ORIGINAL PAPER Cold-induced genetic instability in micropropagated Pistacia lentiscus L. plantlets I ˙ brahim Koc ¸ • Hu ¨ lya Akdemir • Ahmet Onay • Yelda O ¨ zden C ¸ iftc ¸i Received: 11 April 2014 / Revised: 29 April 2014 / Accepted: 2 June 2014 / Published online: 21 June 2014 Ó Franciszek Go ´rski Institute of Plant Physiology, Polish Academy of Sciences, Krako ´w 2014 Abstract Genetic stability of plants during in vitro propagation and conservation is one of the important aspects of plant biotechnology. In the present study, mi- cropropagated P. lentiscus L. shoot cultures, which are cultivated for the mastic resin, have been cold stored up to 12 months at 4 °C in the dark for different durations (2, 4, 6, 8, 10 and 12 months) and genetic alterations in cold storage conditions were evaluated. Growth parameters such as proliferation rate, shoot numbers per explant, shoot lengths and shoot forming capacity were also calculated. Since the highest proliferation rate (100 %) was obtained in 6 month-stored shoot cultures without any severe influence of cold stress on proliferation ability, amplified fragment length polymorphism (AFLP) and inter-retro- transposon amplified polymorphism (IRAP) marker sys- tems were used to determine genetic stability in the plantlets after this storage period. Totally, 702 scorable bands were produced by 10 AFLP primer pairs. Genetic similarity value of the non-stored (control) plant and cold- stored clones ranged from 0.66 to 0.84 with a mean of 0.74. In the case of IRAP, 159 bands were produced by 8 IRAP primers. Genetic similarity value of the non-stored plant and cold-stored clones varied from 0.65 to 0.83 and the average genetic similarity value was determined as 0.72. The genetic similarity indices revealed that genetic vari- ability was similar in both techniques. Our results showed that tissue culture and especially cold storage of P. len- tiscus L. may result transposons activation, thus could cause genetic instability. Keywords Pistacia lentiscus L. Á Cold stress Á Retrotransposon Á IRAP Á AFLP Introduction Pistacia lentiscus L. commonly known as mastic tree or lentisk is a natural evergreen species of Pistacia genus. It is widely distributed in Mediterranean region up to 600 m and over this altitude it is affected negatively by cold weather (Saidi et al. 2009). The cultivated tree of P. len- tiscus L. exclusively produces a valuable natural resin, which is generally known as Chios mastic gum. It is har- vested by wounding the trunk and thick branches (Acar 1988). The mastic gum production has mainly been per- formed in the Greek island of Chios for a long time as well as in Izmir, Turkey though not as much as in the island of Chios. In the past, the mastic gum was used as a traditional medicinal agent for treating hypertension, coughs, sore throats, eczema, stomach aches, kidney stones and jaundice (Gardeli et al. 2008; Palevitch and Yaniv 2000). In the present, the mastic has been commonly used as a flavor or supplement in foods, sweets, alcoholic beverages, chewing gum, toothpaste and lotions. Moreover, the essential oil of P. lentiscus L., composed of several active compounds (Castola et al. 2000), has some antimicrobial, antifungal, antibacterial and insecticidal effects (Barra et al. 2007; Lamiri et al. 2001). Thus, nowadays, this valuable resin possessing appreciable biological properties receives much Communicated by A. Krolicka. I ˙ . Koc ¸(&) Á H. Akdemir Á Y. O ¨ .C ¸ iftc ¸i Department of Molecular Biology and Genetics, Faculty of Science, Gebze Institute of Technology, 41400, Gebze Kocaeli, Turkey e-mail: koc_ibrahim@yahoo.com; ikoc@gyte.edu.tr A. Onay Department of Biology, Faculty of Science, Dicle University, Diyarbakır, Turkey 123 Acta Physiol Plant (2014) 36:2373–2384 DOI 10.1007/s11738-014-1610-0