Ozhan Simsek

Genetic Transformation in Citrus

Citrus is one of the worlds important fruit crops. Recently, citrus molecular genetics and biotechnology work have been accelerated in the world. Genetic transformation, a biotechnological tool, allows the release of improved cultivars with desirable characteristics in a shorter period of time and therefore may be useful in citrus breeding programs. Citrus transformation has now been achieved in a number of laboratories by various methods. Agrobacterium tumefaciens is used mainly in citrus transformation studies. Particle bombardment, electroporation, A. rhizogenes, and a new method called RNA interference are used in citrus transformation studies in addition to A. tumefaciens. In this review, we illustrate how different gene transformation methods can be employed in different citrus species.

Genetic Characterization of Turkish Snake Melon (Cucumis melo L. subsp. melo flexuosus Group) Accessions Revealed by SSR Markers

Snake melon is an important cucurbit crop especially in the Southeastern and the Mediterranean region of Turkey. It is consumed as fresh or pickled. The production is mainly done with the local landraces in the country. Turkey is one of the secondary diversification centers of melon and possesses valuable genetic resources which have different morphological characteristics in case of snake melon. Genetic diversity of snake melon genotypes collected from different regions of Turkey and reference genotypes obtained from World Melon Gene Bank in Avignon-France was examined using 13 simple sequence repeat (SSR) markers. A total of 69 alleles were detected, with an average of 5.31 alleles per locus. The polymorphism information content of SSR markers ranged from 0.19 to 0.57 (average 0.38). Based on cluster analysis, two major groups were defined. The first major group included only one accession (61), while the rest of all accessions grouped in the second major group and separated into different sub-clusters. Based on SSR markers, cluster analysis indicated that considerably high genetic variability exists among the examined accessions; however, Turkish snake melon accessions were grouped together with the reference snake melon accessions.

Erratum to: Molecular Characterization of Cyclamen Species Collected from Different Parts of Turkey by RAPD and SRAP Markers.

The genus Cyclamen (family Myrsinaceae) contains about 20 species, most of which occur in the Mediterranean region. Turkey has critically important Cyclamen genetic resources. Molecular characterization of plant materials collected from different regions of Turkey in which Cyclamen species grow naturally, namely Adana, Antalya, Aydin, Mugla, Izmir, Denizli, Kahramanmaras, Osmaniye, Eskisehir, Trabzon, and Rize provinces, was performed using RAPD and SRAP markers. DNA was successfully amplified by 30 RAPD primers and 14 SRAP primer pairs. Among the 470 bands generated by the RAPD primers, 467 were polymorphic. The number of bands detected by a single primer set ranged from 11 to 22 (average of 15.6). The percentage polymorphism was 99.3 % based on the RAPD data. In the SRAP analysis, a total of 216 bands were generated, showing 100 % polymorphism. The number of bands detected by a single primer set ranged from 9 to 22 (average of 15.4). All data were scored and UPGMA dendrograms were constructed with similar results in both marker systems, i.e., different species from nine provinces of Turkey were separated from each other in the dendrograms with the same species being clustered together.

An Overview of In Vitro Haploid Plant Production in Citrus

The main objectives of Citrus breeding are to have new varieties with a shorter juvenile non-fruiting period, an increased yield, a longer ripening season, regular fruit bearing, seedlessness and improved external and internal quality of the fruits. To make available new scions and rootstocks selected for resistance or tolerance to biotic and abiotic stresses is another important aim in Citrus improvement. Citrus breeding is based either on conventional methods (hybridization, selection, mutation) or biotechnological methods employing in vitro tissue culture, regeneration from protoplasts, somatic hybridization, in vitro mutant selection, genetic transformation and haploid production. An integrated approach between innovative and conventional tools is fundamental to obtaining large improvements in a short time. Haploid plants have some advantages for the plant breeding because of their one set of chromosomes, identified recessive mutations and reducing the breeding time. There are several methods to produce haploid plants such as androgenesis and gynogenesis. The pollen and microsphore cultures are used for androgenesis. The ovule and ovary culture are used for the gynogenesis. In this review we describe the principals of the haploid plant cultures and we illustrated some haploid studies in citrus.

Determination of genes involved in lignification of pomegranate seeds by transcriptome sequencing

The lower convective layer (LCL) of the Atlantis II (ATII) brine pool of the red sea is a unique environment characterized by high salinity of around 4 Molar, temperature of 68οC, and very high concentrations of heavy metals. We have previously described a metagenome-derived mercuric reductase, ATII-LCL MerA, from the LCL of the ATII brine pool that is thermo-stable at 60oC and retain more than 70% of its activity after 10 minutes incubation at 70oC. One of the structural characteristics of this enzyme, that distinguish it from a thermosensitive ortholog, is the limited substitutions of amino acids, less than 9%, including the presence of 4 aspartic acids at positions 414 to 417 replacing 4 alanine in the thermo-sensitive MerA. In this work, we identified a metagenome-derived MerA from the ATII-LCL environment, ATII-LCL-NH, that is lacking all the substitutions observed in ATII-LCL MerA. Site-directed mutagenesis