Department of Horticulture

Random amplified polymorphic DNA (RAPD) markers were used to evaluate genetic stability of regenerants of cucumber plants obtained through somatic embryogenesis. Somatic embryo plants and plants of F1 hybrids, from which they were derived, were compared during weaning, early growth, flowering, fruiting and at maturity. No differences in phenotype were observed, by simple observation. Banding patterns were scored for the presence (+) or absence (-) of a DNA band, there were no visually detectable differences between the somatic embryo derived plants compared to their F1 parents in the Random Amplified Polymorphic DNA (RAPD) test using five primers OP-C10, OP-G14, OP-H05, OP-Y03 and OP-AT01. The results indicate the usefulness of RAPD markers to detect genetic instability in cucumber primary regenerant plants derived from somatic embryogenesis, and as a certification tool for monitoring genetic stability during the generation process.

Date palm is one of the most economically important woody crops cultivated in the Middle East and North Africa and is a good candidate for improving agricultural yields in arid environments. Nonetheless, long generation times (5-8 years) and dioecy (separate male and female trees) have complicated its cultivation and genetic analysis. To address these issues, we assembled a draft genome for a Khalas variety female date palm, the first publicly available resource of its type for a member of the order Arecales. The ~380 Mb sequence, spanning mainly gene-rich regions, includes >25,000 gene models and is predicted to cover ~90% of genes and ~60% of the genome. Sequencing of eight other cultivars, including females of the Deglet Noor and Medjool varieties and their backcrossed males, identified >3.5 million polymorphic sites, including >10,000 genic copy number variations. A small subset of these polymorphisms can distinguish multiple varieties. We identified a region of the genome linked to gender and found evidence that date palm employs an XY system of gender inheritance.

The combined role of carbohydrate and auxin is effective in root formation of date palm somatic embryos. The best combination resulted a mean of 2.5 roots per embryo and reached up to ten good and healthy roots when the rooting medium containing 60 g/l sucrose supplemented with NAA was used. 60 g/l sucrose combined with 0.4, 0.6 and 0.8 mg/l of either NAA or IBA gave about 74% root thickness. IBA with a low sucrose concentration of 30 g/l promoted root length, while NAA was found to be superior over IBA, when a high concentration of sucrose of 60 g/l was used which may be due to the effect of NAA is on the main root while IBA on the lateral root.

New primer pairs of genomic DNA microsatellite markers were tested to assess the genetic diversity of eleven date palm genotypes. The results indicated that out of thirty, only seven primers (23.3%) failed to amplify the expected PCR fragments, while thirteen primers (43.3%) amplified monomorphic banding patterns and the remaining ten primers (33.4%) generated polymorphic banding patterns. A total of 77 alleles have been observed with a mean of 7.7 alleles per locus. The average of gene diversity was 0.80 ranging from 0.6 (in marker DP168) to 0.9 (in two markers DP157 and DP175). These new co-dominant markers will be a starting point for researchers making use of the markers for genetic mapping and diversity analysis of date palm.

The role of cytokinine and auxin has been found to be effective in shoot multiplication of Ficus anastasia. When the multiplication medium contained 8 mgl -1 of BA with 1 mgl -1 of IBA, a mean of 20 lateral branches per stem was induced which was the best combination recorded. Even though IAA particularly combined with 2ip or kinetin, it had weak shoot multiplication influence resulting in only two lateral shoots which increased to 7 lateral shoots per stem when combined with BA. The plant height was negatively affected by the increase of cytokinin concentration. However, the control plant was more in length than any of the cytokinin treatments among combination with IBA or IAA.

Somatic embryogenesis of cucumber was affected by auxin and light during the induction phase. In the light, 2,4-dichlorophenoxyacetic acid (2,4-D) alone induced little embryogenesis, while combined with naphthaleneacetic acid (NAA) it induced 1.25 somatic embryos (SEs) per callus. In the dark 2,4-D alone induced 5 times more SEs per callus.

Whale sharks, Rhincodon typus, are known to aggregate to feed in a small number of locations in tropical and subtropical waters. Here we document a newly discovered major aggregation site for whale sharks within the Al Shaheen oil field, 90 km off the coast of Qatar in the Arabian Gulf. Whale sharks were observed between April and September, with peak numbers observed between May and August. Density estimates of up to 100 sharks within an area of 1 km 2 were recorded. Sharks ranged between four and eight metres' estimated total length (mean 6.9261.53 m). Most animals observed were actively feeding on surface zooplankton, consisting primarily of mackerel tuna, Euthynnus affinis, eggs. Citation: Robinson DP, Jaidah MY, Jabado RW, Lee-Brooks K, Nour El-Din NM, et al. (2013) Whale Sharks, Rhincodon typus, Aggregate around Offshore Platforms in Qatari Waters of the Arabian Gulf to Feed on Fish Spawn. PLoS ONE 8(3): e58255.

The massive destruction and deterioration of the habitat of Oryx leucoryx and illegal hunting have decimated Oryx populations significantly, and now these animals are almost extinct in the wild. Molecular analyses can significantly contribute to captive breeding and reintroduction strategies for the conservation of this endangered animal. A representative 32 identical sequences used for species identification through BOLD and GenBank/NCBI showed maximum homology 96.06% with O. dammah, which is a species of Oryx from Northern Africa, the next closest species 94.33% was O. gazella, the African antelope. DNA barcode sequences of the mitochondrial cytochrome C oxidase (COI) gene were determined for O. leucoryx; identification through BOLD could only recognize the genus correctly, whereas the species could not be identified. This was due to a lack of sequence data for O. leucoryx on BOLD. Similarly, BLAST analysis of the NCBI data base also revealed no COI sequence data for the genus Oryx.

Microsatellite markers containing simple sequence repeats (SSRs) are a valuable tool for genetic analysis. Our objective was to identify microsatellite markers that could be used to differentiate between male and female date palm (Phoenix dactylifera). The date palm is a dioecious plant whose sex cannot be determined until it reaches a reproductive age between 5 and 10 years. An early selection and/or differentiation of young seedlings into males and females could enhance breeding and assist research programs for genetic improvements of the date palm. Here, we report on the use of microsatellites for determining the sex of immature date palm. Using 14 microsatellite primer pairs with 129 date palm leaves and tissue culture samples from 34 cultivars which represent the major date palm diversity of Qatar, 254 microsatellite loci were detected, of these, 22 microsatellite loci could be used to identify 9 out of 12 male date palm samples (75%). The data also indicated that the heterozygous allele with the size 160/190 produced by the primer mPdCIR048 reoccurred 4 times exclusively in the 12 individual male samples but not in any of the 117 female date palm samples tested, and hence it is a promising candidate marker to detect male sex in date palm. Principal coordinate analysis (PCoA) of 12 male samples with 7 female Khasab cultivars produced 2 autonomous groups of males and females and similar results were observed with 13 female Shishi cultivars. Our results suggest that the SSR markers described here have potential in sex identification of date palm.

Diversity within and among the populations of Prosopis cineraria and Prosopis juliflora collected from different location of Qatar were explored using Inter Simple Sequence Repeat (ISSR) and Random Amplified Polymorphic DNA (RAPD) markers. A total of one hundred and nine bands were generated from twenty nine ISSR and nineteen bands from seven RAPD primers with an average polymorphism of more than ninety nine percent across all the genotypes. ISSR techniques were capable of distinguishing between P. cineraria and P. juliflora, through twenty one bands. However, of the seven RAPD markers, only three bands were able to distinguish between Prosopis species. The dendrograms for the analysis of genetic similarity show that the individuals from both species can be separated in two highly related groups. Our observations suggest that genetic variations among different accessions of Prosopis are identified using ISSR and RAPD analysis.

This study was conducted to examine the effect of glutamine and casein concentrations on callus growth and somatic embryogenesis of date palm (Phoenix dactylifera L.). Explant derived from offshoot tip was cultured on MS medium containing four different macro nutrients and different concentrations of casein and glutamine. The type and concentration of amino acid significantly affected the size and differentiation of date palm explant. As concentration increases the size and differentiation decreases up to 40% especially with casein, while 3gl -1 casein increase the callus weight up to 80g comparing with control which gave 20g.

Explants were taken from hypocotyls, cotyledons and leaves of five cucumber cultivars. The maximum callus weight in the induction medium was 1215.4 mg with the cv. Natica using hypocotyl explants and the minimum was 487.6 mg with cv. Mascot using leaf explants. When auxin was available in the induction phase somatic embryos were obtained; the absence of cytokinin caused a reduction in the number of embryos. The number of somatic embryos increased with sucrose concentration to a maximum of 9% sucrose. Three weeks on induction medium was needed for production of somatic embryos; prolonged incubation (6 weeks) gave poor somatic embryo numbers. As auxin concentration decreased in maturation medium somatic embryo yield increased; the highest number was obtained in the absence of auxin. Generally, the culture of callus on maturation medium in darkness was superior to 16 h light for somatic embryogenesis. Leaf explants of the cultivar Profito gave 37.3 embryos per replicate which was the highest number recorded. In addition, this cultivar yielded embryos in the shortest time period (6 weeks). Satisfactory somatic embryo numbers were obtained after three weeks on induction medium, plus three weeks on maturation medium, or four weeks on induction medium, plus two weeks on maturation medium, or five weeks on induction medium, plus one week on maturation medium. Comparison of characteristics of cucumber plants derived from somatic embryogenesis with those obtained from seed showed no significant difference in phenotype of plants, or fruits, or genotype (using RAPD DNA tests).

Date palm (Phoenix dactylifera) is the most important fruit tree in Qatar and is also used as an ornamental or shade plant in parks, gardens and alongside roads. Date palms are generally propagated by separating the offshoots produced by individual trees. Somaclonal variation refers to the phenotypic and genotypic variation observed in plants regenerated through cell culture. On the other hand, some somaclonal variations have desirable agronomic and commercial advantages and sometimes lead to the release of new cultivars. Inter-simple sequence repeat (ISSR) was used in this study to detect genetic variation based on DNA markers between the regenerated plantlet and its corresponding callus. Somaclonal variation between callus and more than one regenerated plant was observed in three cultivars: Kubkub, Merziban and Dharlag, respectively.

DNA of Qatari C. mydas samples were successfully sequenced using the Folmer forward and reverse primers. The identification with BOLD of approximately 688 base pairs sequence revealed maximum homology (99.84%) with C. mydas , which is a species of turtle has been declared "extinct in wild" by IUCN. The next closest species 93.79% , was N. depressa which has a restricted geographical distribution and was reported to be endemic to the Australian continental shelf. The finding of characteristic species-specific COI sequences offers the prospect of identifying marine turtle species by using DNA barcode methodology as an auxiliary tool for taxonomy. This can also be used during field work when identifying lost nests, animals stranded on beaches or those killed as part of catching in fishery nets. A further use is in forensic litigation when turtle eggs or meat are the only available material and for the development of Qatar gene bank information.

Plant propagation is the reproduction of new plants from seeds or vegetative parts , such as leaves, stems, or roots. The date palm is propagated easily by seeds and offsets, the propagation of date palms by offshoots was the commonly method of vegetative propagation used in date palm growing regions of the world to multiply up the best varieties. These offshoots are produced from axillary buds situated on the base of the trunk during the juvenile life of the palm. Offshoots develop slowly and the numbers of these are limited and are produced only within a certain period in the mother palm's life. Micropropagation is the production of whole plants from small sections such as a stem tip, node, meristem, embryo, or even a seed.

One of the most spectacular achievements in plant tissue culture has been the discovery of the induction of somatic embryogenesis in cell culture by which somatic cells develop into differentiated plants through characteristic embryological stages without fusion of gametes. These steps are accurately regulated by many factors, including plant genotype, level of sugar in the medium, type and concentration of growth regulators, photoperiod, gelling agents, time exposure and induction and maturation medium which stimulates somatic embryogenesis. This article reviews the recent work carried out on the role of various factors controlling somatic embryogenesis.