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The level of genetic diversity and differentiation of tropical lotus, Nelumbo nucifera Gaertn. (Nelumbonaceae) from Australia, India, and Thailand.

ABSTRACT: BACKGROUND:Nelumbo nucifera Gaertn., a perennial aquatic macrophyte species, has been cultivated in several Asian countries for its economic importance, and medicinal uses. Two distinct ecotypes of the species are recognized based on the geographical location where the genotypes are adapted, i.e., tropical lotus and temperate lotus. The genetic diversity levels and differentiation of the tropical lotus from poorly studied geographic regions still remain unclear. Here, the population genetic diversity and structure of 15 tropical lotus populations sampled from the previous understudied natural distribution ranges, including India, Thailand, and Australia, were assessed using nine polymorphic SSR markers. RESULTS:The SSR markers used to genotype the 216 individuals yielded 65 alleles. The highest and lowest genetic diversity estimates were found in Thailand and Indian populations, respectively. STRUCTURE analysis revealed three distinct genetic clusters, with relatively low admixtures, supported by PCoA cluster analysis. Low levels of gene flow (mean N?m?=?0.346) among the three genetic clusters signified the Mantel test for isolation by distance, revealing the existence of a positive correlation between the genetic and geographic distances (r?=?0.448, P?=?0.004). Besides, AMOVA analysis revealed a higher variation among populations (59.98%) of the three groups. Overall, the populations used in this study exposed a high level of genetic differentiation (FST?=?0.596). CONCLUSIONS:The nine polymorphic microsatellite markers used in our study sufficiently differentiated the fifteen tropical N. nucifera populations based on geography. These populations presented different genetic variability, thereby confirming that populations found in each country are unique. The low genetic diversity (HE?=?0.245) could be explained by limited gene flow and clonal propagation. Conserving the available diversity using various conservation approaches is essential to enable the continued utilization of this economically important crop species. We, therefore, propose that complementary conservation approaches ought to be introduced to conserve tropical lotus, depending on the genetic variations and threat levels in populations.

SUBMITTER: Mekbib Y

PROVIDER: S-EPMC7229132 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

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The level of genetic diversity and differentiation of tropical lotus, Nelumbo nucifera Gaertn. (Nelumbonaceae) from Australia, India, and Thailand.

Mekbib Yeshitila Y Huang Shi-Xu SX Ngarega Boniface K BK Li Zhi-Zhong ZZ Shi Tao T Ou Ke-Fang KF Liang Yu-Ting YT Chen Jin-Ming JM Yang Xing-Yu XY

Botanical studies 20200516 1

<h4>Background</h4>Nelumbo nucifera Gaertn., a perennial aquatic macrophyte species, has been cultivated in several Asian countries for its economic importance, and medicinal uses. Two distinct ecotypes of the species are recognized based on the geographical location where the genotypes are adapted, i.e., tropical lotus and temperate lotus. The genetic diversity levels and differentiation of the tropical lotus from poorly studied geographic regions still remain unclear. Here, the population gene ...[more]

PMID: 32415549

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Project description:BackgroundAsian lotus (Nelumbo nucifera Gaertn.) is the national flower of India, Vietnam, and one of the top ten traditional Chinese flowers. Although lotus is highly valued for its ornamental, economic and cultural uses, genomic information, particularly the expressed sequence based (genic) markers is limited. High-throughput transcriptome sequencing provides large amounts of transcriptome data for promoting gene discovery and development of molecular markers.ResultsIn this study, 68,593 unigenes were assembled from 1.34 million 454 GS-FLX sequence reads of a mixed flower-bud cDNA pool derived from three accessions of N. nucifera. A total of 5,226 SSR loci were identified, and 3,059 primer pairs were designed for marker development. Di-nucleotide repeat motifs were the most abundant type identified with a frequency of 65.2%, followed by tri- (31.7%), tetra- (2.1%), penta- (0.5%) and hexa-nucleotide repeats (0.5%). A total of 575 primer pairs were synthesized, of which 514 (89.4%) yielded PCR amplification products. In eight Nelumbo accessions, 109 markers were polymorphic. They were used to genotype a sample of 44 accessions representing diverse wild and cultivated genotypes of Nelumbo. The number of alleles per locus varied from 2 to 9 alleles and the polymorphism information content values ranged from 0.6 to 0.9. We performed genetic diversity analysis using 109 polymorphic markers. A UPGMA dendrogram was constructed based on Jaccard's similarity coefficients revealing distinct clusters among the 44 accessions.ConclusionsDeep transcriptome sequencing of lotus flower buds developed 3,059 genic SSRs, making a significant addition to the existing SSR markers in lotus. Among them, 109 polymorphic markers were successfully validated in 44 accessions of Nelumbo. This comprehensive set of genic SSR markers developed in our study will facilitate analyses of genetic diversity, construction of linkage maps, gene mapping, and marker-assisted selection breeding for lotus.

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Dataset Information

The level of genetic diversity and differentiation of tropical lotus, Nelumbo nucifera Gaertn. (Nelumbonaceae) from Australia, India, and Thailand.

Publications

The level of genetic diversity and differentiation of tropical lotus, Nelumbo nucifera Gaertn. (Nelumbonaceae) from Australia, India, and Thailand.

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