Research on the basic interaction of radiation with biological systems has contributed to human society through various applications in medicine, agriculture, pharmaceuticals and in other technological developments. In the agricultural sciences and food technology sectors, recent research has elucidated the new potential application of radiation for microbial decontamination due to the inhibitory effect of radiation on microbial infestation. The last few decades have witnessed a large number of pertinent works regarding the utilization of radiation with special interest in γ-rays for evolution of superior varieties of agricultural crops of economic importance. In this review, general information will be presented about radiation, such as plant specificity, dose response, beneficial effects, and lethality. A comparison of different studies has clarified how the effects observed after exposure were deeply influenced by several factors, some related to plant characteristics (e.g., species, cultivar, stage of development, tissue architecture, and genome organization) and some related to radiation features (e.g., quality, dose, duration of exposure). There are many beneficial uses of radiation that offer few risks when properly employed. In this review, we report the main results from studies on the effect of γ-irradiations on plants, focusing on metabolic alterations, modifications of growth and development, and changes in biochemical pathways especially physiological behaviour.

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Introduction and RationaleThe detection of bioavailable phenol is a very important issue in environmental and human hazard assessment. Despite modest developments recently, there is a stern need for development of novel biosensors with high sensitivity for priority phenol pollutants. DmpR (Dimethyl phenol regulatory protein), an NtrC-like regulatory protein for the phenol degradation of Pseudomonas sp. strain CF600, represents an attractive biosensor regimen. Thus, we sought to design a novel biosensor by modifying the phenol detection capacity of DmpR by using mutagenic PCR.MethodsBinding sites of ‘A’ domain of DmpR were predicted by LIGSITE, and molecular docking was performed by using GOLD to identify the regions where phenol may interact with DmpR. Total five point mutations, one single at position 42 (Phe-to-Leu), two double at 140 (Asp-to-Glu) and 143 (Gln-to-Leu), and two double at L113M (Leu-to- Met) and D116A (Asp-to- Ala) were created in DmpR by site-directed mutagenesis to construct the reporter plasmids pRLuc42R, pRLuc140p143R, and pRLuc113p116R, respectively. Luciferase assays were performed to measure the activity of luc gene in the presence of phenol and its derivatives, while RT-PCR was used to check the expression of luc gene in the presence of phenol.ResultsOnly pRLuc42R and pRLuc113p116R showed positive responses to phenolic effectors. The lowest detectable concentration of phenol was 0.5 µM (0.047 mg/L), 0.1 µM for 2, 4-dimethylphenol and 2-nitrophenol, 10 µM for 2, 4, 6-trichlorophenol and 2-chlorophenol, 100 µM for 2, 4-dichlorophenol, 0.01 µM for 4-nitrophenol, and 1 µM for o-cresol. These concentrations were measured by modified luciferase assay within 3 hrs compared to 6–7 hrs in previous studies. Importantly, increased expression of luciferase gene of pRLuc42R was observed by RT-PCR.ConclusionsThe present study offers an effective strategy to design a quick and sensitive biosensor for phenol by constructing recombinant bacteria having DmpR gene.