Dataset Information

Intraspecific breakdown of self-incompatibility in Physalis acutifolia (Solanaceae).

ABSTRACT: Variation in mating systems is prevalent throughout angiosperms, with many transitions between outcrossing and selfing above and below the species level. This study documents a new case of an intraspecific breakdown of self-incompatibility in a wild relative of tomatillo, Physalis acutifolia. We used controlled greenhouse crosses to identify self-incompatible (SI) and self-compatible (SC) individuals grown from seed sampled across seven sites across Arizona and New Mexico. We measured 14 flower and fruit traits to test for trait variation associated with mating system. We also quantified pollen tube growth in vivo and tested for the presence of the S-RNase proteins in SI and SC styles. We found that seed from six of the seven sites produced SI individuals that terminated self-pollen tubes in the style and showed detectable S-RNase expression. By contrast, seed from one Arizona site produced SC individuals with no S-RNase expression. These SC individuals displayed typical selfing-syndrome traits such as smaller corollas, reduced stigma-anther distances, and a smaller pollen-ovule ratio. We also found plasticity in self-incompatibility as most of the SI individuals became SC and lost S-RNase expression roughly after 6 months in the greenhouse. While fixed differences in mating systems are known among the SI wild species and the often SC domesticated tomatillos, our study is the first to demonstrate intraspecific variation in natural populations as well as variation in SI over an individual's lifespan.

SUBMITTER: Pretz C

PROVIDER: S-EPMC8783618 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Background and aimsUnilateral incompatibility (UI) occurs when pollinations between species are successful in one direction but not in the other. Self-incompatible (SI) species frequently show UI with genetically related, self-compatible (SC) species, as pollen of SI species is compatible on the SC pistil, but not vice versa. Many examples of unilateral incompatibility, and all those which have been studied most intensively, are found in the Solanaceae, particularly Lycopersicon, Solanum, Nicotiana and Petunia. The genus Capsicum is evolutionarily somewhat distant from Lycopersicon and Solanum and even further removed from Nicotiana and Petunia. Unilateral incompatibility has also been reported in Capsicum; however, this is the first comprehensive study of crosses between all readily available species in the genus.MethodsAll readily available (wild and domesticated) species in the genus are used as plant material, including the three genera from the Capsicum pubescens complex plus eight other species. Pollinations were made on pot-grown plants in a glasshouse. The number of pistils pollinated per cross varied (from five to 40 pistils per plant), depending on the numbers of flowers available. Pistils were collected 24 h after pollination and fixed for 3-24 h. After staining, pistils were mounted in a drop of stain, squashed gently under a cover slip and examined microscopically under ultra-violet light for pollen tube growth.Key resultsUnilateral incompatibility is confirmed in the C. pubescens complex. Its direction conforms to that predominant in the Solanaceae and other families, i.e. pistils of self-incompatible species, or self-compatible taxa closely related to self-incompatible species, inhibit pollen tubes of self-compatible species.ConclusionsUnilateral incompatibility in Capsicum does not seem to have arisen to prevent introgression of self-compatibility into self-incompatible taxa, but as a by-product of divergence of the C. pubescens complex from the remainder of the genus.

Project description:BACKGROUND:Fabaceae species are important in agronomy and livestock nourishment. They have a long breeding history, and most cultivars have lost self-incompatibility (SI), a genetic barrier to self-fertilization. Nevertheless, to improve legume crop breeding, crosses with wild SI relatives of the cultivated varieties are often performed. Therefore, it is fundamental to characterize Fabaceae SI system(s). We address the hypothesis of Fabaceae gametophytic (G)SI being RNase based, by recruiting the same S-RNase lineage gene of Rosaceae, Solanaceae or Plantaginaceae SI species. RESULTS:We first identify SSK1 like genes (described only in species having RNase based GSI), in the Trifolium pratense, Medicago truncatula, Cicer arietinum, Glycine max, and Lupinus angustifolius genomes. Then, we characterize the S-lineage T2-RNase genes in these genomes. In T. pratense, M. truncatula, and C. arietinum we identify S-RNase lineage genes that in phylogenetic analyses cluster with Pyrinae S-RNases. In M. truncatula and C. arietinum genomes, where large scaffolds are available, these sequences are surrounded by F-box genes that in phylogenetic analyses also cluster with S-pollen genes. In T. pratense the S-RNase lineage genes show, however, expression in tissues not involved in GSI. Moreover, levels of diversity are lower than those observed for other S-RNase genes. The M. truncatula and C. arietinum S-RNase and S-pollen like genes phylogenetically related to Pyrinae S-genes, are also expressed in tissues other than those involved in GSI. To address if other T2-RNases could be determining Fabaceae GSI, here we obtained a style with stigma transcriptome of Cytisus striatus, a species that shows significant difference on the percentage of pollen growth in self and cross-pollinations. Expression and polymorphism analyses of the C. striatus S-RNase like genes revealed that none of these genes, is the S-pistil gene. CONCLUSION:We find no evidence for Fabaceae GSI being determined by Rosaceae, Solanaceae, and Plantaginaceae S-RNase lineage genes. There is no evidence that T2-RNase lineage genes could be determining GSI in C. striatus. Therefore, to characterize the Fabaceae S-pistil gene(s), expression analyses, levels of diversity, and segregation analyses in controlled crosses are needed for those genes showing high expression levels in the tissues where GSI occurs.

Dataset Information

Intraspecific breakdown of self-incompatibility in Physalis acutifolia (Solanaceae).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets