Iranian Journal of Genetics and Plant Breeding
Volume:10 Issue: 1, Apr 2021

During the past few decades, the problems caused by the stratospheric ozone reduction has stimulated remarkable research on higher plant responses to UV-B radiation. Depletion of the stratospheric ozone layer is leading to an increase in ultraviolet-B (UV-B: 280–320 nm) radiation reaching the earth’s surface. This has raised interest in the possible consequences of increased UV-B levels on plant growth and development and the mechanisms underlying these responses. Although the effects of UV-B are now well characterized at the physiological level, little is known about the involved cellular and molecular mechanisms. Recent studies have shown that UV-B affects a number of important physiological processes, such as photosynthesis, through effects on gene expression. However, little research has addressed the reproductive biology of plants. The purpose of this study was to investigate the effects of UV-B radiation on reactive oxygen species (ROS) accumulation and antioxidant defense system in relation to germination and pollen tube growth of canola (Brassica napus L.). Our results illustrated that increased UV-B radiation decreased the pollen germination rate and tube length in vitro. Production of superoxide anion radical (O2•−) and hydrogen peroxide (H2O2) increased by UV-B radiation treatment, and their accumulation resulted in lipid peroxidation. The activities and gene expression of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were decreased by enhanced UV-B radiation. The increased ROS and lipid peroxidation, as well as decreased antioxidant activities may be attributed to the effects of UV-B radiation on pollen germination and tube growth.

This study aimed to investigate the genetic diversity of 140 barley advanced lines, using Selection Index of Ideal Genotype (SIIG) and Adjusted Selection Index of Ideal Genotype (ASIIG) indicators for introduction and cultivation of suitable lines in rainfed conditions. The highest coefficient of variation was related to the type of spike, flag leaf area, seeds per spike, peduncle length, flag leaf width, and early growth vigor. The stepwise regression showed that the early growth vigor, 1000-seeds weight, spike type, days to heading, plant height, number of seeds per spike, and flag leaf length were the most critical components, which affect the grain yield under the rainfed conditions. The results of SIIG showed that lines 4, 43, 47, 40, 70, 96, 137, 3, 57, and 45 were the best lines with the highest SIIG values. The SIIG index divided all lines into seven groups; the average grain yield of lines in groups I and II were higher than the average grain yield of control cultivars and the other groups. According to ASIIG plots, lines 47, 3, 43, 45, 137, 96, and 40 were placed in the ideal quarter. Finally, the SIIG and ASIIG were compatible in selecting the best lines. ASIIG was more suitable for separating the ideal lines, because it participated all traits commensurate with their importance in the end product quantity and quality.

Different strains of a bacterial culture can undergo phenotypic variation upon continuous passages. These changes often cause a reduction or loss of bacterial metabolic potential and ultimately lead to a decrease in production yield. The aim of this study was to address this question; is it possible to restore the reduced coenzyme Q10 production of a varied strain of Gluconobacter to a higher level? The main strain studied in this study was Gluconobacter japonicus FM10, from which the FM20 strain was obtained. FM20 strain was a varied strain whose ability on coenzyme Q10 production was reduced during some continuous passages. FM30 strain was obtained from FM20 strain by restricting the available oxygen. The amount of coenzyme Q10 produced by all three strains was measured. The activities of glycerol dehydrogenase and sorbitol dehydrogenase were also measured. The results showed that coenzyme Q10 production in FM30 strain that had been exposed to restricted oxygen was several times higher (6.3 mg/L) than the varied FM20 strain (0.8 mg/L), and even the original FM10 strain (2.7 mg/L). The investigation of the enzymes activities showed that glycerol dehydrogenase and sorbitol dehydrogenase activities of FM30 strain were higher than those of the others (0.66 and 0.52 U mg-1, respectively). It can be concluded that by using some strategies, the metabolic potential of some varied strains can be restored. For strictly aerobic bacteria, Gluconobacter, the oxygen restriction may be an effective strategy for the restoration of coenzyme Q10 production ability.

This is the first report on the analysis ISSR markers for assessing the genetic variation in Arnebia pulchra. As the rate of cell division and propagation in A. pulchra is very low, the achievement of biomass in this valuable plant requires techniques and strategies that can guarantee the survival of the callus. The present study was performed to investigate genetic variation in two in vitro culture samples of the medicinal plant A. pulchra including new (one month old) and old (four years old) calli versus seeds by Inter Simple Sequence Repeat (ISSR) marker. In total, 79 bands were produced by 10 ISSR primers. The total expected heterozygosity (He) was calculated 0.028 and the greatest value was contributed to seeds samples (0.054) followed by old and new calli, respectively. The maximum values of different alleles (Na), effective alleles (Ne) and Shannon’s index were also observed in seeds. Cluster analysis was performed in the form of dendogram to indicate the genetic stability of the samples. UPGMA tree discriminated samples in two major groups and principal component analysis (PCoA) confirmed the clustering result. The first major cluster included seeds and the second involved new and old calli. Although it was thought that the morphological changes of A. pulchra could be due to the somaclonal variation caused by successive subcultures, however, the results indicated that the new and old calli were clustered in the same group. Therefore, it can be concluded that the morphological changes of the old and new calli could be due to environmental parameters or epigenetic changes but not directly due to somaclonal variation.

Magnetic iron oxide nanoparticles (Fe3O4-NPs) offer numerous applications in agriculture, pharmaceutical, and food industries. In this study, Fe3O4-NPs were effectively phytosynthesized by environmentally friendly hairy root extracts. The A4 strain of Agrobacterium rhizogenesis was used to induce the hairy roots of Nepeta bornmuelleri. Leaves in N. bornmuelleri contain important ingredients such as 1, 8 cineol that is one of the most well-known secondary metabolites. The phytosynthesis of Fe3O4-NPs was verified and described by Ultraviolet-Visible spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), and thermogravimetric analysis (TGA). The NPs were clustered with a size of less than 20 nm in FESEM analysis and 20-100 nm in TEM and HRTEM analysis. XRD pattern showed a peak of Fe3O4-NPs at 35.28° (220 nm). In the FTIR experiment, amines, alkanes, carbonyls, fluorides, and alcohols were detected as organic molecules involved in the synthesis of NPs. The average size of NPs in their liquid medium was about 53.39 nm, according to DLS analysis. According to TGA analysis, NPs maintained 82% of their weight at a temperature above 700 °C. According to the results of TGA study, Nepeta’s fast-growing hairy roots generated highly pure NPs. TGA analysis revealed that the weight loss of synthesized NPs in hairy roots was smaller than those identical samples produced in the extracts obtained from aerial parts of the plants. The 1, 8 cineol in the hairy root extracts measured by gas chromatography was found to be around 0.001%.

Castor (Ricinus communis L.), besides being cultivated for its oil, its seed is used to prepare a food condiment (Ogiri). Ogiri is a highly proteinous fermented food condiment traditionally consumed in Nigeria and some other parts of Africa. In the present study, a step-wise selection was carried out for ideal genotypes that could be cultivated for the condiment in Nigeria. The trial was conducted based on the basic protocol for varietal release and registration in Nigeria. The trials were carried out on replicated plots from 2014 through 2019, using Randomised Complete Block Design. Selections were made from seventeen (17) large seeded castors based on yield performances, reaction to pests, nutrient contents, yield stability and farmers’ preference. Results showed that only eight, out of the 17 genotypes initially evaluated, performed above the norm in all the traits considered at the on-station assessments. The eight genotypes had appreciable seed yield (726.96 kg/ha to 1481.01 kg/ha), adequate seed oil content (29.11% to 39.60%), good nutrient contents, and tolerance to major insect pests and disease. Based on the stability assessment, two genotypes (Acc001 and Acc045) were identified as the most ideal for farmers’ participatory selection. The two genotypes recorded higher seed yields and stability across the locations. The on-farm performance appraisal revealed high farmers’ preference for the genotype Acc001 because of its higher yield and market value. The genotype Acc001 could be recommended for registration and release in Nigeria.

Damask rose is a valuable oil bearing species whose various products are widely used in food, cosmetics and pharmaceuticals. In this study, fifteen genotypes from different regions of Iran were cultivated in a randomized complete block design with 3 replications and 3 plants per plot. During two crop years, the morphological traits, flower yield and yield components were measured. The essential oils (EOs) extracted using a modified clevenger system according to British Pharmacopoeia (1993). The EO content (percentage) and EO yield were calculated for each of the R. damascena (DR) genotypes. The data were analyzed by univariate and multivariate analysis. The results showed a significant difference (p<0.01) between the years and the genotypes for all the traits except the essential oil percentage. The highest flower fresh yields (7383.8 kg.ha-1) were obtained in Fars1 and then 6016 (kg.ha-1) in Isfahan5 and the lowest yield (2566.1 kg) was obtained in LOR1. The highest content of EO (%) was obtained in Kermanshah9 genotype (0.048%) and in Isfahan9 (0.044%), respectively, and the lowest content of EO (%) was obtained in Fars1 (0.024%). The highest EO yields (2.25 kg.ha-1) were observed in Isfahan5 and (2.18 kg.ha-1) in Isfahan9, respectively, and the lowest EO yields was observed in Lorestan1 (0.81 kg.ha-1) and Azarbaijan-e-gharbi1 (0.92 kg.ha-1). The cluster analysis classified the genotypes into four group. The results of PCA showed that Fars1 had the highest flower yield and Isfahan8 had the highest EO yield.

Lepidium spp. (Brassicaceae) are herbaceous plants grown worldwide and considered as vegetable, phytofood or medicinal plants. The genetic variation and genetic structure of 22 Lepidium (L.) accessions representing 3 species (L. sativum, L. draba and L. latifolium) from Iran were assessed using 14 Start Codon Targeted (SCoT) markers. A high polymorphism (98.4%), polymorphic information content (0.35) and polymorphic bands (4.5) indicated that SCoT markers are reliable for genetic variation analysis in Lepidium spp. Mean values of resolving power (Rp), marker index (MI) and effective multiplex ratio (EMR) were 5.0, 1.6 and 4.4, respectively. The highest percentage of polymorphic loci (92.2%), Nei’s gene diversity (0.35) and Shannon index (0.51) were observed in L. sativum. According to analysis of molecular variance (AMOVA), genetic variation within species was higher than between species. The highest similarity was found between L. draba and L. latifolium (r=0.94). A high level of gene flow was estimated in accessions of Lepidium species (Nm=2.65), which is further confirmed by neighbor-joining (NJ) cluster analysis, principal coordinates analysis (PCoA) and STRUCTURE analysis, that could reveal a poor separation between Lepidium species. NJ cluster analysis divided the Lepidium accessions into three groups, and the grouping of accessions was generally consistent with their origins. This study is the first to explore and prove SCoT markers suitability in genetic diversity of Lepidium spp. The genetic analysis information provided here would be helpful for breeding programs and germplasm conservation in Lepidium species.

Spring frost injury is a major environmental limit for the productivity of stone fruits such as almond. Thus, it is important to screen and breed spring frost tolerant trees. Among molecular markers, SSR derived from EST sequences are more desirable for breeding programs. In our previous study, we employed a frost treatment for flowers of a frost-tolerant almond genotype at full blooming stage as the important phenological stage to study frost stress. The transcriptomes of the frost-treated and non-frost-treated flowers (after post-thaw period) were analyzed and compared by using next generation sequencing technology. A total of 63218 sequences were generated and analyzed using SSR-Locator. In total, 2680 SSRs were identified and 2601 of sequences contained SSRs. In 11 sequences, there was more than one EST-SSRs. Among the potential EST-SSRs, five types of the motifs were identified; di-nucleotide and tri-nucleotide had the highest frequencies followed by penta-nucleotide, hexa-nucleotide and tetra-nucleotide repeats. Our study revealed that di- and tri-nucleotide motifs are more frequent. TA/TA and GA/TC were the most abundant di-nucleotide motifs while GAA, AAC and ACC were common in tri-nucleotide SSRs. GO annotation showed that the top GO terms associated with SSRs containing tri-nucleotide motif were involved in the regulation of transcription, regulation of cellular biosynthetic processes, regulation of gene expression, regulation of cellular processes, response to stress and response to stimulus. Our study is the first report on SSR development for fully open flowers of a frost-tolerant almond genotype.

Drought stress is one of the most important limiting factors, decreasing the production of vegetable crops in the global scale. The aim of this study was initially to examine two extreme seeded watermelon genotypes (C6 and C12) using physiological and biochemical characteristics in response to drought stress. The expression of key genes against drought stress (CLsHSP18.1A and CcNAC2) were also investigated using RT-PCR in the same condition. The highest concentration of proline content occurred in C6 (tolerant genotype) with 9.93 µmol/g fresh leaf after 5 days water stress. Malondialdehyde (MDA) and electrolyte leakage were significantly higher in C6 during drought stress. The result of gene expression levels for CLsHSP18.1A and CcNAC2 indicated that there was a significant increase of expression in both genes in response to drought stress. In C6, drought stress after four days caused 2.5 fold up-regulation of CLsHSP18.1A compared with the control (p≤0.05), but in C12 (susceptible genotype), the expression decreased 1.4 fold compared to the relevant control. Semi-quantitative measurement of CcNAC2 expression in both genotypes showed that maximum up-regulations occurred after two days of stress with the highest level in C6. Furthermore, four days after stress, a significant decrease occurred in the expression of this gene in both genotypes, but there was not a significant expression difference between susceptible C12 and its relative control. Overall, the expression levels of both targeted genes were higher in tolerant (C6) than that of susceptible genotype (C12) in all time points of drought stress. It seems that these genes may play a role in mechanisms involving in the drought tolerance in watermelon which could be important in molecular breeding of drought tolerant watermelons.

Ajowan (Trachyspermum Ammi L.) is one of the most important medicinal plants native to the Middle East and Iran. The antibiotic properties of its essential oils are related to the relatively high content of thymol. In this study, the possibility of hairy root production was investigated in a pre-experimental study considering many factors affecting transgenic efficiency, including explant type, immersion time, and the type of culture medium. Optimal conditions for the pre-experiment were set up based on the completely randomized design with seven Agrobacterium rhizogenes strains (A3, A6, A7, 4404, AATCC15834, R1000, A4) and six selected Ajowan ecotypes (Ardebil, Shiraz, Arak, Sarbishe, Qom, and Rafsanjan). The root-related morphological characteristics were measured to study the effect of main factors on the hairy root production and the bacterial strains in terms of hairy root induction. Based on the results, the highest percentage of hairy roots in Ardebil ecotype was induced by ATCC15834 strain (50%) and the lowest percentage was related to Rafsanjan ecotype induced by A6 (10%). The highest positive and significant correlation was observed in dry and wet weights (r=0.95), root frequency percentage and root length (r=0.80). The highest amount of phenolic compounds in hairy roots (240 mg/g dry weight matter) was associated with the Ardebil ecotype induced by strain ATCC15834. In this study, Shiraz and Ardebil ecotypes were identified as the best ecotypes, A4 and ATCC15834 strains as the most suitable strains, and suggested for future studies.