مجله زیست فناوری گیاهان زراعی
پیاپی 27 (پاییز 1398)

Wheat streak mosaic virus (WSMV) is one of the most important wheat infectious which its prevalence is increasing in Iran. NIa protein as a key protein in WSMV, plays important roles in viral replication and proteolytic digestion of viral polyprotein. Considering the critical role of NIa protein in viral infection, isolation, sequencing and determination of secondary and tertiary structure of this protein were the objectives of the present study. Also, the amino acids present in the NIa protein active site, which can be used as the targets for design and developement of new antiviral agents, were investigated. In this study, the gene encoding NIa protein was isolated from WSMV and its sequencing was done followed by cloning in pEST prokaryotic vector. The resulted nucleotide sequence was deposited in NCBI database with accession number MK335432. Investigation of physical and chemical properties showed that NIa protein is including 426 amino acids, 48.8 kD molecular weight and 8.81 PI. Prediction of secondary structure of NIa protein revealed that 53.29% of its structure composed of irregular loops, which was justified by the structural dirsorder of this protein. The results of the active site investigation of NIa protein based on homologous sequences alignment and three-dimensional structure of the protein showed a highly conserved site which was included of histidine, aspartic acid and cysteine amino acids.

Iron toxicity lead to increasing of free oxygen radicals, oxidative stresses and sever yield reduction of Rice. One of the plant responses for physiochemical and biochemical regulation to stresses is change of antioxidant enzyme contents. In this study the effect of five treatments of iron (Fe-EDTA) (0, 100, 250, 400 and 500 mg/li-1) on relative expression of glutaredoxin (GRX), thioredoxin (TRX), peroxiredoxin (PRX) and catalase (CAT) genes of IR64 (susceptible) and Pokkali (tolerant) genotypes of Rice in Yoshida hydroponic media by Real time-PCR technique investigated. The results showed that the relative expression level of CAT gene in different levels of iron in Pokkali genotype was higher than IR64 genotype. The relative expression level of PRX in IR64 genotype in all of the levels was similar. The relative expression level of TRX in Pokkali genotype was not significant. The relative expression level of GRX in the most of stress levels in Pokkali genotype was higher than IR64 genotype. Low level iron result in increasing of relative expression level of CAT, GRX and TRX in IR64 genotype. But with increasing level of iron was not significant change in expression of genes. Also in the most of the iron level relative expression of genes in Pokkali was higher than IR64. Probably lose of change in gene expression levels in high level iron and low gene expression in IR64 is one of the reasons of its susceptibility to iron stress.

Yellowing diseases of field and greenhouse-grown cucurbits caused by whitefly-transmitted viruses are increasingly becoming important and cause economic losses in many cucurbits growing areas of the world. In this research, 195 samples with symptoms yellowing, stunting and deformation of leaves were collected from fields of cucurbits in the South-East Iran (Sistan and Baluchestan). In order to detect CVYV and CYSDV, cDNAs were prepared using Random Hexamer primer and total RNAs extracted from the collected samples.Then, Polymerase Chain Reaction (PCR) was performed using exteracted RNA and specific primers (CYSCPf and CYSCPr for CYSDV, CV+ and CV- for CVYV). The results revealed that a 450 bp fragment from the CVYV-CP and a 700 bp fragment from CYSDV-CP were amplified from 55 and 17 samples, respectively. About 7% of the samples had simultaneous contamination with the two viruses. Based on the Phylogenetic studies CVYV were divided into two main groups I (subgroups IA and IB) and II: the first group belongs of isolates from Lebanon and Jordan, Tunisia and Spain, but the second group contained only isolates of Iran (Chabahar) which indicates the high diversity of this isolate. The results of the genetic diversity and selection indices showed that the gene flow from Europe to Asia is very small and the genetic difference is high between them. The CP region is under severe pressure a negative choice, and has caused variation and evolution of the CVYV. Generally, based on the results, the most diversity molecular and host are in Asia group.

Rapeseed (Brassica napus) is one of the most important oil plants in the world. Not only it has rich sources of fatty acids, but also contains protein. Cold stress is one of the growth limiting factors for this plant, which causes massive molecular changes inside the plant. In this research miRNAs, bna-miR164a, bra-miR5712, bra-miR5717, bna-miR6029, bna-miR6035, bna-N_miR2, bna-N_miR16 that previously had been studied separately in cold and fatty acid biosynthesis, were selected for investigation of the relationship between microRNAs, Cold stress, Fatty Acids and Lipids. Afterwards, bioinformatics prediction of target genes, investigation of gene ontology and their functional pathway and mapping of protein interactions network were performed. As a result, it was discovered that miRNAs which are effective in cold stress, beside regulation of target genes such as SCRM2, HOS1, STZ, GLP4, PP2CA, which are responsible for cold response and thermal stimulus-response, also have regulatory roles on other target genes such as KAS2, FAD8, FAD4, AAD3, FAD7, FAD2 which are involved in biological processes such as unsaturated fatty acid biosynthesis, unsaturated fatty acid metabolism, fatty acid biosynthesis, fatty acid metabolism, cellular lipid catabolism and lipid metabolism, lipid biosynthesis, cellular lipid metabolism. Evaluation of Protein-Protein Interactions revealed that there was a relation between the target genes involved in fatty acid biosynthesis and the target genes involved in cold stress. The next step for subsequent research is to investigate the expression of these miRNAs and their target genes during cold stress and further experimental verifications to prove the regulatory relationship between them.

Study of stress tolerance in barley can help for a better understanding of the genetic basis of drought stress tolerance mechanisms and lead to improve the genetic properties associated with drought tolerance through modern molecular genetic techniques. To this end, microRNAs associated with drought stress in barley leaf and root ESTs were analyzed in Nimruz and spantaneum barley genotypes. Bioinformatics databases were mined for relevant EST libraries and bioinformatics services were used for pre-processing and identify genes with different expressions among libraries. The expression profile of candidate genes was studied, by using Real time-PCR in a factorial-split plot design, including Nimruz as tolerant and Spontaneum as a drought sensitive in pots with three replications. Sampling time was also considered at 0, 24 and 72 hours after drought stress as sub factor. Results of this study led to identification of three highly-expressed miRNAs (ath-miR414, os-miR2102-5p and osa-miR414). The expression analysis showed that miR414 and miR2102 expression was significantly (P< 0.05) increased in both genotypes in response to drought stress. After 72h in Nimruz and Spontaneum, the expression of miR414 reached 2.61 and 2-fold and the expression of miR2102 was 2.4 and 2.8-fold of that of control (Spontaneum at control condition at 0 times), respectively.

Soybean is considered as one of the best source of protein for the nutrition of humans and mammals, and also is cultivated as an economic source of both vegetable oil and protein. Soybean like other Leguminosae, contains low levels of S-amino acids (methionine and cysteine). Using an appropriate selectable marker can be effective in the regeneration of transgenic plants and increasing gene transfer rate. Glyphosate is a widely used non-selective herbicide with broad spectrum of weed control around the world. The aim of this study is constructing of two-genes construct consists of 11 kDa delta zein and EPSPS genes to improve the methionine content and induce resistance to glyphosate herbicide using Agrobacterium-mediated method in soybean. After experimental processes tissue culture, gene transformation and regeneration, plants produced by gene transformation showed glyphosate resistance at 3.5 mM concentration of glyphosate herbicide. Chlorophyll and shikimic acid content analysis also revealed that these two indexes in lines produce by gene transformation compared to wild type were significantly altered after glyphosate application. Complementary analyses are under progress.