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    Homoploid hybrids of Origanum (Lamiaceae) in Turkey: morphological and molecular evidence for a new hybrid
    (Taylor & Francis Ltd, 2021) Arabaci, Turan; Celenk, Sevcan; Ozcan, Taner; Martin, Esra; Yazici, Turker; Acar, Mikail; Uzel, Devrim
    In this study, three hybrids of Origanum (Lamiaceae) were examined in detail using morphological, karyological, palynological and molecular approaches. One of the three hybrids, O. x aytacii, is here described for the first time, and is compared with its putative parents, O. sipyleum and O. vulgare subsp. hirtum. In addition to morphological, karyological and palynological features, we also examined nuclear ribosomal DNA (ITS) sequences of O. x intermedium (O. onites x O. sipyleum), O. x intercedens (O. onites x O. vulgare subsp. hirtum) and their purported parental species that share the same area with the new hybrid. Pollen grains were hexacolpate and isopolar. The range of Polar/Equatorial ratio (P/E) of pollen for investigated taxa varied from 0.74 to 0.99. All investigated taxa are diploid with a chromosome number as 2n = 30. According to molecular results, O. x aytacii was the most polymorphic taxon. In addition, DNA sequences showed that O. x intercedens was more similar to O. vulgare subsp. hirtum than to O. onites, and O. x intermedium was more similar to O. onites than to O. sipyleum. Furthermore, O. onites and O. vulgare subsp. hirtum have many different ITS haplotypes, probably resulting from backcrossing with different individuals. Results obtained in this study demonstrate that hybridization has played a major role in the process of Origanum speciation.
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    Hybridization among three Cirsium (Asteraceae) species and important evidence for three new hybrids from Turkey
    (Tubitak Scientific & Technological Research Council Turkey, 2019) Dirmenci, Tuncay; Ozcan, Taner; Arabaci, Turan; Celenk, Sevcan; Ismailova, Gulnar; Yildiz, Bayram
    In this study, three new hybrids from the genus Cirsium are described for the first time. Cirsium xnezaketiae Yildiz, Dirmenci & Arabaci, C. xkelkitensis Yildiz, Arabaci & Dirmenci, and C. xerzincanicum Yildiz, Dirmenci & Arabaci are investigated in detail morphologically, palynologically, and molecularly. The hybrid individuals were detected on field trips due to their intermediate morphological characters. Their morphological properties were analyzed to compare with their parents. The pollen grain morphologies of the hybrids and their allies were investigated using light and a scanning electron microscope. The pollen grains were radially symmetrical, isopolar, trizonocolporate, and with echinate or scabrate sculpturing. The tectum is psilate/punctate, microreticulate, or ornate in sculpture. Dimorphic pollen grains were encountered in C. leucocephalum (Willd.) Spreng. subsp. leucocephalum. Two nuclear DNA regions were used to find single nucleotide polymorphisms. nrITS DNA data gave more information than nrETS data about polymorphism. In conclusion, C. xnezaketiae, C. xkelkitensis, and C. xerzincanicum exhibit some significant morphological, palynological, and molecular differences from their parents and present evidence of potential introgression hybridization. Since the hybrids live in a complex with their parents, and some parents have polymorphic loci like their putative hybrids, it can be presented as evidence for potential introgression since backcrossing may be possible among taxa.
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    An important hybrid zone: evidence for two natural homoploid hybrids among three Origanum species
    (Finnish Zoological Botanical Publishing Board, 2020) Dirmenci, Tuncay; Ozcan, Taner; Yazici, Turker; Arabaci, Turan; Celenk, Sevcan; Martin, Esra
    Based on combined results of different approaches we describe two new natural hybrids, Origanum x bilgilii Dirmenci, T. Yazici & Arabaci and O. x dumanii Dirmenci, Arabaci & T. Yazici from southern Turkey (Antalya). They have a common parent, Origanum saccatum. Morphology and pollen micromorphology of the collected plants were studied, and a comparison of one nuclear (nrITS) and one chloroplast (rpl32) DNA marker was performed. The ploidy level of the two hybrids was established by chromosome counts. Both hybrids have some morphological characters in the leaves. bracts, calyces and corollas that are intermediate between those of their parents. Surface sculpturing and pollen grain size and shape of the hybrids vary and differ to a certain degree from those of the parental species. Heterozygous loci were detected in nrITS sequences of both O. x bilgilii and O. x dumanii, while rpl32 sequences were uninformative. Both hybrids and their parents have the same chromosome number of 2n = 30.
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    Karyotype studies on the genus Origanum L. (Lamiaceae) species and some hybrids defining homoploidy
    (Firenze Univ Press, 2020) Martin, Esra; Dirmenci, Tuncay; Arabaci, Turan; Yazici, Turker; Ozcan, Taner
    In this study, chromosome numbers and structures of some Origanum L. taxa growing in Turkey were identified. Using the Image Analysis System, the complements of plant accessions belonging to eight sections, namely Amaracus (Gleditsch) Vogel, Anatolicon Benth., Brevifilamentum Ietsw., Longitubus Ietsw., Chilocalyx (Briq.) Ietsw., Majorana (Miller) Ietsw., Origanum, and Prolaticorolla Ietsw. were determined, by classification with the cytogenetic method. The chromosome number of all taxa except O. sipyleum L. (2n = 28) and O. rotundifolium Boiss. (2n = 28) is 2n = 30. In addition, the hybrids and their parental species have 2n = 30 chromosome numbers. Also, the smallest chromosome length is 0.32 mu m in O. sipyleum. The largest chromosome length is 2.02 mu m in O. minutiflorum O.Schwarz & P.H.Davis. The smallest total haploid length is 10.08 mu m in O. vulgare subsp. hirtum (Link) A.Terracc. and the largest value is 22.00 mu m in O. haussknechtii Boiss. The smallest mean length is 0.33 mu m in O. vulgare L. subsp. hirtum and O. saccatum P.H.Davis. The largest mean length is 0.74 mu m in O. sipyleum L. The chromosome numbers obtained in this study support the speciation of Origanum members via homoploid hybridization. Finally, the somatic chromosome numbers of 10 taxa (including 2 hybrids), chromosome measurements of 22 taxa (including 2 hybrids), and ideograms of 19 taxa (including 2 hybrids) were for the first time performed in this study.
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    Mericarp morphology of the genus Origanum (Lamiaceae) and its taxonomic, significance in Turkey
    (Magnolia Press, 2020) Ecevit-Genc, Gulay; Ozcan, Taner; Dirmenci, Tuncay; Arabaci, Turan
    Origanum is a well-known genus that is widely distributed and comprises many hybrids and endemic species in Turkey. Some morphological and molecular studies in the literature have aimed to clarify infrageneric or sectional classification of the genus. However, studies regarding the shape, size, and color of mericarps of Origanum taxa remain limited. The mericarp micromorphology of 30 taxa, including 7 hybrids of the genus Origanum, were evaluated herein using both stereo microscopy and scanning electron microscopy (SEM) to determine some useful features for taxonomical classification of the genus. The shapes of mericarps are usually ellipsoid, rarely ellipsoid-oblong, obovoid, broadly obovoid, while the color of mericarps vary from shades of brown to reddish. A significant variation was observed in the surface ornamentation of mericarps, which was mainly useful at the sectional and species level. Also determined were 2 main types: I and II, and 5 subtypes: pusticulate, reticulate-ruminate, reticulate-foveate, ruminate, and foveate. The micromorphological characters of mericarps, in addition to their morphological features, will contribute taxonomically to the classification of the sections of the genus Origanum and separation of the species within the sections. In addition, these characters will be useful to understand the effect of hybridization on variations in the micromorphological characters. This was the first detailed study on the mericarp micromorphology of the genus Origanum and its taxonomic implications.
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    Morphological, cytological, palynological and molecular evidence on two new hybrids from Turkey: an example of homoploid hybridization in Origanum (Lamiaceae)
    (Magnolia Press, 2018) Dirmenci, Tuncay; Ozcan, Taner; Yazici, Turker; Arabaci, Turan; Martin, Esra
    Two new hybrids of Origanum, O. x malyeri and O. x sevcaniae, are described and illustrated in detail. The general morphology, pollen and chromosome features, and nuclear (ITS) and chloroplast (rp132) genomes of collected specimens were studied. Origanum xmalyeri is a hybrid between O. boissieri and O. vulgare subsp. hirtum and O. xsevcaniae is another hybrid between O. vulgare subsp. hirtum and O. vogelii. These two new hybrids have some morphological intermediate characters between their parents. The pollen morphology of O. xsevcaniae and its parents were studied and documented in detail using light microscopy (LM) and scanning electron microscopy (SEM). O. xsevcaniae pollen is small to medium (P=18.49-21.03 mu m, E=22.20-26.63 mu m), suboblate (73%) to oblate (22%), the range of P/E ratio is from 0.73 to 0.85. Pollen grains are hexacolpate with granular membranes. Pollen grains were identified as bireticulate exine ornamentation with scanning electron microscopy examinations. The somatic chromosome number of O. boissieri, O. vulgare subsp. hirtum, O. vogelii, and O. x sevcaniae were counted as 2n = 30. Pollen characters and somatic chromosome numbers of O. x malyeri could not be examined because it has only female flowers and has not any nutlets. Also, according to molecular results, O. xmalyeri and O. x sevcaniae have some polymorphic nucleotide regions in their nuclear ITS genomes and which means they have two different DNA dataset belonging to their parents. Also, some individuals of O. x sevcaniae parents have single nucleotide polymorphism, too. These individuals live together with their hybrids and hybridization is probably a continuing process in that hybrid swarms. These present results support previous reports for the speciation of Origanum members via hybridization.
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    A rearranged homoploid hybrid species of Origanum (Lamiaceae): O. xmunzurense Kit Tan & Sorger
    (Taylor & Francis Ltd, 2019) Dirmenci, Tuncay; Ozcan, Taner; Acar, Mikail; Arabaci, Turan; Yazici, Turker; Martin, Esra
    Origanum munzurense Kit Tan & Sorger (Sect. Brevifilamentum Ietsw.) was described by Kit Tan & Sorger in 1984, and it is an accepted species related to O. acutidens (Hand.-Mazz.) Ietsw. belonging to sect. Brevifilamentum. It is morphologically intermediate between O. acutidens and O. vulgare L. subsp. gracile (K.Koch) Ietsw., and its type locality lies in the overlap zone between the geographic distributions of these two taxa. We hypothesized that O. munzurense is in fact a hybrid between the two aforementioned taxa and we tested this hypothesis with the general morphology, chromosome features, and nuclear (ITS1-ITS2) and chloroplast (rpl32) DNA sequences of specimens of O. munzurense and its putative parental species, O. vulgare subsp. gracile and O. acutidens. The somatic chromosome number of O. munzurense, O. vulgare subsp. gracile and O. acutidens were counted as 2n=30. Origanum munzurense presented polymorphic sites in the nuclear ITS region, but the chloroplast markers did not allow us to identify the putative maternal of O. munzurense. Our results suggest that O. munzurense is indeed a hybrid, and its rearrangement as a new homoploid hybrid (O. xmunzurense) would be more accurate. These present results support previous reports for the speciation of Origanum members via hybridization.