Responses of three tomato cultivars to sea water salinity 1. Effect of salinity on the seedling growth

The effect of sea water salinity (1500, 2500 and 3500 ppm) on the growth of tomato (Lycopersicon esculentum) cultivars (Trust, Grace and Plitz) was studied. The sea water salinity delayed seed germination and reduced germination percentage especially with increasing salinity level. Chlorophyllb content was higher than chlorophyll a, and both of them decreased with increasing salinity. The seedling height increased with time but decreased with increasing salinity in all cultivars. Seedlings fresh and dry shoot and root weights were decreased with increasing salinity. The growth of stem, leave and root after over 80 days of exposure to sea water salinity was affected by sea water dilution especially those of trust and grace cultivars. The grace cultivar was less affected by sea water salinity on the germination stage, while the plitz cultivar has good tolerant to sea water salinity for prolonged perio

Cryopreservation of Embryogenic Callus of Date Palm (Phoenix dactylifera) cv. Magdoul through Encapsulation-Dehydration Technology

To overcome the genetic deterioration and the extinction of date palm genotypes and species as result of environmental challenges, it has become necessary to develop techniques that allow the remaining genetic resources to be persevered under in-vitro conditions for long period without a substantial decline in the vitality, genetic stability and low survival. The development of an effective cryopreservation method for date palm (cv. Magdoul) via an encapsulation-dehydration method for long term conservation was researched in this study. Embryogenic callus, obtained from shoot tip culture, was used as explants and exposed to different concentration of sucrose (0.0, 0.5, 0.75, 1.0 and 1.5 M) combined with dehydration time (0–10 days) and different drying time (1–10 h). It was found that using sucrose at 0.75 M was more effective compared with using 1.0 and 1.5 M. Among the drying time tested, 4 h gave the best result for survival. The interaction treatment between sucrose, dehydration and moisture content (MC) was studies. After different periods of time in liquid nitrogen, the greatest values of survival (74.4%) and regrowth (71.25%) after 6 weeks of storage were obtained when 0.75 M sucrose for three days followed by 4 h dehydration period with a 39.50% MC was applied. The present results indicated that encapsulation-dehydration can be applied as a simple and effective protocol to a diverse range of cv. Magdoul genetic resources using embryogenic calli. © 2020 Friends Science Publisher

One fungus, which genes?: development and assessment of universal primers for potential secondary fungal DNA barcodes

The aim of this study was to assess potential candidate gene regions and corresponding universal primer pairs as secondary DNA barcodes for the fungal kingdom, additional to ITS rDNA as primary barcode. Amplification efficiencies of 14 (partially) universal primer pairs targeting eight genetic markers were tested across > 1 500 species (1 931 strains or specimens) and the outcomes of almost twenty thousand (19 577) polymerase chain reactions were evaluated. We tested several well-known primer pairs that amplify: i) sections of the nuclear ribosomal RNA gene large subunit (D1-D2 domains of 26/28S); ii) the complete internal transcribed spacer region (ITS1/2); iii) partial beta-tubulin II (TUB2); iv) gamma-actin (ACT); v) translation elongation factor 1-alpha (TEF1 alpha); and vi) the second largest subunit of RNA-polymerase II (partial RPB2, section 5-6). Their PCR efficiencies were compared with novel candidate primers corresponding to: i) the fungal-specific translation elongation factor 3 (TEF3); ii) a small ribosomal protein necessary for t-RNA docking; iii) the 60S L10 (L1) RP; iv) DNA topoisomerase I (TOPI); v) phosphoglycerate kinase (PGK); vi) hypothetical protein LNS2; and vii) alternative sections of TEF1 alpha. Results showed that several gene sections are accessible to universal primers (or primers universal for phyla) yielding a single PCR-product. Barcode gap and multi-dimensional scaling analyses revealed that some of the tested candidate markers have universal properties providing adequate infra- and inter-specific variation that make them attractive barcodes for species identification. Among these gene sections, a novel high fidelity primer pair for TEF1 alpha, already widely used as a phylogenetic marker in mycology, has potential as a supplementary DNA barcode with superior resolution to ITS. Both TOPI and PGK show promise for the Ascomycota, while TOPI and LNS2 are attractive for the Pucciniomycotina, for which universal primers for ribosomal subunits often fail

Metagenomic analysis of fungal taxa inhabiting Mecca region, Saudi Arabia

AbstractThe data presented contains the sequences of fungal Internal Transcribed Spacer (ITS) and 18S rRNA gene from a metagenome of the Mecca region, Saudi Arabia. Sequences were amplified using fungal specific primers, which amplified the amplicon aligned between the 18S and 28S rRNA genes. A total of 460 fungal species belonging to 133 genera, 58 families, 33 orders, 13 classes and 4 phyla were identified in four contrasting locations. The raw sequencing data used to perform this analysis along with FASTQ file are located in the NCBI Sequence Read Archive (SRA) under accession numbers: SRR3150823, SRR3144873, SRR3150825 and SRR3150846

Micropropagation of virus-free plants of Saudi fig (Ficus carica L.) and their identification through enzyme-linked immunosorbent assay methods

© 2018, The Society for In Vitro Biology. Viral infection is one of the most serious biotic stresses, which disturbs the growth and productivity of many horticultural crops, including that of fig (Ficus carica L.). The production of plants free of viruses, such as fig mosaic virus (FMV), has become a priority in many plant breeding programs. In this study, leaves from plants of two fig cultivars, Kodato and Dattora, infected with FMV were collected from both Mecca and Al-Taif, Saudi Arabia. Transmission electron microscopy of ultrathin leaf sections showed double membrane bodies, characteristic of FMV particles, only in the mesophyll cells of infected samples. Protein analysis using sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of a protein band with a molecular weight of 35 kDa, which corresponded to the viral coat protein; and FMV was confirmed by Western blot and enzyme-linked immunosorbent assay (ELISA) tests. To obtain virus-free plants, apical shoot culture was applied. A comparison of various artificial media with different concentrations of growth regulators was evaluated to optimize shoot formation, shoot multiplication, and root formation, and was followed by plant acclimation ex vitro. Direct ELISA analysis of shoots micropropagated from meristem tip explants indicated that there were virus-free shoots, when compared to infected plants (positive control), while there were no significant differences between these explants and healthy samples (negative control). This study demonstrated that in vitro micropropagation of Saudi F. carica infected with FMV virus led to the successful elimination of the virus

Humic-like bioactivity on emergence and early growth of maize (Zea mays L.) of water-soluble lignins isolated from biomass for energy

Lignin of lignocellulosic residues from biomass for energy can be exploited in sustainable agriculture as plant stimulants. Lignin monomers or their microbial bioproducts are mainly responsible for the plant growth promotion exerted by humic matter in soil. The aim of this work was to verify the humic-like bioactivity of water-soluble lignin isolated from biomass for energy towards plant growth and relate the biostimulation to the lignin molecular structure. Two water-soluble lignins isolated from giant reed (AD) and miscanthus (MG) were characterized for molecular composition by H-1 and P-31 1D-, C-13-H-1 2D-, DOSY-NMR spectroscopy and for conformational structure by size-exclusion chromatography. The effect of different aqueous concentrations of lignin on germination of maize seeds and growth of maize plantlets was assessed in growth-chamber experiments. Both lignins showed humic-like supramolecular structures, but different conformational stability and molecular composition. Their largest bioactivity was revealed at 10 and 50 ppm of lignin organic carbon and both significantly increased length of radicles, lateral seminal roots, and coleoptiles of maize seedlings, as well as total shoot and root dry weights and root length of maize plantlets. However, differences in AD and MG bioactivity were attributed to their conformational stabilities and content of amphiphilic molecules, which may control both the adhesion to plant roots and the release of bioactive molecules upon interactions with plant-exuded organic acids. The humic-like bioactivity of water-soluble lignins indicated that lignocellulosic residues from energy crops may be profitably recycled in agriculture as effective plant growth promoters, thereby increasing the economic and environmental sustainability of energy production from non-food biomasses