Journal of Plant Molecular Breeding
Volume:6 Issue: 1, Winter and Spring 2018

Salinity is one of the most important limitation factors in development of agricultural products. Cotton has a relative tolerance to salinity; however, salinity reduces its growth during germination and seedling stages. In this research, split-factorial design of time based on randomized complete block design with 3 replications was used. The real-time PCR results for, root, stem, and leaves of 14-day cotton seedlings of tolerant (Sepid) and sensitive (Thermus14) cotton cultivars with salinity levels from 0 to 16 ds.m-1 were analyzed at three time points, namely 0, 7 and 14 days after salinity stress. Selected genes for Real Time PCR reaction in current study were selected using Cytoscape 3.3.0 software. Results showed that the selected genes GhERF2, GhMPK2, GhCIPK6, GbRLK, GhNHX1, GhGST, GhTPS1 and Gh14-3-3 have positively responded to salinity stress and their expression in the root was higher than in stem and leaf. Moreover, the expression of tolerant genotype (Sepid) was higher than the sensitive cultivar (Thermus 14) one, however, a slight increase in sensitive genotypes was observed in a number of genes (GhERF2 and GhGST) 14 days after starting the stress treatment.

High-molecular weight (HMW (glutenin subunits are encoded by the Glu-1 loci (Glu-A1, Glu-B1 and Glu-D1 (on the long arms of chromosomes 1A, 1B and 1D. In the present study, we constructed genetic linkage map of Glu-D1and then investigated the allelic variation of HMW glutenin subunits at Glu-A1 and Glu-D1 gene loci in 30 Iranian genotypes using Functional markers. Glu-D1 was located at 50.8 cM on chromosome 1D and it was tightly linked to wPt-3743 marker (>1 cM). QTL analysis using composite interval mapping detected one significant QTL for grain yield (GY) on chromosome 1D. This QTL (QYld.abrii-1D) was located between wPt-3743 and Glu-D1 gene locus. Allelic variation of HMW glutenin subunits showed the most frequent alleles were the null allele at Glu-A1and Dx2+Dy12 alleles at Glu-D1loci. The frequency of Null alleles or 1 and 2* were 40% and 60% respectively. Only 9 genotypes included allelic combination of Dx5+ Dy10 and the rest of genotypes had Dx2+Dy12 in the Glu-D1 locus. According to the Nei's genetic diversity index, alleles at Glu-A1 locus have more dispersion in genotypes compared to Glu-D1 locus. The cluster analysis of data based on the Simple Matching coefficient and UPGMC methods, classified the genotypes into four groups. Six genotypes including: Bezostaya, Tajan, Navid, Karaj1, Neyshabour, and Golestan had Ax2* and Dx5+ Dy10 subunits at Glu-A1 and Glu-D1 gene loci. Identification of genotypes with suitable allelic combinations can be used in breeding programs, especially in hybridization.

Pythium ultimum is one of the major causative agents responsible for damping off disease in cucumber plants. In the present study, the effect of potassium phosphite (KPhi) on defense response of P. ultimum-inoculated cucumber plants was investigated. Different plant growth parameters as well as chlorophyll a content were studied to evaluate the healing effects of KPhi. Furthermore, the expression pattern changes of a pathogenesis-related chitinase gene was analyzed via qPCR. Results revealed that KPhi treatment significantly increased growth parameters i.e. shoot length, diameter and mean leaf number in cucumber seedlings. KPhi treatment at 1 and 4 gL-1 caused 31.37% and 94.48% increase in shoot diameter respectively compared to control plants while shoot length of plant treated with 1 and 4 gL-1 KPhi were increased 72.14% and 78.85%, respectively compared to control plants. The chlorophyll a content as well as plant leaf number was significantly increased in plants treated with 1 or 4 gL-1 KPhi compared to control plants. It was interestingly revealed that KPhi application decreased Chitinase gene expression compared to control plants. The findings of the present study would be implemented for designing a controlling strategy to decrease the adverse effect of P. ultimum on cucumber plants.

In order to identify yield and yield component QTLs under control and salt-stress conditions, a population of 254 recombinant inbred lines (RILs), derived from a cross between two bread wheat cultivars, (Roshan / Sabalan), was assessed. Parents and their 254 recombinant inbred lines (RILs) were evaluated in an alpha-lattice design with two replications in two control and saline environments of Yazd in 2011-2012 cropping season. Yield and yield-related traits were evaluated at harvest time. The genotyping was carried out using SSR and DArT markers. A, B and D genomes were covered by 411.8, 620.4 and 67.5 cM, respectively. Also, a total of 48 QTLs were detected on 11 chromosomes for grain yield, biological yield, harvest index, thousand-kernel weight, grain number per spike, spike weight and spikelet number per spike. Roshan (salt tolerance) alleles were associated with an increase yield under saline conditions. SSR markers including gwm146, gwm577, gwm249 (on chromosomes 2A and 7B) were tightly associated with different QTLs. The major effect QTLs were located on chromosomes 1A and 7B for grain yield, harvest index and spike weight, which were explained 10.2%, 12.98% and 29 % of the total phenotypic variance, respectively. These QTLs and markers could be suitable for marker-assisted selection and gene stacking techniques. Moreover, co-located QTLs were detected on chromosome 2B for evaluated traits.

The regulatory sequence of rice alpha amylase 3D gene (Ramy3D) is amongst the most successful expression systems used for recombinant protein expression in plants. In the current study a 995 bp fragment consisting of Ramy3D promoter and its 5′ untranslated region was amplified from the genomic DNA of an Iranian rice cultivar ″Nemat″, using polymerase chain reaction. The amplified fragment was ligated into the pTG19-T vector and the cloned fragment was sequenced. For in silico characterization, the rice specific consensus sequences of TATA-box and YR Rule motifs were scanned against the cloned fragment sequence using FIMO program and the cis acting elements existing in the promoter region were investigated using PlantCare database. A TATA-box motif with the rice specific pattern was identified at upstream position of the transcription start site. The identification of TATA-box in Ramy3D promoter is consistent with its metabolic and tissue specific regulation manner. Several cis regulatory motifs responsible for the metabolic and hormonal regulation of Ramy3D gene were identified including ABRE, G-Box, GC-box, GATA motif and TATCCA T/C motif. In addition, several motifs involved in response to various stimuli such as plant hormones, light and biotic and abiotic stresses were identified which include circadian motif, as-2-box, WUN-motif, TGACG-motif, Skn-1 motif, O2-site, MBS, LAMP-element, I-box, HSE, GCC Box, GATT motif, CGTCA-motif and GAG-motif.

Fenugreek(Trigonella foenum-graecum L.) is a rich source of important medicinal metabolites. This plant belongs to the Fabaceae family. Induced hairy roots by Agrobacterium rhizogenes are a suitable tissue for the production of secondary metabolites, due to the stability and high production of roots without phytohormone in a short time. Different strains of Agrobacterium rhizogenes (A4, ATCC11325 and ATCC15834) were evaluated for induction of transformed hairy roots in T. foenum-graecum L. using seedling explants. The application of hairy root culture may become an alternative method for increase secondary metabolites. Transgenic status of the roots was confirmed by PCR using rolB specific primers. All of the A. rhizogenes strains led to hairy roots induction. The maximum frequency of transformation (97.87%) was obtained using A4 strain in 7-days-old seedling. The 7-days-old explants were inoculated using A4 strain result in highest fresh (0.166 g) and dry (0.080 g) weight of roots. The explants were inoculated by ATCC11325 strain produced hairy roots with highest amount of total phenol (8.113 mg/g DW) and flavonoid content (3.215 µg/g DW).

Agrobacterium-mediated gene transfer method is one of the used methods for genetic transformation in the plant regeneration program. Transformation efficiency can be optimized depending on the strain of bacteria, the genotype of plant and conditions of growth. In this study, the gfp gene was transferred into sugar beet, tobacco, and soybean by Agrobacterium rhizogenes strain AR15834. The effects of bacterial concentrations, antibiotic concentrations and the types of explants and genotypes on the gene transfer efficiency and transgenic hairy roots production were investigated. The explants were inoculated with the bacteria at the adjusted concentrations and two days after the transformation, the explants were transferred to a solid MS medium containing different concentrations of kanamycin antibiotic. According to the results and the examined factors, the optimal conditions to achieving of the maximum production of transgenic hairy roots included bacterial concentration with OD600 = 0.2, cotyledon explant, 50 mg/L kanamycin concentration and Djakel genotype for soybean; bacterial concentration with OD600 = 0.2, leaf with petiole explant and SBSI004 genotype for sugar beet, and bacterial concentration with OD600nm = 0.8 and 100 mg/L kanamycin concentration for tobacco.