Narcissus tazetta var. chinensis)的群体遗传多样性,利用2个叶绿体基因mat K和trn H-psb A片段对采自沪、浙、闽的5个代表群体的49株水仙进行了评估。结果表明,双基因联合序列的总长为1443bp,共定义6个单倍型,各归化群体的遗传多样性水平为DLSYPTDNJD=ZZCMD。AMOVA分析表明,群体内变异为遗传变异的主要来源(91.98%),群体间的遗传分化较低(Fst=0.080 22)。群体物种水平上的谱系结构不显著(Nst=0.020Gst=0.031;P0.05)。Mantel检验表明水仙群体间的遗传距离与地理距离呈显著的线性相关(r=0.929,P=0.02 0.05)。中性检验和错配分布分析结果均暗示水仙群体背离了快速扩张模型的假设。单倍型分布的中介网络图结合系统发育NJ树均将所有群体划分为2大分支。因此,我国东部沿海水仙归化群体整体遗传多样性水平较低,各群体间遗传分化较弱,遗传变异主要来自群体内,物种近期未经历扩张事件,可能是基因流受海岛隔离、自身生物学特征、生境异质性与及人为干扰的综合作用影响。