The genus Crocus, series Crocus (Iridaceae) in Turkey and 2 East Aegean islands: a genetic approach

Turkish Journal of Biology Turk J Biol (2014) 38: 48-62 © TÜBİTAK doi:10.3906/biy-1305-14 http://journals.tubitak.gov.tr/biology/ Research Article The genus Crocus, series Crocus (Iridaceae) in Turkey and 2 East Aegean islands: a genetic approach 1 2 3 4 5, 2 Osman EROL , Hilal Betül KAYA , Levent ŞIK , Metin TUNA , Levent CAN *, Muhammed Bahattin TANYOLAÇ 1 Department of Botany, Faculty of Science, İstanbul University, İstanbul, Turkey 2 Department of Bioengineering, Faculty of Engineering, Ege University, Bornova, İzmir, Turkey 3 Department of Biology, Faculty of Arts and Sciences, Celal Bayar University, Manisa, Turkey 4 Department of Field Crops, Faculty of Agriculture, Namık Kemal University, Tekirdağ, Turkey 5 Department of Biology, Faculty of Arts and Sciences, Namık Kemal University, Tekirdağ, Turkey Received: 06.05.2013 Accepted: 02.08.2013 Published Online: 02.01.2014 Printed: 24.01.2014 Abstract: In this study, a total of 26 Crocus specimens from different locations across Turkey and 2 East Aegean islands (Chios and Samos) were analyzed using 12 amplified fragment length polymorphism (AFLP) primer combinations to obtain information on genetic diversity, population structure, and genetic relationships. A total of 369 polymorphic AFLP bands were generated and scored as binary data. Genetic similarities were determined. Cluster analysis revealed 4 major groups among the 26 genotypes examined in this study. The nuclear DNA contents (2C) of the 26 Crocus specimens were found to range from 5.08 pg in C. asumaniae to 9.75 pg in C. sativus. Polymorphic information content (PIC) values were used to examine the capacity of the various primer pairs to amplify polymorphisms in the Crocus specimens. The PIC values ranged from 0.218 (M-CAA/E-AGC) to 0.512 (M-CAT/E-AAG) and showed an average of 0.34. In sum, we herein used AFLP analysis to identify a high level of polymorphism among Crocus specimens collected from various locations in Turkey and Greece, and our structural analysis yielded 2 reconstructed populations. These findings provide new insight into the relationships among different Crocus genotypes and show that AFLP analysis can be useful for Crocus diversity studies. Key words: Amplified fragment length polymorphism, Crocus, genetic diversity, genetic structure, nuclear DNA content 1. Introduction The genus Crocus L. belongs to the large family Iridaceae and is a systematically problematic genus. In the Old World, about 100 species (Harpke et al., 2013) are distributed between 10°W and 80°E and between 30°N and 50°N (Mathew, 1982). Phytogeographically, most Crocus species belong to the Mediterranean floristic region, with an additional range into the Irano-Turanian phytochorion. The species of this genus occur in climates characterized by a chilly or cold winter, rainy spring and autumn, and hot and dry summer. The developmental activity of the plant can be observed from autumn to spring; it survives the summer heat beneath the soil with its compact corm underground. Numerous species begin to grow their aerial parts during the autumn rains and flower afterwards. Some flower simultaneous with leaf growth or soon thereafter, while others flower in the spring when it is warmer. Based on the studies of Mathew (1982) and Mathew et al. (2009), the autumn-flowering Crocus sativus L., which produces the most expensive relict agricultural product in the world (saffron), was gathered with its relatives in the * Correspondence: 48 series Crocus (Table 1). That work was prepared according to morphological differences, as genetic tools were not commonly utilized back then. However, morphological characteristics can be affected by environmental factors acting during the developmental stages of the plant (Jonah et al., 2011), and the use of morphological characteristics in diversity studies could lead to misclassification (Joshi et al., 2011). Furthermore, numerous new taxa have been introduced in the botanical literature since the extensive work of Mathew (1982), and his subspecies system is no longer considered valid (Kerndorff and Pasche, 2011; Kerndorff et al., 2011). Molecular markers such as DNA (Lee, 1995) and isozymes (Winter and Kahl, 1995) are not affected by developmental processes or environmental influences and are used for determination of genetic diversity (Hamza et al., 2012; Poyraz et al., 2012; Sönmezoğlu et al., 2012; Taşkın et al., 2012; Türktaş et al., 2012; Zhang et al., 2012). They can be used to characterize organisms at the genomic level, yielding resolution that cannot be acquired by conventional systematic studies (Jonah et al., 2011). EROL et al. / Turk J Biol Table 1. Taxa belonging to series Crocus and their countries of distribution. Taxon Distribution (country) 1 Crocus asumaniae B.Mathew & T.Baytop Turkey 2 Crocus cartwrightianus Herb. Greece 3 Crocus sativus L. Spain, Greece, Italy, Morocco, Turkey, Iran, Pakistan 4 Crocus hadriaticus Herb. subsp. hadriaticus Greece 5 Crocus hadriaticus subsp. parnassicus (B.Mathew) B.Mathew Greece 6 Crocus hadriaticus subsp. parnonicus B.Mathew Greece 7 Crocus moabiticus Bornm. & Dinsm. ex Bornm. Jordan, Israel 8 Crocus mathewii Kernd. & Pasche Turkey 9 Crocus naqabensis Al-Eisawi Jordan, Israel 10 Crocus oreocreticus B.L.Burtt 11 Crocus pallasii Goldb. subsp. pallasii Greece Bulgaria, Romania, Macedonia, Ukraine, Greece, Turkey, Syria, Lebanon, Israel 12 Crocus pallasii subsp. dispathaceus (Bowles) B.Mathew 14 Crocus pallasii subsp. haussknechtii (Boiss. & Reut. ex Maw) B.Mathew Crocus pallasii subsp. turcicus B.Mathew 15 Crocus thomasii Ten. 13 As such, molecular markers are an effective method for obtaining information on genetic diversity and population structure (Odong et al., 2011). This can be extremely valuable to the preservation of wild species, as loss of genetic variability may reduce survival chances in the wild (Swanson, 1996). Studies on population genetics have attracted much attention because genetic diversity and variance are particularly important for the sustainability of species. Moreover, investigations of genetic diversity and population structure can provide important information for the management of genetic resources and the conservation of biodiversity in plants (Manel et al., 2003; Odong et al., 2011). In terms of methods, STRUCTURE is a Bayesian model-based algorithm that is widely used to cluster genetic data (Pritchard et al., 2000; Hubisz et al., 2009). For K ancestral populations, and assuming Hardy–Weinberg and linkage equilibrium within clusters, STRUCTURE estimates the allele frequencies in each cluster and the population membership for every individual (Pritchard et al., 2000). In the admixture model, it estimates admixture proportions for each individual and uses the Markov chain Monte Carlo approach to integrate the information over the parameter space and make cluster assignments (Pritchard et al., 2000). Alth (...truncated)