Crop Biotechnology
Year:2015 | Volume:4 | Issue:8|Papers Count:6

Analysis of gene expression is considered as an essential part of functional genomics studies in all living organisms. Real-time PCR technique is very strong one to study the expression of a gene. However, despite its reliability, it has a set of specific problems, such as internal control gene selection which are suitable for normalization of the data. The study about selection reference of genes in sesame plant, at different developmental stages and under salinity stress of were studied. For this purpose, four internal control genes consists of eIF4- A, UBQ5, Alpha-Tubulin and Beta-Actin which are commonly used as housekeeping genes in plants, are selected and the stability of its expression in different salinity levels (zero and 75 mM) and different growth stages in five time periods (0 h, 6 h, 1 day, 4 days, 8 days and 16 days) in leaf tissue were examined. Study of the expression of reference genes using geNORM software showed that, in developmental stages and salinity in the leaf tissues, eIF4-A and Beta-Actin genes have more stable expression than other investigated genes. Using these genes can be useful in normalization of gene expression by Real-Time PCR analysis. The results can be used as reference genes for gene expression analysis in the Real-Time PCR.

Various abiotic stresses lead to the overproduction of reactive oxygen species (ROS) in plants and cause to damage to proteins, lipids, carbohydrates and DNA. Antioxidative enzymes such as catalase and ascorbate peroxidase are activated to protect the plants against oxidative stress. Silicon is the second most common element in soil that has beneficial effects in improving plants tolerance to drought stress. Accordingly, the effects of drought stress on semi-quantitative gene expression and enzymatic activities of both catalase and ascorbate peroxidase were investigated in two lines of two-row barley named CB-20315 (resistant) and CB- 20213 (sensitive) in tillering stage in a greenhouse. The experiment was performed in a completely randomized design with three replications for three treatments of control, drought and silicon-drought (sodium silicate 2 mg / 1 kg), and analyzed in factorial experiment. RTPCR semi-quantitative analysis revealed significant differences between treatments. The highest level of gene expression was observed for both enzymes in the silicon-drought treatment. The data showed that silicone application affect antioxidant enzymes activity to increase in both studied lines under drought stress. According to the results of this study it might be concluded that silicon participate in physiological.

Basil (Ocimum basilicum L.) is a member of a Lamiaceae family with aroma compounds and high essence. Furthermore, the essential oils of basil leaves are composed of phenylpropanoids, which have shown antibacterial and antioxidant properties. Phenylalanine ammonia Lyase is an important enzyme in phenylpropanoid pathway. The literature indicated that plant hormones affect gene expression in plants and increase the production of secondary metabolites. In addition, the hormones stimulate the immune system through transcriptional activation of defense related genes, and in turns, increase induced resistance of plants. In the current study, Real Time PCR was used to evaluate the gene expression and enzymatic activity of phenylalanine ammonia. The plants were treated with three different hormones including gibberellic acid, jasmonic acid, and salicylic acid with 0.1 mM/L concentration. The activities were studied during three different plant growth stages which included seedlings, pre-flowering stage, and flowering stage. The difference between gene expressions levels were analyzed by Duncan method (P£0.05) using SAS software (version 9.0). During the flowering stage, the results showed an increase in gene expression of phenylalanine ammonia Lyase in plants treated with jasmonic acid. The gene expression of phenylalanine ammonia Lyase was significantly higher (5%) for all treated samples compared to the control samples. The studied hormones increased the gene expression and enzymatic activity of phenylalanine ammonia Lyase.

Osmotic stress (such as drought stress) is a serious limiting factor to rice production and yield stability in worldwide. In order to locate the QTL associated with tolerance to osmotic stresses in germination stage and determine the contribution of each QTL on the phenotypic variation caused 96 lines of F8 Anbarboo ´ Sepeedrud (tolerant and sensitive to drought stress in germination stage, respectively) an experiment was conducted at Gonbad Kavous university in 2011-2013. For construction of genetic linkage map, 365 SSR marker and 32 primer combination were evaluated. 136 polymorphic SSR markers and 21 primer combination were used for providing of linkage map. Germination components including root length, shoot, coleoptile and the percentage of seed germination was recorded for 100 seed of each line in the osmotic stress resulting from sucrose, sorbitol and mannitol. For root length in all three stress conditions was found a QTL on chromosome 4 that had positive effect in all cases. Among the identified QTL, qSUC-5 (QTL for coleoptile length under sucrose stress) on chromosome 5, qSUR-2 (QTL for radicle length under sucrose stress) on chromosome 2 and qSUR-4 (QTL for radicle length under sucrose stress) on chromosome 4, respectively, 23, 23 and 26% of phenotypic variation for coleoptile and root length were justified in terms of osmotic stress. This QTL explained that due to the high percentage of candidates for marker-assisted selection programs recombinant line population of Iranian rice.

The plant bioreactors can be used for in vitro plant propagation and leading to a decrease in the costs of micro propagation. In this research, a simple bioreactor including a temporary immersion system was designed and made for Damask rose micro propagation. To optimize this system, the effects of the tube type, container size and different substrates were investigated in the independent experiments. Also, the temporary immersion system was compared with the solid and liquid media. Results showed that the highest number of the shoots in the temporary immersion system were obtained by the use of the white tube (11 shoots per explant), 600 ml glass container (10.36 shoots per explant) and without any substrate (10.76 shoots per explant). Also, temporary immersion system was significantly better than the solid and liquid media for shoot production (10.66, 2.56 and 5.66, respectively).

A core collection consists of a set of accessions selected to represent the genetic diversity of a base collection. This strategy was introduced with the intention of minimizing the cost of genetic resource conservation, while ensuring maximum genetic variation. It also allows a rapid evaluation of germplasm, and a better access to the base collection. In this study, One hundred and thirty-nine accessions of almond with diverse origins were used for evaluation of genetic diversity and core collection establishment using 32 simple sequence repeat loci and some quantitative and qualitative traits. A total of 252 alleles were detected, which average allelic richness was 7.75 alleles per locus. The model-based structure analysis here revealed the presence of five subpopulations in the base set, which was approximately consistent with clustering based on the genetic distance. Using a heuristic approach, a core set of 112 and 20 accessions was successfully developed using molecular and morphological traits respectively which showed 100% coverage of alleles with minimum redundancy. The results from molecular analyses did not correspond to morphological traits, hence to establish of core collection we have to study both morphological and molecular markers, simoltaneously. These results will provide an effective aid for future allele mining, association genetics, mapping and cloning gene (s), germplasm conservation, and promotion in breeding programs at future.