L-carnitine is a fundamental ammonium compound responsible for energy metabolism in all living organisms. It is an oxidative stress regulator, especially in bacteria and yeast and lipid metabolism in plants. Besides its metabolic functions, l-carnitine has detoxification and antioxidant roles in the cells. Due to the complex interrelationship of l-carnitine between lipid metabolism and salinity dependent oxidative stress, this study investigates the exogenous l-carnitine (1 mM) function on seed germination, cell division and chromosome behaviour in barley seeds (Hordeum vulgare L. cv. Bulbul-89) under different salt stress concentrations (0, 0.25, 0.30 and 0.35 M). The present work showed that l-carnitine pretreatment could not be successful to stimulate cell division on barley seeds under non-stressed conditions compared to stressed conditions. Depending on increasing salinity without pretreatment with l-carnitine, the mitotic index significantly decreased in barley seeds. Pretreatment of barley seeds with l-carnitine under salt stress conditions was found promising as a plant growth promoter and stimulator of mitosis. In addition, pretreatment of barley seeds with l-carnitine alleviated detrimental effects of salt stress on chromosome structure and it protected cells from the genotoxic effects of salt. This may be caused by the antioxidant and protective action of the l-carnitine. Consequently, this study demonstrated that the exogenous application of 1 mM l-carnitine mitigates the harmful effects of salt stress by increasing mitosis and decreasing DNA damage caused by oxidative stress on barley seedlings.

BackgroundHybridization and introgression are common phenomena among oak species. These processes can be beneficial by introducing favorable genetic variants across species (adaptive introgression). Given that drought is an important stress, impacting physiological and morphological variation and limiting distributions, our goal was to identify drought-related genes that might exhibit patterns of introgression influenced by natural selection. Using RNAseq, we sequenced whole transcriptomes of 24 individuals from three oaks in southern California: (Quercus engelmannii, Quercus berberidifolia, Quercus cornelius-mulleri) and identified genetic variants to estimate admixture rates of all variants and those in drought genes.ResultsWe found 398,042 variants across all loci and 4352 variants in 139 drought candidate genes. STRUCTURE analysis of all variants revealed the majority of our samples were assignable to a single species, but with several highly admixed individuals. When using drought-associated variants, the same individuals exhibited less admixture and their allele frequencies were more polarized between Engelmann and scrub oaks than when using the total gene set. These findings are consistent with the hypothesis that selection may act differently on functional genes, such as drought-associated genes, and point to candidate genes that are suggestive of divergent selection among species maintaining adaptive differences. For example, the drought genes that showed the strongest bias against engelmannii-fixed oak variants in scrub oaks were related to sugar transporter, coumarate-coA ligases, glutathione S-conjugation, and stress response.ConclusionThis pilot study illustrates that whole transcriptomes of individuals will provide useful data for identifying functional genes that contribute to adaptive divergence among hybridizing species.Electronic supplementary materialThe online version of this article (10.1186/s12863-018-0677-9) contains supplementary material, which is available to authorized users.

The effects of 60 Cobalt (60 Co) gamma radiation on cell division and chromosomal structure in M 1 generations of three varieties (NKU Lider, Bezostaja and GK Beke's) of Triticum aestivum L. genotypes were determined in this study. To understand and compare the tolerance of on three bread wheat varieties to gamma radiation (100, 200 and 300Gy), the frequency of mitotic index, phase indices and genotoxicity rate were scored and statistically interpreted under irradiated and unirradiated conditions, respectively. In parallel with the increasing radiation dose, mean mitotic index rate decreased in NKU Lider and GK Beke's genotypes. 100Gy 60 Co gamma radiation application of NKU Lider was the most powerful genotype to increase mitotic activity as compared to other genotypes. However; depending on increasing dose of gamma radiation, cell division decreased in all studied genotypes except 200Gy application of Bezostaja genotype. Moreover, genotoxicity index of M 1 generation in NKU Lider genotype was decreased in all studied radiation doses with the increasing dose of 60 Co. Furthermore, three different variety of T. aestivum L. seeds treated with different doses of 60 Co gamma radiation showed many aberrant chromosomes such as disorderly prophase, stickiness, uncoiling chromosomes, disrupted equatorial plate, fragment, micronucleus, alignment anaphase, fault polarization, anaphase and telophase bridges, lagging chromosomes and stickiness in all mitotic phases. Consequently, the results suggest that gamma radiation effects are specific to the radiation dose and species, and even show different responses in different varieties of the same species.

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