Search Results (5)

Halophyte plants, with genes responsive to abiotic stress, are promising candidates to enhance crop stress tolerance, but reliable RT-qPCR analysis requires the precise selection of candidate reference genes (CRGs) due to their inconsistent expression across tissues and stress conditions. In this study eight CRGs of A. littoralis, AlEF1A, AlRPS3, AlGTFC, AlRPS12, AlUBQ2, AlTUB6, AlACT7, and AlGAPDH1, were analyzed to assess their stability for the normalization of RT-qPCR data under polyethylene glycol (PEG, 20% w/v for drought simulation), abscisic acid (ABA, 100 μM), and cold stress (4 °C) treatments. The result of the algorithms suggested different CRGs for different treatments or tissue types. However the comprehensive analysis indicates that AlEF1A is the most stable CRG for PEG-treated leaf tissue, but AlTUB6 is preferable for PEG-treated root tissue, while for PEG-treated leaf and root tissues, AlEF1A can be suggested. For cold-stressed leaf and/or root samples, AlRPS3 was the most stable. For ABA-treated leaf and root tissues, AlGTFC and AlEF1A were the most stable CRGs, respectively, whereas AlTUB6 was suggested for ABA-treated leaf and root tissues. Collectively, for all stresses combined (PEG, ABA, and cold), AlGTFC was the most stable CRG in leaf samples, while AlRPS3 was the most stable in root samples and combined leaf and root samples. The validation analysis indicates a statistically significant difference (p value < 0.05) between normalization with the most and least stable CRGs. This research suggests reliable tissue-specific RGs for A. littoralis under abiotic stresses that can enhances the accuracy of gene expression quantification. Full article

Plants have acquired sets of highly regulated and complex signaling pathways to respond to unfavorable environmental conditions during evolution. Calcium signaling, as a vital mechanism, enables plants to respond to external stimuli, including abiotic and biotic stresses, and coordinate the basic processes of growth and development. In the present study, two calcium sensor families, CBL and CIPK, were investigated in a halophyte plant, Aeluropus littoralis, with a comprehensive analysis. Here, six AlCBL genes, and twenty AlCIPK genes were studied. The analysis of the gene structure and conserved motifs, as well as physicochemical properties, showed that these genes are highly conserved during evolution. The expression levels of AlCBL genes and AlCIPK genes were evaluated under salt stress in leaf and root tissue. Based on the real-time RT-PCR results, the AlCIPK gene family had a higher variation in mRNA abundance than the AlCBL gene family. AlCIPK genes were found to have a higher abundance in leaves than in roots. The results suggest that the correlation between AlCBL genes and AlCIPK is tissue-specific, and different correlations can be expected in leaves and roots. Based on these correlations, AlCIPK3.1–AlCBL4.1 and AlCIPK1.2–AlCBL4.4 can be co-expressed in the root tissue, while AlCBL10 has the potential to be co-expressed with AlCIPK5, AlCIPK26, and AlCIPK12.3 in the leaf tissue. Our findings reveal valuable information on the structure and function of calcium sensor families in A. littoralis, a halophyte plant, that can be used in future research on the biological function of CBLs and CIPKs on salt stress resistance. Full article

The arid climate of the Saharan regions is accentuated even more by the consequences of climate change and environmental threats, thus affecting normal plant development. The salinization of soils is one of the major stresses in the Moroccan Sahara Desert that strongly penalizes the production. In this sense, it would be interesting to explore the native flora of the target regions, and using it remains the best option to provide sustainable agriculture. The present study is part of a collaborative project with the aim of exploring desert plant species. Different parameters were taken for each species, including soil salinity and density. Two zones showed the highest levels of salinity, Daoura and Akhfennir, both in the Tarfaya province with 19.38 and 24.33 mS/cm, respectively. Although, several species were highly tolerant to salinity and were present at moderate to high densities. Among them, one can cite Aeluropus littoralis (Gouan) Parl., Halocnemum strobilaceum (Pall.) M. Bieb. and Suaeda ifniensis Caball. ex Maire. Full article

Hydroponic systems have gained interest and are increasingly used in hot and dry desert areas. Numbers of benefits are offered by hydroponic systems such as the ability to save water, enhance nutrients use efficiency, easy environmental control, and prevention of soil-borne diseases. However, the high consumption of chemical fertilizers for nutrient solution and the sensitivity of closed hydroponic systems to salinity are issues that need solutions. Thus, the main goal of our research activities is to isolate plant growth promoting fungi in order to develop sustainable hydroponic systems. We are working on isolating and testing the possibility to incorporate the cell-free filtrate (CFF) of plant growth promoting fungi (PGPF) in the composition of the nutrient solution. In this work, we isolated six strains of PGPF from the rhizosphere of the halophyte grass Aeluropus littoralis. Phylogenetic analyses of DNA sequences amplified by ITS1 and ITS4 primers identified the isolated fungi as: Byssochlamys spectabilis, Chaetomium globosum, Cephalotheca foveolata, Penicillium melinii, Alternaria tenuissima, and Nigrospora chinensis. The promoting of vigor in tobacco seedlings was used as criteria to evaluate the biostimulant activity of these fungi by adding either their mycelia (DE: direct effect) or their cell-free filtrates (CFF: indirect effect) to the plant-growth media. The best significant growth stimulation was obtained with plants treated by B. spectabilis. However, only the CFFs of Byssochlamys spectabilis (A5.1) and Penicillium melinii (A8) when added at a dilution factor of 1/50 to half-strength nutritive solution (0.5NS) resulted in significant improvement of all assessed growth parameters. Indeed, the A5.1CFF and A8CFF in 0.5NS induced a significant better increase in the biomass production when compared to NS or 0.5NS alone. All fungi produced indole acetic acid in the CFFs, which could be one of the key factors explaining their biostimulant activities. Furthermore, six genes involved in nitrogen-metabolism (NR1 and NRT1), auxin biosynthesis (Tryp1 and YUCCA6-like), and brassinosteroid biosynthesis (DET2 and DWF4) were shown to be induced in roots or leaves following treatment of plants with the all CFFs. This work opens up a prospect to study in deep the biostimulant activity of PGPFs and their applications to decrease the requirement of chemical fertilizers in the hydroponic growing systems. Full article

We report here the isolation and functional analysis of AlTMP1 gene encoding a member of the PMP3 protein family. In Aeluropus littoralis, AlTMP1 is highly induced by abscisic acid (ABA), cold, salt, and osmotic stresses. Transgenic tobacco expressing AlTMP1 exhibited enhanced tolerance to salt, osmotic, H₂O₂, heat and freezing stresses at the seedling stage. Under greenhouse conditions, the transgenic plants showed a higher level of tolerance to drought than to salinity. Noteworthy, AlTMP1 plants yielded two- and five-fold more seeds than non-transgenic plants (NT) under salt and drought stresses, respectively. The leaves of AlTMP1 plants accumulated lower Na⁺ but higher K⁺ and Ca²⁺ than those of NT plants. Tolerance to osmotic and salt stresses was associated with higher membrane stability, low electrolyte leakage, and improved water status. Finally, accumulation of AlTMP1 in tobacco altered the regulation of some stress-related genes in either a positive (NHX1, CAT1, APX1, and DREB1A) or negative (HKT1 and KT1) manner that could be related to the observed tolerance. These results suggest that AlTMP1 confers stress tolerance in tobacco through maintenance of ion homeostasis, increased membrane integrity, and water status. The observed tolerance may be due to a direct or indirect effect of AlTMP1 on the expression of stress-related genes which could stimulate an adaptive potential not present in NT plants. Full article