Frequency and Spectrum of Mutations Induced by Gamma Rays Revealed by Phenotype Screening and Whole-Genome Re-Sequencing in Arabidopsis thaliana

Genetic variations are an important source of germplasm diversity, as it provides an allele resource that contributes to the development of new traits for plant breeding. Gamma rays have been widely used as a physical agent for mutation creation in plants, and their mutagenic effect has attracted extensive attention. However, few studies are available on the comprehensive mutation profile at both the large-scale phenotype mutation screening and whole-genome mutation scanning. In this study, biological effects on M1 generation, large-scale phenotype screening in M2 generation, as well as whole-genome re-sequencing of seven M3 phenotype-visible lines were carried out to comprehensively evaluate the mutagenic effects of gamma rays on Arabidopsis thaliana. A total of 417 plants with visible mutated phenotypes were isolated from 20,502 M2 plants, and the phenotypic mutation frequency of gamma rays was 2.03% in Arabidopsis thaliana. On average, there were 21.57 single-base substitutions (SBSs) and 11.57 small insertions and deletions (InDels) in each line. Single-base InDels accounts for 66.7% of the small InDels. The genomic mutation frequency was 2.78 × 10−10/bp/Gy. The ratio of transition/transversion was 1.60, and 64.28% of the C > T events exhibited the pyrimidine dinucleotide sequence; 69.14% of the small InDels were located in the sequence with 1 to 4 bp terminal microhomology that was used for DNA end rejoining, while SBSs were less dependent on terminal microhomology. Nine genes, on average, were predicted to suffer from functional alteration in each re-sequenced line. This indicated that a suitable mutation gene density was an advantage of gamma rays when trying to improve elite materials for one certain or a few traits. These results will aid the full understanding of the mutagenic effects and mechanisms of gamma rays and provide a basis for suitable mutagen selection and parameter design, which can further facilitate the development of more controlled mutagenesis methods for plant mutation breeding.

Determination of biological properties of the new synthetic plant growth regulator - spyrocarbon complex with boric acid by means of phytotests

Determining the environmental safety of new synthetic plant growth regulators is an urgent problem. Spirocarbon derivatives were subjected to such determination by means of a specially developed system based on phytotests "germinated seeds". This system allows the values of biometric, cytological and biochemical parameters of the phytotest to determine the toxic, cytotoxic, genotoxic (mutagenic) effects and induction of molecular stress by the synthetic chemical substance being tested. This system was used to establish the biological properties of a new drug - a complex of spirocarbon with boric acid - in relation to five phytotests monocotyledons and dicotyledons plants. Phytotesting was performed in the spectrum of concentrations (10-7-10-2 mol/dm3) of this drug. It demonstrated either the absence or presence of a weak toxic effect on phytotests, which did not exceed 30%. The study showed that the plant growth regulator spirocarbon in combination with boric acid has growthregulating properties, the manifestation of which depends on the concentration of the drug and the species characteristics of plants. Only the maximum concentration (10-2 моль/дм3) of the tested drug is slightly toxic to plants. The obtained results testify to the biological efficiency and ecological safety of the synthesized drug. This allows us to recommend it for use in agricultural practice.

Cannabis: Joints of Mental Illness

With the increasing push to legalise cannabis in western nations there is an estimation that the potential impact of this policy change on vulnerable population such as those with mental illness, including schizophrenia, mood and anxiety disorders. Cannabis is the most likely used illicit drug worldwide. Cannabis sativa is an important herbaceous species originating from central Asia which has been used in folk medicine. Despite the widespread use of cannabis among young people little research attention has been given to the development of pscyhometrically sound measures specific to cannabis related problems. The laws governing cannabis are evolving worldwide are associated with changing pattern of use. Patients with a serious mental illness often use cannabis at higher rates than the general population. Cannabis may induce or exaberate a number of mental health problems. The main psychoactive drug in cannabis is ?9 tetrahydrocannabinol (THC). Cannabidiol, a non-toxicating cannabinoid found in some forms of cannabis, may offset some of these acute effects. Chronic use of cannabis is associated with psychiatric, respiratory, cardiovascular and bone effects. It also has oncogenic, teratogenic and mutagenic effects, all of which depend upon dose and duration of use. The present article mainly reviews about the association between cannabis and mental health.

Acclimation of cadmium-induced genotoxicity and oxidative stress in mung bean seedlings by priming effect of phytohormones and proline

In this research, eight local mung bean (Vigna radiata) varieties were analyzed for their performance against two levels of CdCl2 solution (0.3 and 0.5 mM) alone and priming with gibberellic acid (GA3) (100 μM), salicylic acid (SA) (50 μM) and proline (5 mM) solution prior to Cd exposure. Mung bean seedlings were analyzed for disturbance in cytological, morphological, biochemical and enzymatic parameters under cadmium stress. For cytological studies, 48 h grown mung bean seedlings root tips were used to prepare slides and studied for percent mitotic index (MI%) and to calculate percent C-mitosis, laggard, sticky and fragmented chromosomes, pictures were captured by a Nikon camera (DS-Fi 1 Japan) attached with a microscope. One-week grown mung seedlings were studied for growth traits, malondialdehyde (MDA), protein, proline and antioxidant enzymes. ANOVA and DMR test of this research revealed that all the tested mung bean varieties and treatments were significantly different regarding mitotic index and number of chromosomal aberrations. Both the Cd treatments exhibited increased total chromosomal aberrations with different types and a maximum decrease in MI%. In pretreated samples, GA3, SA and proline serve as mitigating agents that reduce mutagenic effects of Cd in mung bean by increasing MI% and decreasing chromosomal aberrations as compared to non-pretreated samples. Both the Cd treatments showed a decrease in all growth traits. Total proteins were also found to be significantly reduced in a dose-dependent manner in all genotypes. Cd treatment increased the activities of all antioxidant enzymes tested. Cd caused oxidative damage as indicated by elevated levels of MDA content in treated samples in comparison to control. Proline content levels were also high in Cd treated seedlings indicating stress. Results demonstrated that pretreatment with phytohormones and proline before Cd were found to improve all morphological parameters, by altering antioxidant enzymes activities along with a decrease in MDA and proline contents as well. It was further noticed that the performance of GA3 was better at 0.3 mM Cd treatment while SA was found to be a good mitigating agent at 0.5 mM Cd stress in all tested mung bean varieties. This research concluded less deleterious effects of Cd on AZRI-2006 while more sensitivity to NM-51 towards Cd. Priming with phytohormones and proline is a user-friendly, economical, and simple mitigation strategy to reduce Cd toxicity in plants and get better yield from contaminated lands.