Long-read bitter gourd (Momordica charantia) genome and the genomic architecture of nonclassic domestication

ArticleProceedings of the National Academy of Sciences. 117(25): 14543-14551. (2020)journal articl

Dissecting the all-hermaphrodite phenomenon of a rare X chromosome mutant in papaya (Carica papaya L.)

Sex form is one of the most important characters in papaya cultivation in which hermaphrodite is preferable sex form. However, sex determination is impossible until flowering. This study has developed SCAR markers derived from the SVP-like gene and can truly discriminate the three sex forms: female, male, and hermaphrodite papaya. Molecular markers were applied to study the mechanisms responsible for the all-hermaphrodite phenomenon in the self-pollinated progeny of “H*-TSS No.7,” an inbred line derived from a rare X chromosome mutant SR*. This study has provided evidence to support that “H*-TSS No.7” contained a recessive lethal allele, ml, on the X chromosome, and the X*X* homozygous genotype (ml/ml) was detected only in seeds but not in seedlings. Consequently, lost germination ability rather than seed abortion was responsible for missing female progeny in the selfed “H*-TSS No.7” population. The lethal effect in genotypes of YY, YYh, and YhYh papaya could be explained by at least one functional X chromosome being necessary for seed development. This study has demonstrated that “H*-TSS No.7” with a lethal allele (ml) on its X* chromosome is the cause of the defect of germinating ability in its homozygous female progeny

Female flower frequency and GTFL-1 genotype in F₂ population.

<p>For 160 F₂ plants from OHB61-5x OHB95-1A, the frequency of female flowers and GTFL-1 genotype in each plant was investigated, and the scoring results are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0087138#pone.0087138.s008" target="_blank">Table S5</a>. The average frequency of female flowers (%) is indicated in the plants for each GTFL-1-genotype: “A” for the homozygotes of the OHB95-1A-type, “G” for the homozygotes of the OHB61-5-type and heterozygotes.</p

Genetic map of putative gynoecious locus (<i>Mcgy</i>).

<p>The genetic distances and location between each RAD-tag marker and the <i>Mcgy</i> locus were calculated from the genotypes of 55 gynoecious F₂ plants. The sequences of alleles in these markers are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0087138#pone-0087138-t004" target="_blank">Table 4</a> (GTFL-1, GTFL-2, GTFL-3, GTFL-11, GTFL-13) and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0087138#pone.0087138.s005" target="_blank">Table S2</a> (GT1998).</p

Summary of RAD-seq analysis of parental lines and bulked F₂ samples using AseI.

<p>Summary of RAD-seq analysis of parental lines and bulked F₂ samples using AseI.</p