فصلنامه ژنتیک نوین
سال چهاردهم شماره 2 (پیاپی 57، تابستان 1398)

Stevia rebaudiana is a sweet herb containing steviol glycosides (SGs), which is used as a natural sweetener. The study of gene expression patterns in response to elicitor treatments is important for biotechnological purposes. Nowadays, salicylic acid (SA) is an abiotic elicitor that has commonly been applied to elicit secondary metabolites accumulation in tissue culture of medicinal plants. Exclusive synthesis of steviol starting from terpenoied pathway of chloroplast and with production of kaurenoic acid 13-hydroxylase (KA13H) leads to the synthesis of glycosides such as stevioside and ribodioside A. In this study, the effect of different concentrations of salicylic acid (SA) was evaluated on some morphological traits, the amount of steviol glycosides (SGs) production and gene expression of KA13H. Accordingly, the morphological traits significantly changed by increasing the salicylic acid concentration. Based on the HPLC and gene expression data, the highest SG level and KA13H expression were observed at a concentration of 50 μM of SA. Moreover, rebaudioside A was higher at 75 μM of SA. It is notable that salicylic acid is more effective on the ratio of glycosides than the type of them. However, more investigations are needed to confirm the impact of the post-transcriptional, translational, and post-translational processes on SGs production.

This study was conducted to evaluate phylogenetic and taxonomic statue of Alburnoides parhami using COI molecular marker and morphological data. For this purpose, topotypes of 10 species of the genus Alburnoides were sampled from 6 inland water basins during 2014-2016. For morphological study, 29 morphometric and 8 meristic characters were measured and counted. For morphological comparison of this species and its closest relative based on molecular data i.e. A. holciki, Principal Component analysis and MANOVA were used. The gene of COI were analyzed using Maximum likelihood and Bayesian methods to reconstruct their phylogenetic tree. Based on the results, A. holciki and A. parhami could not differentiated based on morphological characteristics. The molecular results based on COI gene revealed a small divergence i.e. these two species were different in one nucleotide position based on nucleotide parsimony polymorphism. Therefore, it is suggested that A. parhami is junior synonym of A. parhami.

In order to study the mechanism of drought tolerance and expression of the genes involved in osmotic regulation in wheat, a factorial experiment based on a randomized design with three replication, in two condition of non-stress and without drought stress were carried out. Three Diploid species, two kind of Tetraplepoloid and two kind of Hexaploid in the greenhouse of university Zabol, were examined in a pot. The evaluated physiological traits were included Proline, Glycine betaine, total Soluble Carbohydrate, total Protein, RWC (relative humidity). Also, the pattern of gene relative expression of Prolin (P5CS) and Glycinebetaine (BADH) expression was measured using Real Time PCR. Drought stress increased total Protein, total Soluble Carbohydrate, Proline, Glycinebetaine and significantly reduced relative water content, and drought stress induced expression of P5CS and BADH in all cultivars. Therefore, osmotic regulation and expression of two P5CS and BADH expressions under stress conditions can be used as an indicator in breeding programs to select drought tolerant cultivars.

The most common cause of diarrhea is Shigella and no vaccine has been found so far. IpaD and B subunit of Shiga toxin proteins (STxB) play an important role in invasion, infection and pathogenesis caused by Shigella. On the other hand, Co1 ligand has introduced as one of the antigen delivery systems to M-cells in mucosal layer. In this study, nasal administration of antigen in mice, used to evaluation and comparison of immunogenicity of IpaD, IpaD-STxB and IpaD-Co1 proteins. The coding sequences of proteins cloned in pET28a vector and transformed to bacterial strain of E.coli BL21(DE3). Recombinant protein expression confirmed by using of Western bloting technique. The each one of the recombinant protein purified by affinity chromatography column and used for nasal administration in four times consecutively on mice. After the second nasal administration (first booster), a week after each administration, blood samples were collected and ELISA performed on serum. The ELISA results of serum titration showed that the highest amount of IgG has been produced against IpaD-STxB protein; and IpaD-Co1 was in next step. The immunogenicity was evaluated using active toxin E. coli O157:H7. The challenge results showed that immunized mice could endure 5 times the LD50 Shiga toxin E. coli O157: H7; but after injection of 10 times the LD50, the immunized mice by IpaD, IpaD-Co1 and IpaD-STxB were death after 24, 24 and 72 hours, respectively. According to these results recombinant protein IpaD-STxB founded to be more immunogenic than IpaD-Co1 against shiga toxin in mice.

The aminoalcoholphosphotransferase is the key gene in the biosynthesis of phosphatidylcholine in Arabidopsis. Evaluating the effect of the second isoform of that gene, a T-DNA insertion mutant i.e. aapt2 was used. Comparison of aapt2 and wild type (WT) showed this line differs in the number of traits. There was a very significant difference between aapt2 and WT regarding the days that plant reach to two, three, four, five and six rosette leaves, final rosette size, 10% of flowers to be produced and flowering complete. For the days that plant reach to 8, 9, 10, 11,12 and 13 rosette leaves, first flower buds visible, first flower open, 30% and 50% of flowers to be produced and the first silique shattered; the significant difference between aapt2 and WT has been observed. There was no difference for the days that plant reach to 14 rosette leaves, rosette is 20, 50 and 70% of final size and senescence complete between aapt2 and WT. These likely suggested that the protein encoded by the AAPT2 plays a role in the early stages of Arabidopsis growth. Also, aapt2 and WT were very significantly different in osmotic pressure, but the relative content of water, chlorophyll a and b, carotenoids, peroxidation of membrane lipids, stomatal resistance and photochemical efficiency of photosystem II did not show any significant differences. Also, the aapt2 and WT were significantly different for leaf number and fresh and dry weight of leaves, however; the fresh and dry weight of root was not different.

In order to investigate the response mechanism to salinity stress in autumn rapeseed, Orient tolerant cultivar was evaluated in greenhouse condition and salinity stress began at the stem elongation stage and two weeks after stress, leaf samples were prepared. The results showed that salinity stress reduced the value of morphological and physiological traits, caused imbalance in ionic concentrations by increasing the concentration of sodium ion and decreasing intracellular potassium ion, as well as decreasing potassium/sodium ratio within leaf cells. Meanwhile, under salinity stress, the relative water content of the leaves decreased, but the concentration of proline and glycinebetaine was higher than that of control condition. Also, the results of the proteome analysis showed that among the control and treatment of severe salt stress in this cultivar, among 118 protein spots, 8 repeatable protein spots had a significant difference and also a significant induction factor. The function of the identified proteins in the studied cultivar were related to cell homeostasis, energy and carbohydrate metabolism, photo-reaction of photosynthesis, and transcription regulation (protein synthesis).

Wild relatives are valuable genetic source for wheat breeding programs. Triticum boeoticum is an important wild relative of wheat. Eastern and central parts of the Fertile Crescent are the origins of T. boeoticum. In the present study, the genetic diversity among 39 accessions of T. boeoticum collected from North and South areas of Zagros was investigated using ISSR and CBDP markers. ISSR and CBDP primers generated 230 and 65 scorable polymorphic bands respectively. According to ISSR and CBDP data, the average of genetic distance between genotypes were 0.36 and 0.40 respectively. Polymorphism information content for ISSR and CBDP primers ranged from 0.24 to 0.38 and 0.23 to 0.43 respectively. Cluster analysis based on combined(ISSR and CBDP) data using UPGMA method classified all accessions into two main groups, although two accessions(31,35) classified individually. This clustering was supported by principal coordinate analyses (PCoA). This classification was in accordance with their eco-geographical distribution. The results of AMOVA indicated that 94% of the molecular variance was partitioned within populations, while the genetic variation between populations was 6%. According to Shannon’s index(I), Nei’s genetic diversity(He), the observed(Na) and effective (Ne) number of alleles, the northern population had a higher level of genetic diversity than the southern population.The Results indicated a desirable genetic diversity in Triticum boeoticum and confirmed that the CBDP markers as well as ISSR markers are suitable tools for studying genetic diversity in wild relatives of wheat.

The flaxseed (Linum usitatissimum L) is recognized as an important crop and the rich source of useful fatty acids, protein, dietary fiber and lignans.Lignans as antioxidant compounds are an important group of secondary metabolites that have important biological activities, such as anti-cancer effects in humans. In this study, the expression of Phenylalanine ammonia lyase (PAL) and Cinnamyl alcohol dehydrogenase (CAD) genes in the lignan biosynthesis pathway were investigated under the influence of nano-ZnO and nano-TiO2 in flax cell culture. For this purpose, a factorial experiment in a completely randomized design with three replications were done to study the effects of of nano-ZnO and nano-TiO2. Nano-ZnO at 0, 30, 60 and 120 mg/L and nano-TiO2 at 0, 50, 100 and 150 mg/L were added to cell cultures and samples were collected at 0, 24, 48, and 72 h after adding nanoparticles. The gene expression analysis were studied using Real-Time PCR. The highest expression of PAL gene was observed at the concentrations of 30 and 60 mg/L, and the lowest expression was observed at the concentration of 120 mg/L of nano-ZnO. Nano-TiO2 had no significant effect on PAL gene expression, but the use of 150 mg/L nano-TiO2 led to increased expression of CAD at 48 and 72h. CAD expression increased at 60 mg/L concentration of nano ZnO at all intervals and the lowest expression of CAD was observed at 120 mg/L nano ZnO. The results of this study showed that zinc nanoparticles are effective in increasing the expression of both PAL and CAD genes, while the nano-TiO2 only affect the expression of CAD and has no effect on the expression of PAL expression.