Journal of Plant Molecular Breeding
Volume:5 Issue: 2, Summer and Autumn 2017

Phytophthora species are considered as the major cause of several plant diseases resulting in huge yield losses in agricultural crops. Despite years of effort to develop Phytophthora resistance varieties, there is no reports of a resistant cucumber variety. In this study, the effect of concomitant application of potassium phosphite (KPhi) and chitosan on some physiological and molecular responses of Phytophthora capsici-challenged cucumber plants were investigated. Cucumber plants were treated with KPhi and/or Chitosan at different concentrations and were then inoculated with zoospores of P. capsici and leaf samples were collected at different time courses. Results showed that Guaiacol peroxidase (GPOD) enzymatic activity surged immediately at first and second days after pathogen inoculation with a peak in plants treated with 4 gL-1 KPhi 2 days after inoculation. Compared to GPOD, the highest superoxide dismutase (SOD) activity was observed in the same treatment but later at 5 days after inoculation. It was indicated that the activity of antioxidant enzymes was greatly influenced by application of either KPhi or chitosan while their activity was not remarkably enhanced in control plants. qPCR analysis revealed that the highest increase in glutathione peroxidase (gpx) gene expression was achieved in plants concomitantly treated with 4 gL-1 KPhi and 200 mgL-1 chitosan 5 days after inoculation. The findings of this study provide novel information regarding inducing mechanisms of KPhi and chitosan which may be effective in mitigating disease severity.

Callus induction and regeneration of fennel from embryo explants were stabilized in the presence of cefotaxime antibiotic and different plant growth regulators (PGRs). The experiments were conducted under a factorial experiment, based on a completely randomized design (CRD). Genotypes; Fasa, Meshkinshar and Hajiabad were applied under different concentration of cefotaxime (0 and 100 mg l-1), NAA (0 and 0.2 mg l-1), IAA (0 and 0.4 mg l-1) and BAP (0, 0.5 and 1mg l-1). Regeneration, proliferations and root induction were taken placed on studied media, after 35 days without sub-culturing. The highest rate of proliferation with 200 shoots per explant was observed on B5 medium, containing100 mg l-1 cefotaxime and 1.0 mg l-1 BAP.  Callus induction and proliferations were observed in all media containing 100 mg l-1 cefotaxime that can be related to auxin like activity of cefotaxime in fennel tissue culture.

Cotton (Gossypium hirsutum L.) is a source of edible oil and fatty acids (FAs). In this study, embryos’ explants were cultured in MS medium with different concentration of  plant growth regulators (phytohormones) include BA, IAA, IBA, 2, 4- D and NAA, to finding the relationship of hormone and organogenesis with oil and FAs content. Oil was extracted with chloroform and methanol. FAs of oil were esterificated and methylated for GC-MS analysis. The seeds and shoots oil were 36.1 and 4.5%. Oil of regenerated shoots (33.3%) in T2 with 0.25 BA and 5 mgl-1 IAA was higher than to seeds, shoots and all regenerated organs.Unsaturated FAs increased in some treatments depending on the type of phytohormone and organogenesis.  Amounts of all FAs of regenerated root of T4 in BA/IBA were lesser than to other samples. Our results showed that Sahel cultivar of cotton can synthesize 12 types of FAs, but some of those FAs are made under certain conditions depending on the type and concentration of phytohormones and organogenesis.

Hot pepper (Capsicum spp.) is an economically important spice widely cultivated and consumed in Ethiopia. In spite of its wide importance, there is no information available on the molecular genetic diversity of this crop. Cultivars characterization is an important link between the conservation and utilization of plant genetic resources in various breeding programs. Using five ISSR primers, a total of 37 scorable bands were generated of which 35 (94.6%) were polymorphic bands. The diversity of polymorphic bands within population ranged from 51.35% to 91.89 % with a mean of 66.6 %, Nei’s genetic diversity of 0.19 - 0.30 with a mean of 0.28, and Shannon information index of 0.29 - 0.45 with a mean of 0.43. With all diversity parameters, the highest diversity was obtained from amhara2 populations, whilst the lowest was from Oromia2. From Jaccard’s pairwise similarity coefficient, Oromia1 and oromia2 were the most related populations exhibiting 0.956 similarity and Semn omo and Amhara 2 were the most distantly related populations with similarity of 0.827. Clustering was showed that there is strong correlation between geographic distance and genetic diversity of Ethiopian hot peppers cultivars because geographically closely related species have been clustered together. Amhara 2 populations exhibited the highest genetic diversity so that the populations should be considered as the primary sites in designing conservation areas for this crop in Ethiopia.  Further, it is suggested that molecular markers are valid tags for the assessment of genetic diversity in Capsicum spp. cultivars.

DNA fingerprinting has become an important tool for diversity assessment and varietal identification in plant breeding programs. Semi- random PCR primers targeting intron-exon splice junctions (ISJ) were used to evaluate the potential of these markers in identification and classification of rice genotypes. A total of 12 ISJ primers were used for screening fourteen Egyptian rice genotypes, including six Japonica, four Indica and four Indica/Japonica rice genotypes. A total of 117 amplified fragments were generated among which 76 fragments were polymorphic revealing average polymorphic ratio of 58.9%. Number of amplified fragments per genotype across the primers ranged from 65 in Japonica rice variety Sakha101 to 85 in Indica/Japonica rice variety Giza179. Number of polymorphic amplified fragments ranged from 3 for primer ISJ-1 to 24 for primer ISJ-2. The average numbers of amplified bands per primer per genotype were 16.71 and 10.24, respectively. Polymorphic information content (PIC) values ranged from 0.289 for ISJ-9 to 0.480 for ISJ-1 with an average of 0.375. The coefficient of similarities based on semi-random data among the studied genotypes ranged from 0.53 to 0.9 with an average of 0.66. All genotypes clearly grouped into two major clusters in the dendrogram at 58% similarity based on Jaccard’s similarity index. The first cluster represents the Indica and Indica/Japonica rice genotypes, while the second cluster represents the Japonica genotypes. These results indicate that fingerprinting using semi-specific DNA markers may be an efficient tool for varietal identification and assessing genetic diversity in rice. The results highlight the existing diversity among the studied genotypes and hence their potential use in breeding programs. The simplicity and reproducibility of ISJ markers indicates the potential utilization for molecular characterization, identification and purity assessment of rice genotypes.

Isolation of high-quality RNA is one of the most crucial methods in molecular biology. RNA extraction from woody plants has been problematic due to the presence of rigid and woody tissues, large amounts of polysaccharides, polyphenols and other secondary metabolites. Here we present a suitable protocol for RNA isolation from a wide range of woody plants that includes eight gymnosperms and four angiosperms. The method is based on the CTAB protocol which was modified by adding sodium citrate and two helper buffers. Agarose gel electrophoresis showed a good RNA integrity and total RNA profile that includes all expected RNA bands. Also, DNA and protein contaminations were not observed. Spectrophotometric quantification of RNA samples by NanoDrop showed that the average RNA yields ranged from 35.68 to 216.98 µg per gram fresh weight, that is enough to proceed into cDNA synthesis and other RNA-related works. Both the A260/A280 and A260/A230 ratios were in the desired ranges, indicating that RNA was of high purity and without protein, polyphenol, and polysaccharide contamination. The efficiency of isolated RNA for downstream applications was verified by real-time PCR and successful amplification of a long cDNA. Finally, some advantages and possible applications of the method are also mentioned.

Cornelian cherry (Cornus mas L.), considered as the ancestor of cultivated trees in Arasbaran region, is a medicinally and economically plant species. However, little is known about genetic diversity, breeding programs, and population structure of this species in mentioned region. Keeping this in view, the main objectives of present study were to analysis the genetic diversity, phylogenetic relationships and population structure of cornelian cherry genotypes from Arasbaran region using Inter Simple Sequence Repeat molecular markers. Utilized primers amplified 153 bands, of which 98 bands were polymorphic (64% polymorphism). Highest Jaccard’s similarity coefficient was obtained 0.777. Based on Unweighted Pair Group Method with Arithmetic Averages, genotypes were divided into seven major groups. On the other hand, Principal Coordinate Analysis (PCoA) as a complementary method to cluster analysis demonstrated genotypes grouping in phylogenetic dendrogram. Relatively low amount of three main components in Principal Component Analysis (PCA) (41.464%) indicated the scattering distribution of utilized primers’ sequence in cornelian cherry genome. The mean values of polymorphism information content, marker index, resolving power, observed number of alleles, effective number of alleles, Nei’s gene diversity, and Shannon’s information index were 0.230, 1.769, 4.7, 1,642, 1.498, 0.271, and 0.392 respectively. Population structure analysis showed the seven groups or sub- populations (K= 7) when the amount of K value was set at K= 2 to K= 10, which demonstrated the results of phylogenetic dendrogram and Principal Coordinate Analysis (PCoA). Results of this study can be useful for planning future studies on cornelian cherry germplasm and breeding programs.