Genome wide simple sequence repeats development and their application in genetic diversity analysis in wax gourd ( Benincasa hispida )

Abstract Background: Wax gourd (Benincasa hispida Cong., 2n=2x=24) is one of the most important winter vegetables of the Cucurbitaceae family. There are only limited markers available for this crop and the draft genome of wax gourd provides a powerful tool for SSR marker development.Results: In this study, we developed genome-wide SSR markers from wax gourd genome and characterized their distribution and frequency of different motifs and repeats. A total of 52,431 microsatellites from wax gourd genome were identified, of which 39,319 SSR markers were developed. 1,152 non-wax gourd SSR markers were selected from cucumber, melon, watermelon and pumpkin to test their transferability in wax gourd. 580 SSR markers could be transferable in wax gourd, and 42 of them were detected with polymorphic in 11 tested accessions of wax gourd. In addition, 11 good polymorphic transferrable SSR markers and 21 SSR markers of wax gourd were selected to investigate the genetic diversity and population structure of 129 wax gourd accessions. 112 alleles were detected by these 32 SSR markers. The result of population structure showed that the 129 wax gourd accessions were divided into two main populations, and the genetic diversity analysis separated them into two clusters. Conclusions: The large number of wax gourd SSR markers developed in this study provides a valuable resource for genetic linkage map construction, molecular mapping, and marker-assisted selection (MAS) in wax gourd.

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Genome Wide Characterization and Comparative Analysis of Simple Sequence Repeats in Cucurbita Genomes

10.21203/rs.3.rs-40696/v1 ◽

2020 ◽

Author(s):

Lei Zhu ◽

Hua yu Zhu ◽

Yan man Li ◽

Xiang bin Wu ◽

Jin tao Li ◽

...

Keyword(s):

Genetic Diversity ◽

Comparative Genomics ◽

Ssr Markers ◽

Simple Sequence Repeats ◽

Diversity Analysis ◽

Motif Length ◽

Genetic Diversity Analysis ◽

Genome Wide ◽

Ssr Loci ◽

Simple Sequence

Abstract Background The Cucurbita genus contains important economic crops in the world, while limited molecular markers have been developed in the past years. Simple sequence repeats (SSR) markers are powerful tools for the study of genetic mapping construction, genetic diversity analysis and genome wide association. The availability of pumpkin genome information has made it possible to analyze SSRs in genome wide across three Cucurbita species. Results In this paper, based on the whole genome sequences, 34,375 SSR loci were found in C. moschata, 30,577 SSR loci were found in C. maxima and 38,104 SSR loci were found in C. pepo. C. pepo has the maximum density of SSRs with an average of 145 SSR/Mb. In general, the frequency in total SSR loci decreased with the increase of the motif length, dinucleotide motifs were the most common motifs in the three species, and for the same repeat types, the SSR frequency decreased sharply with the increase of the repeat number. Most of those SSR loci were suitable for marker development (84.75% in C. moscata, 94.53% in C. maxima and 95.09% in C. pepo). Based on those markers, we compared and analyzed the cross-species SSR markers between C. pepo and other Cucurbitaceae species by silico-PCR. Using these cross-species primers, the high collinear relationships between C. pepo and the other two species were detected, respectively. Furthermore, the application of SSR markers in genetic diversity analysis was tested in C. pepo, the results showed that they were good tools to be used in genetic diversity analysis. Conclusion In this study, the genome wide SSR markers were detected from three Cucurbita species, and some of their applications were proved by comparative genomics and genetic diversity analysis. The large number of genome-wide SSR markers and crossspecies markers would promote the basic and applied studies of Cucurbita species, such as gene mapping, QTLs mapping, comparative genomics and marker-assisted breeding.

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