Genetic relationships of some Citrus genotypes based on the candidate iron chlorosis genes

Iron is one of the most important elements in plant mineral nutrition. Fe deficiency is a critical abiotic stress factor for Mediterranean citriculture; the development of marker-assisted selection for this trait would greatly enhance rootstock breeding. In this study, DNA sequencing and single-stranded conformation polymorphism (SSCP) analyses were performed to determine the allelic diversity of genes associated with tolerance to iron chlorosis in citrus. Two candidate iron chlorosis tolerance genes were selected from existing Citrus EST databases and Arabidopsis thaliana genome databases. Ferritin-3 chloroplast precursor and putative membrane transporter candidate gene sequences were used to define primers in conserved regions. Six citrus genotypes from the basic taxon of Citrus were used to identify polymorphic regions in the genes. Direct sequencing of the amplified DNA fragments from the candidate genes was performed, and single nucleotide polymorphisms (SNPs) and insertions/deletions (indels) were identified after sequence alignment. Based on the DNA sequencing analysis, a total of 6840 nucleotides of DNA were sequenced to identify SNPs and indels. In total, 263 SNPs and 15 indels were identified for both genes. We detected 38.45 SNPs and 2.19 indels for each 1000 b on average from the DNA sequencing results. New primers were designed in conserved areas flanking polymorphic ones for SSCP analysis. SSCP-PCR analysis was performed with 25 citrus genotypes. The neighbor-joining method was used for cluster analysis. Trifoliate genotypes and their hybrids (known to be sensitive to iron chlorosis) clustered together, whereas genotypes tolerant to iron chlorosis were more spread out on the dendrogram. Mandarins also showed high diversity for both genes according to SSCP results. Differences were found among sour orange genotypes known to have differential tolerance behavior to iron chlorosis. (Résumé d'auteur

Genetic Transformation in Citrus

Citrus is one of the world’s 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

A reference genetic map of C. clementina hort. ex Tan.; citrus evolution inferences from comparative mapping

Background: Most modern citrus cultivars have an interspecific origin. As a foundational step towards deciphering the interspecific genome structures, a reference whole genome sequence was produced by the International Citrus Genome Consortium from a haploid derived from Clementine mandarin. The availability of a saturated genetic map of Clementine was identified as an essential prerequisite to assist the whole genome sequence assembly. Clementine is believed to be a 'Mediterranean' mandarin x sweet orange hybrid, and sweet orange likely arose from interspecific hybridizations between mandarin and pummelo gene pools. The primary goals of the present study were to establish a Clementine reference map using codominant markers, and to perform comparative mapping of pummelo, sweet orange, and Clementine. Results: Five parental genetic maps were established from three segregating populations, which were genotyped with Single Nucleotide Polymorphism (SNP), Simple Sequence Repeats (SSR) and Insertion-Deletion (Indel) markers. An initial medium density reference map (961 markers for 1084.1 cM) of the Clementine was established by combining male and female Clementine segregation data. This Clementine map was compared with two pummelo maps and a sweet orange map. The linear order of markers was highly conserved in the different species. However, significant differences in map size were observed, which suggests a variation in the recombination rates. Skewed segregations were much higher in the male than female Clementine mapping data. The mapping data confirmed that Clementine arose from hybridization between 'Mediterranean' mandarin and sweet orange. The results identified nine recombination break points for the sweet orange gamete that contributed to the Clementine genome. Conclusions: A reference genetic map of citrus, used to facilitate the chromosome assembly of the first citrus reference genome sequence, was established. The high conservation of marker order observed at the interspecific level should allow reasonable inferences of most citrus genome sequences by mapping next-generation sequencing (NGS) data in the reference genome sequence. The genome of the haploid Clementine used to establish the citrus reference genome sequence appears to have been inherited primarily from the 'Mediterranean' mandarin. The high frequency of skewed allelic segregations in the male Clementine data underline the probable extent of deviation from Mendelian segregation for characters controlled by heterozygous loci in male parents

Discovery of mutations with TILLING and ECOTILLING in plant genomes

TILLING (Targeting Induced Local Lesions IN Genomes) and ECOTILLING are methods used in detecting induced or naturally occurring mutations in many species. High-throughput TILLING allows the rapid, easy and cost-effective discovery of induced point mutations in populations of chemically mutagenized individuals. The use of the TILLING technique to survey natural variation in genes is called ECOTILLING. TILLING and ECOTILLING have recently been used for the detection of both induced mutation and natural DNA polymorphism. In this review, we illustrate how TILLING and ECOTILLING methods can be employed for discovering mutations

Effects of different media on micropropagation and rooting of myrtle (Myrtus communis L.) in in vitro conditions

European Biotechnology Congress -- MAY 25-27, 2017 -- Dubrovnik, CROATIAWOS: 000413585400356

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

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

WOS: 000379533500016PubMed ID: 27193591Snake 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.Scientific Research Projects Coordination Unit of Cukurova UniversityCukurova University [FBA-2014-2380]This research was supported by the Scientific Research Projects Coordination Unit of Cukurova University (FBA-2014-2380). The authors are grateful to Dr. Aydin Uzun for his kindly help in the PIC analysis; AARI, TAEA, EMTZARI, INRA (Michel Pitrat), and Veysel Aras for seed supplying

Molecular Characterization of Turkish Cactus Pear (& IT;Opuntia & IT;spp.) by RAPD Markers

Opuntia ficus-indica Mill. commonly known as cactus pear is the most agronomically important species in Cactaceae. Turkey has important genetic resources of Opuntia spp. which should be characterized for further breeding strategies. In this study, molecular characterization of plant materials collected from different regions of Turkey in which Opuntia species grown naturally, was performed by using Random Amplified Polymorphic DNA (RAPD) markers. DNA was successfully amplified by 50 RAPD primers. Among 250 bands generated by the RAPD primers, 180 were polymorphic. The number of bands detected by a single primer set ranged from one to 12 (average of five bands/primer). The percentage of polymorphism was 72% based on RAPD data. All data were scored as discrete characters and unweighted pair group method with arithmetic mean (UPGMA) dendrogram and principle coordinate analysis (PCoA) were performed. Based on the results, Opuntia genotypes showed high genetic diversity and we showed that RAPD markers are powerful tool to discriminate Turkish Opuntia genotypes. The high genetic diversity existing in the Turkish germplasm suggests that it would be beneficial to utilize this pool in Opuntia breeding programs and germplasm management activities