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Karyotype of P. vera. Karyotype root-tip metaphase chromosomes of P. vera (n = 15) stained with DAPI (A) showing two larger chromosomes (designated HC1) that are strongly heterochromatic. In situ hybridization using ribosomal DNA probes (red, 45S rDNA, pink, 5S rDNA), PIVE-180 (green) (B), and PIVE-40 (yellow, C). Bar represents 2.5 μm.
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This paper represents the first molecular cytogenetic characterization of the strictly dioecious pistachio tree (Pistacia vera L.). The karyotype was characterized by fluorescent in situ hybridization (FISH) with probes for 5S and 45S rDNAs, and the pistachio specific satellite DNAs PIVE-40, and PIVE-180, together with DAPI-staining. PIVE-180 has a...
Citations
... Research on the sex determination mechanism in P. vera L. has shown that the development of opposite sex primordia is initiated but then arrested in the early stages [12]. Based on sex-associated loci identified in pistachio, a ZZ/ZW sex determination system has been reported, in which the females are the heterogametic sex [6,10,13,14]. Furthermore, there is evidence that the heterogametic sex chromosome system is emerging in the early stage of differentiation given that the heterozygous SNPs markers are present in pistachio females [10]. ...
Pistacia lentiscus var. chia is a valuable crop for its high-added-value mastic, a resin with proven pharmaceutical and cosmeceutical properties harvested from the male tree trunk. To achieve the maximum economic benefits from the cultivation of male mastic trees, it is important to develop early sex diagnosis molecular tools for distinguishing the sex type. Thus far, the work on sex identification has focused on Pistacia vera with promising results; however, the low transferability rates of these markers in P. lentiscus necessitates the development of species-specific sex-linked markers for P. lentiscus var. chia. To our knowledge, this is the first report regarding: (i) the development of species-specific novel transcriptome-based markers for P. lentiscus var. chia and their assessment on male, female and monoecious individuals using PCR-HRM analysis, thus, introducing a cost-effective method for sex identification with high accuracy that can be applied with minimum infrastructure, (ii) the effective sex identification in mastic tree using a combination of different sex-linked ISSR and SCAR markers with 100% accuracy, and (iii) the impact evaluation of sex type on the genetic diversity of different P. lentiscus var. chia cultivars. The results of this study are expected to provide species-specific markers for accurate sex identification that could contribute to the selection process of male mastic trees at an early stage for mass propagation systems and to facilitate future breeding efforts related to sex-linked productivity and quality of mastic resin.
... The results described in reviews of angiosperms (Yampolsky and Yampolsky 1922;Ming et al. 2011) are probably biased toward species with heteromorphism visible to microscopists. The only heteromorphic system discovered since 1958 appears to be in Pistacia (Sola-Campoy et al. 2015;Palmer et al. 2022), though more will probably be discovered as genomes of further dioecious plants are sequenced or through other evidence (see below). ...
Understanding plant sex chromosomes involves studying interactions between developmental and physiological genetics, genome evolution, and evolutionary ecology. We focus on areas of overlap between these. Ideas about how species with separate sexes (dioecious species, in plant terminology) can evolve are even more relevant to plants than to most animal taxa because dioecy has evolved many times from ancestral functionally hermaphroditic populations, often recently. One aim of studying plant sex chromosomes is to discover how separate males and females evolved from ancestors with no such genetic sex-determining polymorphism, and the diversity in the genetic control of maleness vs femaleness. Different systems share some interesting features, and their differences help to understand why completely sex-linked regions may evolve. In some dioecious plants, the sex-determining genome regions are physically small. In others, regions without crossing over have evolved sometimes extensive regions with properties very similar to those of the familiar animal sex chromosomes. The differences also affect the evolutionary changes possible when the environment (or pollination environment, for angiosperms) changes, as dioecy is an ecologically risky strategy for sessile organisms. Dioecious plants have repeatedly reverted to cosexuality, and hermaphroditic strains of fruit crops such as papaya and grapes are desired by plant breeders. Sex-linked regions are predicted to become enriched in genes with sex differences in expression, especially when higher expression benefits one sex function but harms the other. Such trade-offs may be important for understanding other plant developmental and physiological processes and have direct applications in plant breeding.
... There are also monoecious cultivars [153,154]. From the point of view of the evolution of sex and sex chromosomes, this crop is interesting regarding the ZZ/ZW (2n = 30) system of sex chromosomes [155]-that is, the heterogametic sex of the pistachio is female, like birds or some insect species. This system of sex chromosomes is rare in plants. ...
Unlike in animals, dioecy among flowering plants is a rare phenomenon. The vast majority of angiosperm species have a bisexual flower that combines male (androecium) and female (gynoecium) reproductive organs. However, about a quarter of species have dioecious flowers, which can be located within the same plant (monoecious) or on different plants (dioecious). The flower formation in dioecious plants is determined by various genetic mechanisms. They become more complex from the work of a single gene to the functioning of full-fledged heteromorphic sex chromosomes, which can directly affect sex differentiation or participate in the balance determination of sex (where the formation of male or female flower organs depends on the ratio of X chromosomes to autosomes, for example). In recent years, the development of sequencing techniques, bioinformatics, and molecular biology has led to an increase in interest in the sex determination mechanisms among plants. It is noteworthy that a significant number of dioecious plants have economic value. At the same time, dioeciousness often complicates the growing process. This fact increases the relevance of studies on dioecious crops. In this review, we attempt to summarize the current information on sex chromosomes and the mechanisms of sex determination in dioecious plants, concentrating on species with agricultural importance.
... However, not many cytological or molecular studies studies have been carried out to date in nut plant species in general and walnut in particular. They are limited to studies of genetic diversity due to variation in the chromosomes and genome size (Harandi and Ghaffari, 2001;Martinez-Gomez et al., 2003;Rasouli et al., 2014;Vahdati, 2014;Sola-Campoy et al., 2015;Khorami, 2018). Detailed study of the cell division in nuts has not been conducted previously, as well as the nucleolar characteristics (their shape, size and morphology) have not been described. ...
We studied the cytogenetic characteristics of the seed progeny of the walnut (Juglans regia L.) trees introduced to and grown within the territory of the Central Russian Upland. Three seedling groups with polymorphic cytogenetic characteristics were revealed: mutable (with a high level of pathological mitoses), low mutable (with a low level of cytogenetic disturbances), and intermediate groups. Cytogenetic characteristics (mitotic activity, parts of cells at various stages of mitosis, the level and spectrum of pathological mitoses, sizes of nucleoli and the spectrum of their types, the occurrence of cells with a persistent nucleolus in the stages of meta-, ana-, and telophase) in each of the selected groups were described; homeostatic mechanisms at the cellular level were discussed. The sizes of polymorphic groups were established. The small number of seedlings with a high level of cytogenetic disturbances (7.5%) and the predominance of seedlings with medium (70%) and low (22.5%) values of pathological mitoses indicated a high degree of adaptation of the introduced walnut mother trees to the environmental conditions of the Central Russian Upland. Predictors for assigning any seedling to one of the selected model groups (mutable or low mutable) were established using ROC analysis methods. The obtained data on the qualitative and quantitative polymorphism of cytogenetic characteristics can be used for the development of recommendations for improving the system of seed production and the selection of new forms of walnut in the Central Chernozem Region.
... Chromosome counts have been performed in some species of this genus ( Table 2), and the ploidy levels of P. vera (Bochantseva 1972, Fasihi Harandi et al. 1996, Ila et al. 2003, Sola-Campoy et al. 2015, Tilkat et al. 2011, Zohary 1952, P. integerrima (Mehra 1976, Sandhu andMann 1988), P. lentiscus (Natarajan 1977(Natarajan , 1978, P. atlantica (Ila et al. 2003, Vogt and Aparicio 1999, Zerey-Belaskri et al. 2018, P. terebinthus, and P. eurycarpa (Ila et al. 2003) were reported as 2n = 30, whereas those of three subspecies of P. atlantica (cabulica, kurdica, and mutica) were 2n = 28 (Ghaffari and Fasihi Harandi 2002). Additionally, the ploidy levels of P. khinjuk (Ghaffari and Fasihi Harandi 2002) and P. chinensis (Huang et al. 1989) were initially reported as 2n = 28, but Wang (2013), Wu and Yang (2014), and Yang (2013) reported that the ploidy of P. chinensis is 2n = 30. ...
... Nevertheless, all of these SNP markers were heterozygous in the female individuals and homozygous in the male individuals, suggesting a ZW/ZZ sex determination system in P. vera (Kafkas et al. 2015, Khodaeiaminjan et al. 2017. This hypothesis could have been supported by a molecular cytogenetic characterization study that revealed only two types (type-I/II heterozygotes and type-I homozygotes) of pistachio individuals had HC1 chromosomes with differing PIVE-40 hybridization signals (Sola-Campoy et al. 2015). However, the gender of the seeds carrying heteromorphic HC1 pairs was not determined; therefore, the HC1 chromosomes cannot be unambiguously used for sex determination. ...
Generally, Pistacia species are dioecious, but monoecious strains in several populations have been found, providing excellent models for studying sex differentiation and sex determination mechanisms. Although the mechanisms of sex determination and sex evolution have been extensively studied, related research on heterozygous woody plants is limited. Here, we discuss the expressions of various sex types, which showed broad diversity and complex instability. We have also reviewed the sex determination systems in the plant kingdom and the morphological, cytological, physiological, and molecular aspects of the sex-linked markers in Pistacia trees. Moreover, hypotheses to explain the origin of monoecy are discussed, which is more likely to be the interaction between sex-related genes and environment factors in female plants. Besides, further prospects for the utilization of monoecious resources and the research directions of sex determination mechanism are proposed. This study provides important information on sex expression and provides more insights into sex differentiation and determination.
... The divergence and controversy in chromosome count in the genus Pistacia might be due to karyotyping errors. Such controversies in chromosome counting have been attributed to the small size of Pistacia chromosomes and to the fact that only a few cell divisions are visible in the root tip (Sola-Campoy et al. 2015). Ila et al. (2003) performed chromosome counts for P. vera, P. terebinthus, P. atlantica and P. eurycarpa. ...
The genus Pistacia L. consists of 11 or more tree and shrub species belonging to the Anacardiaceae family. Pistacia vera L. is the only commercially-important species within this genus with nuts large enough to be consumed. The center of diversity of P. vera is northern Iran, southern Turkmenistan and parts of Afghanistan. Botanically, pistachio fruits are semidry drupes composed of a fleshy exocarp and mesocarp (pericarp or hull), and a hard endocarp (shell) containing the edible kernel. Pistachio is a wind pollinated dioecious tree with apetalous pistillate and staminate inflorescences on separate female and male trees. Currently pistachio cultivation is expanding in Iran, the USA, Turkey, Greece, Italy, Spain, China, Tunisia and many other countries. However, its commercial production has been affected by the undesired physiological characteristics of alternate bearing, shell indehiscence, blank nuts and susceptibility to abiotic stresses, including drought and salinity, and fungal foliar and root diseases. Genetic improvement of these characteristics should be a factor in future breeding attempts to produce superior pistachio cultivars. This chapter describes the advances in traditional and molecular breeding of pistachio cultivars. The traditional breeding and hybridization programs discussed are focused on new female and male cultivars, and rootstocks, introduced through pistachio genomics and breeding programs. The discussion of germplasm biodiversity and molecular breeding summarizes the current knowledge of intra- and inter-specific genetic diversity, cytogenetic evaluations, and marker-assisted selection in the genus Pistacia. The current knowledge of pistachio genetic engineering including micropropagation, regeneration systems, somaclonal variation and genetic stability, in vitro conservation and cryopreservation, and genetic transformation studies are also discussed.
... Chromosome counting at the metaphase stage previously indicated that the pistachio genome has one very large pair of chromosomes (Ghaffari and Harandi 2002;Ila et al. 2003). Recently, Sola-Campoy et al. (2015) characterized the molecular cytogenetics of pistachio and found that the largest pair of chromosomes appears differentially condensed and heteropyknotic. ...
... We found the same results in this study, where all nine sex-linked SNP markers were heterozygous in females, supporting the hypothesis that this tree species has a ZW/ZZ sex determination system. Sola-Campoy et al. (2015) performed a molecular cytogenetic characterization study in pistachio which also supported the existence of a ZW/ZZ system. ...
... A region with suppressed recombination renders all genes within the same region as one locus, a fact that is supported in this study as well. Sola-Campoy et al. (2015) characterized pistachio chromosomes at the molecular cytogenetic level and indicated the largest chromosome pair (designated HC1) to be heteropyknotic and metacentric. This study positioned the sex locus of pistachio in the middle of the sex chromosome. ...
... Domestic pistachio is dioecious, and to bear fruit, both male and female parent plants need to be cultivated. Male and female plants conventionally go under asexual reproduction [20]. ...
... Domestic pistachio has 2n=30 chromosomes [1]. Pistachio's sexuality is determined using ZW system, and its female genotypes possess two distinct sex chromosomes, and hence they are considered heterogametic [20]. Genetic diversity estimation is one of the fundamental steps in genetic material preservation in gene banks and also in selective breeding programs [6]. ...
Precise investigation of genetic diversity by means of novel molecular tools has made it possible to identify the superior genotypes among various male and female pistachio populations. Cytogenetic studies have shed light on the possible presence of distinct sex chromosomes in male and female genotypes. In this study, 22 start codon targeted (SCoT) primers were used to investigate the genetic diversity of 22 male genotypes and 22 female cultivars of pistachio. A total of 434 loci were produced that 339 loci were polymorphism. The average value of polymorphic information content (PIC), marker index (MI), and resolving power (Rp), ranged from minimum 10, 0.5, and 1, to maximum 31, 11.40, and 17.86% subsequently. The genetic similarity between genotypes, were calculated using Jaccard's coefficient, ranged from 35 to 66%. The cluster analysis divided pistachio genotypes into six groups, and could efficiently differentiate the male and female genotypes. Analysis of molecular variance (AMOVA) classified the total diversity into intra-and inter-population diversities with a high genetic variation (92%) within populations. This study reveals that SCoT marker is a useful and valuable molecular tool to separate male and female pistachios and to determine the genetic diversity among the populations.
... The whole genus is dioecious, where male and female flowers are on independent trees [8]. However, few monoecious individuals of P. atlantica have also been noted [9]. ...
Pistacia genus belong to family Anacardiaceae and it is versatile in that its member species have food (P. vera), medicinal (P. lentiscus) and ornamental (P. chinensis) values. Various species of this genus have folkloric uses with credible mention in diverse pharmacopeia. As a trove of phenolic compounds, terpenoids, monoterpenes, flavonoids, alkaloids, saponins, fatty acids, and sterols, this genus has garnered pharmaceutical attention in recent times. With adequate clinical studies, this genus might be exploited for therapy of a multitude of inflammatory diseases, as promised by preliminary studies. In this regard, the ethnomedicinal, phytochemistry, biological potencies, risks, and scopes of Pistacia genus have been reviewed here.
... RAD-sequencing-based SNP detection allowed the identification of sex-linked SNP markers in Pistacia vera L. All markers were heterozygous in all female and homozygous in all male individuals tested, suggesting a ZW sex determination system (Kafkas et al. 2015; Table 1). The first molecular cytogenetic characterization of P. vera suggests the arrest of recombination in the largest heteropycnotic chromosome pair HC1 and confirms the presence of a ZW sex determination system (Sola-Campoy et al. 2015). ...
Key message: This review gives a comprehensive overview on the genomics of sex determination in dioecious
woody plants and plants with a tree-like habitus, in particular considering species where sex-linked regions
and/or markers have been identified.
Abstract: Dioecious plant species are characterized by unisexual flowers located on separate male or female individuals. While only about 5–6% of angiosperm species are reported to be dioecious, tree species seem to show a higher percentage of dioecy. Generally, it is presumed that various different genetic and developmental mechanisms underlie unisexuality in different dioecious species. This review focusses on the genomics of sex determination in dioecious woody plant species like trees, shrubs and vines as well as other plant species with a tree-like habitus like papaya and the monocot date palm. Findings for different tree species, including Diospyros lotus and members of the Salicaceae family, are summarized including information on sex-linked markers that enable to identify the sex of a tree before the tree reaches sexual maturity.
