Latin America is a biodiversity hotspot, harboring some of the most exceptional plants on earth in a myriad of microclimates and niches available across the altitudinal range of the Andes. Historically, scientific research on plant reproduction in Latin America has focused on understanding diversification mechanisms, reproductive adaptations, and species distribution. However, more recently, some research groups have turned their focus towards understanding the genetic bases for plant domestication and addressing food security concerns, while others have exploited model species like Arabidopsis thaliana to understand mechanistic aspects of reproduction. We are thrilled to present this special issue on Plant Reproduction Research in Latin America. A compendium of 16 research articles exemplify a wide assortment of approaches to study plant reproduction in numerous model and non-model seed plants.

Strelin et al. use comprehensive analysis of data from the literature as well as field and laboratory studies to test long-standing Darwinian theories regarding the location and developmental timing of male-phase and female-phase flowers on bee-pollinated plants (https://doi.org/10.1007/s00497-023-00480-9).

Kuhn et al. (https://doi.org/10.1007/s00497-023-00473-8) describe a new pattern of pollen tube growth and provide an atlas of seed cone development in South America’s most emblematic gymnosperms of: Araucaria angustifolia. Shifting phylogenetically to flowering plants, Alves Rodrigues et al. (https://doi.org/10.1007/s00497-023-00464-9) identify the mutation responsible for seedless fruits in the early divergent angiosperm Annona squamosa. Their findings offer a foundation for the introgression of the seedless trait into elite sugar apple lines.

Several articles in this collection highlight various aspects of reproduction in monocots such as grasses, sedges, agaves, and orchids. In particular, Madrigal et al. (https://doi.org/10.1007/s00497-023-00482-7) present a comprehensive analyses of gene lineages that control the reproductive transition in one of the most species-rich flowering plant families: the Orchidaceae. These authors also discuss the challenges and pitfalls associated with attempting to extrapolate the genetic network for flowering from grasses to orchids. Hernández-Soriano et al. (https://doi.org/10.1007/s00497-023-00489-0) present a detailed functional characterization of FLOWERING LOCUS T (FT) homologs in agave. The authors conclude that FT genes in agave have diversified in function, with some acting as flowering activators and others as repressors. Their data also support a connection between carbohydrate metabolism and the regulation of the vegetative to reproductive transition in Agave tequilana. Other laboratories in Latin America have focused on assessing changes in closely related species with contrasting mating systems. For instance, Reutemann et al. (https://doi.org/10.1007/s00497-023-00478-3) evaluated morphological and genetic differences between self-sterile Paspalum indecorum and self-fertile P. pumilum. Contrary to expectations, the authors conclude that selfing populations show higher morphological variation in vegetative and phenological traits compared to outcrossers. However, at the molecular level, selfing populations showed lower levels of genotypic and genetic diversity than outcrossing populations. Carballo et al. (https://doi.org/10.1007/s00497-023-00490-7) addressed genetic and epigenetic differences between diploidized and tetraploidized Eragrostis curvula genotypes. In the comparisons between sexual and apomictic genotypes, the authors identified differentially methylated genes involved in the reproductive pathways, specifically in meiosis, cell division, and fertilization. Reproduction in sedges is assessed on two fronts: Rocha et al. (https://doi.org/10.1007/s00497-023-00477-4) explore the microspore and pollen grain throughout development, while Reutemann et al. (https://doi.org/10.1007/s00497-023-00465-8) present a comprehensive characterization of structural diversity in fruits and seeds in Cyperaceae. Shifting focus to monocots, Guerrero-Méndez and Abraham-Juárez (https://doi.org/10.1007/s00497-023-00485-4) review mutants and genes identified with a role in establishing floral sex and their relationship with associated hormones such as Jasmonic acid, brassinosteroid and gibberellin.

The remaining manuscripts in this special issue focus on reproduction in eudicots. Two papers address reproduction in one of the most representative and charismatic of American plant families: the Cactaceae. In the study by Ramírez-Castro et al. (https://doi.org/10.1007/s00497-023-00494-3) flower formation and organ differentiation are investigated in Disocactus speciosus and Disocactus eichlamii, documenting initial meristem determination highlighting their relevance to pericarp development and early floral organ formation. In their detailed study, Delbón et al. (https://doi.org/10.1007/s00497-023-00461-y) investigated floral sex determination in Gymnocalicium bruchii, a globose cactus endemic to central Argentina that is presumed to be dioecious or gynodioecious. The authors conclude that G. bruchii is indeed a dioecious species and present ontogenetic evidence of anther collapse before microspore maturation in female flowers and an unfertile gynoecium in male flowers. Focusing on the reproduction of other eudicots, the manuscript of Muniz-Nardelli et al. (https://doi.org/10.1007/s00497-023-00491-6) employs transcriptomics to assess changes in gene expression profiles linked to the reproductive transition in Gossypium hirsutum, the world’s most extensively cultivated fiber crop. Furthermore, aiming to develop new delayed-flowering varieties of alfalfa, Lorenzo et al. (https://doi.org/10.1007/s00497-023-00466-7) characterized three TERMINAL FLOWER 1 (TFL1) genes. These authors conclude that precise manipulation of MsTFL1A gene expression could be a powerful tool to improve alfalfa forage quality. Finally, two laboratories harness the power of genetic tools available for the model Arabidopsis thaliana and assess the genetic basis of previously unexplored reproductive features. For instance, in their study, Tovar-Aguilar et al. (https://doi.org/10.1007/s00497-023-00487-2) use Arabidopsis plants that can give rise to supernumerary surviving megaspores to identify a mechanism mediated by the AGO9-miR822 complex that modulates monosporic female gametogenesis in Arabidopsis thaliana. Finally, Bernal-Gallardo et al. (https://doi.org/10.1007/s00497-023-00493-4) highlight the importance of the EXPANSIN15 gene in promoting cell expansion in floral tissues such as petals and in mediating fusion of the gynoecium medial tissues, leading to formation of the two fused carpels, a characteristic feature of the Arabidopsis fruit.

The articles featured in this special issue offer a comprehensive view of the depth of plant reproduction research in Latin America. Encompassing investigations into speciation and diversity to mechanistic studies of organ development, this special issue aims to foster research in plant reproduction. We hope that this special issue will promote research on plant reproduction, stimulate scientific collaborations between different research groups in Latin America and beyond, and broaden the scope of plant species in which reproduction is studied in more detail.