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A telomere-to-telomere gap-free reference genome of watermelon and its mutation library provide important resources for gene discovery and breeding.
- Source :
-
Molecular Plant (Cell Press) . Aug2022, Vol. 15 Issue 8, p1268-1284. 17p. - Publication Year :
- 2022
-
Abstract
- Watermelon, Citrullus lanatus , is the world's third largest fruit crop. Reference genomes with gaps and a narrow genetic base hinder functional genomics and genetic improvement of watermelon. Here, we report the assembly of a telomere-to-telomere gap-free genome of the elite watermelon inbred line G42 by incorporating high-coverage and accurate long-read sequencing data with multiple assembly strategies. All 11 chromosomes have been assembled into single-contig pseudomolecules without gaps, representing the highest completeness and assembly quality to date. The G42 reference genome is 369 321 829 bp in length and contains 24 205 predicted protein-coding genes, with all 22 telomeres and 11 centromeres characterized. Furthermore, we established a pollen-EMS mutagenesis protocol and obtained over 200 000 M1 seeds from G42. In a sampling pool, 48 monogenic phenotypic mutations, selected from 223 M1 and 78 M2 mutants with morphological changes, were confirmed. The average mutation density was 1 SNP/1.69 Mb and 1 indel/4.55 Mb per M1 plant and 1 SNP/1.08 Mb and 1 indel/6.25 Mb per M2 plant. Taking advantage of the gap-free G42 genome, 8039 mutations from 32 plants sampled from M1 and M2 families were identified with 100% accuracy, whereas only 25% of the randomly selected mutations identified using the 97103v2 reference genome could be confirmed. Using this library and the gap-free genome, two genes responsible for elongated fruit shape and male sterility (ClMS1) were identified, both caused by a single base change from G to A. The validated gap-free genome and its EMS mutation library provide invaluable resources for functional genomics and genetic improvement of watermelon. A gap-free genome of the elite watermelon inbred line G42 was assembled, with all 22 telomeres and 11 centromeres characterized. Over 200 000 M1 seeds were generated from G42 using pollen-EMS mutagenesis, and more than 301 mutants with morphological changes were confirmed and sequenced from the sampled M1 and M2 populations. The gap-free genome and its EMS mutation library provide important resources for watermelon genetics, genomics, and improvement. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 16742052
- Volume :
- 15
- Issue :
- 8
- Database :
- Academic Search Index
- Journal :
- Molecular Plant (Cell Press)
- Publication Type :
- Academic Journal
- Accession number :
- 158368384
- Full Text :
- https://doi.org/10.1016/j.molp.2022.06.010