مجله زیست فناوری گیاهان زراعی
پیاپی 1 (پاییز و زمستان 1390)

Rice is an excellent model cereal for molecular biology and genetics research. Salinity is a major factor limiting rice production world wide. The analysis of stress-responsiveness in plants is an important route to the discovery of genes conferring stress tolerance and their use in breeding programs. To further understand the mechanism of plant response to salinity we employed a proteomic approach to profile the protein changes of rice 3th leaf and root under salt stress. Plants were grown in Yoshida nutrient solution and salt‏ stress imposed after 25 days. Plants were treated by 100¬‏mM NaCl for 10. After that 3th leaves and total root were collected from control and salt stressed plants. The Na+ and K+ content of leaves/roots and several yield components changed significantly in response to short-term salt stress and their proteome patterns were analyzed using 2-DE in triplicates. The expression pattern of proteins significantly changed in all leaves/roots in response to stress. More than 488 and 345 protein were detected repeatedly in root and leaf 2D‏gels respectively by software package. 107‏ proteins in root and 86 proteins in leaf of two genotypes showed significant response to stress. 3 protein in leaf gels and 2 protein in root gels were selected and identified by ESI-Q-TOF. The most important were Ferritin, Rubisco activase and ascorbat¬peroxidase in leaf and Peroxidase and Ascorbat¬peroxidase in root. All of them were enzyme and involved in detoxification and removal of reactive oxygen species (peroxidase, ascorbat¬peroxidase) Iron homeostasis (ferritin) or activation of other enzymes (rubisco¬activase).

The objective of this study was to improve induction of embryogenesis in bread wheat microspores. In this study, some F1 hybrids i.e M85-6 × 90, M85-8 × 90, mv17 × shiroudi, mv17 × kavir and kavir × bam were used. Microspores were cultured in A2 medium containing different amounts of maltose (60¬ & ¬90 ¬g/lit) depending on the genotype used. Analysis of variance for embryogenesis and regenerable embryos showed highly significant difference between hybrids but there was no significant difference between media (A2-60¬ &¬ A2-90) and interaction effects. M85-6 × 90, mv17 × Shiroudi and mv17 × kavir produced the highest ratio of embryogenesis among the hybrids. In regeneration phase, mv17 × Shiroudi and M85-6 × 90 had the highest frequency of regenerable embryos. The effect of 2,4-D as a novel stress for induction of microspores embryogenesis in Falat -known as the most responsive wheat cultivar to microspore culture technology, was investigated. Microspores were subjected to 2,4-D at 3 concentrations including 15, 25, 35 mg/l for 30 minutes while microspores without any stress treatment were used as the control. The embryogenesis of microspores stressed with 2,4-D were better than control. The highest yield of embryogenesis was produced at 15 mg/l 2,4-D. The most regenerated embryos were obtained in 15 & 25 mg/l of 2,4-D. According to the results obtained, 2,4-D is introduced as a new stress for induction of embryogenesis in microspores of wheat.

Protein phosphatase 2C family consists of a group of evolutionary conserved serine/threonine phosphatases which play a role in stress signal transduction. A subfamily of this Protein phosphatases in Arabidopsis, including ABI1 and ABI2, are known as components of ABA signal transduction pathway. Their mutants are hypersensitive to ABA showing increased expression during seed dormancy and adaptive responses to drought. Considering sensitivity of rice to abiotic stresses, particularly drought, identification of this gene family in rice and studying their role in response to stress would be beneficial. In this research, nine OsPP2C proteins were found in rice (OsPP2C1 to OsPP2C9), carrying all the conserved motifs of this subfamily. Among them, only OsPP2C5 transcript levels were significantly up-regulated by drought and abscisic acid which is down-regulated by re-watering or ABA removal. Drought stress induced OsPP2C5 gene expression in all the studied tissues. Based on RNA in situ hybridization experiments, OsPP2C5 transcripts were observed in almost all cells and accumulated more in the nuclei in divisional zone of the drought stressed peduncles. However, the transcripts of this gene were accumulated at higher level in the primary and secondary vascular bundles, phloem and xylem parenchyma, epidermal cells and sclerenchyma / chlorenchyma precursors. Based on the achieved results, it seems that OsPP2C5 gene is playing a role in ABA/ drought stress signal transduction. It is expected that appropriate genetic manipulations to this gene family would increase the tolerance to the abiotic stresses.

A system was designed using E. coli heat shock promoter (groE) in plastid vector and a hybrid plant/bacteria sigma factor was constructed under control of a tissue specific promoter. This system was designed for overcome to deleterious effects on plant growth and fertility that may be caused by transgene overexpression. So that hybrid sigma factors contained N- terminal motives of tobacco sigma factors including chloroplast signal peptide and RNA polymerase interaction domains, composed by C-terminal motif of E. coli sigma32 that able to recognition and binding to groE promoter. Then this gene, HSig, was cloned in Agrobacterium vector after adding regulatory elements. The result vector was used for transformation of an Iranian variety of tobacco. Detection of transgenic plants was performed by PCR, southern blot and RT-PCR analysis. The Hsig gene expression and its targeting to plastid was confirmed after transformation of tobacco chloroplast using gene gun technique for targeting of green florescent protein (GFP) under control of groE promoter using pFNGi vector into transgenic HSig explants. We hope that the system that was designed and constructed in this study for GFP expression in chloroplast genome, be able to apply in molecular farming for expression of any other desired genes instead of GFP for specific gene expression in chloroplast.

This research was conducted to validate and fine map the region attributed to salinity tolerance on chromosome1 in rice (Saltol) at International Rice Research Institute (IRRI) during 2005 to 2007. A major effect QTL (Saltol) which is responsible for Na+ and K+ uptake and their ratio was identified using F8 recombinant inbred lines (RILs) of Pokkali/ IR29 cross on chromosome 1. This QTL explained around 64.3 to 80.2% of the phenotypic variation for the mentioned traits. Fine mapping was done using 10 SSR and EST-SSR markers and near isogenic lines (BC3F4), derived from IR29 × Pokkali that were produced for this trait. Random BC3F4 individuals were genotyped and phenotyped under two different electrical conductivities at seedling stage. QTL responsible for salinity tolerance at both ECs, were found in the same place in Saltol region, which explained 18 and 24% of the phenotypic variation for SES scores, respectively. According to the present results, possible location of Saltol was found in the interval around 1.2 cM on chromosome 1 that could physical map. It was around 350Kb. This QTL was mapped at the intervals of RM8094, RM3412 and CP6224. Therefore, molecular breeding for salinity tolerance in Iranian genotypes could be done using the mentioned markers.

Commonly, plant roots colonized by arbuscular mycorrhizal fungi (AMF) can tolerate different stresses such as soil salinity. Thereby, identification of the dominant AMF species in the saline soils and their application as biofertilizer is very useful for increasing crop productivity in such conditions. For this purpose, sampling was performed from root and rhizosphere of wheat, barley and weeds in Yazd, East Azerbaijan, Qom and Markazi provinces. The morphological properties of spores of the isolated AMFs were studied. Then, samples were screened using a two steps nested PCR methodology. At the first step, AMF-specific primers, including LSU-Glom1 and SSU-Glom1 were used, followed by Alu1 restriction of PCR products, and then at the second step, the restricted PCR products were amplified by fungal universal primers (ITS4 and ITS5) for amplification of ITS-rDNA region. The PCR products were cloned, and restricted by Taq 1. The results of morphological charectreristics and analysis of the achived sequences and blasting showed that two AMF genus, including Glomus (more than 90%) and Acaulospora (10%) were domininat. The species G. mosseae (50%), G. intraradices, G. sinosum, G. constrictum, G. etunicatum, G. versiforme, G. fulvom, and Glomus sp were identified using molecular strategy. The maximum species diversity was observed in the fields of Yazd Province and rhizosphere of wheat. Totaly, results of the present study showed that the species G. mosseae has the highest dominancy and adaptivity in saline conditions, so after performing further experiments, it can be used as a source of biofertilizer in such regions.

Several sources of cytoplasmic male sterility (CMS) have been described in beets. Sugar beet cultivars are producing only using the source of Owen CMS. Introducing Owen CMS from cultivated sugar beet, have been important role in development of hybrid cultivars and changed breeding methods in sugar beet. Sugar beet cultivars carring CMS Owen are semi fertile. In order to investigating cytoplasm variation and cytoplasmic male sterility source between cultivars, mitochondrial minisatellite and PCR-RFLP markers were used. Banding profiles of four cultivars and two male strile and fertile lines demonstrated the presence of Owen CMS in breeding process of these cultivars. Cytoplasmic variation was not observed between cultivars, but some progeny of cross between cultivar plants and a pollinator were sterile. It seems, other resource, besides Owen CMS have been used in producing some hybrid cultivars.

Fourteen populations of Sections Hymenobrychis, Lophobrychis and Onobrychis of sainfoin were collected from natural habitats across Iran. Number and size of chromosomes as well as karyotypic formula of the populations were measured and studied using their root tip meristemes. The basic chromosome number varied between x=7 and x=8 and their chromosomal types were metacentric and sub-metacentric. According to average of genoms length, the highest belonged to O. viciaefolia (48.157µm) and the lowest to O. amoana subsp. meshhedensis (14.409µm). The results of analysis of variance based on unbalanced completely randomized design showed significant differences among the populations for the most of the studied traits (P<%1). O. michauxii2 classified as asymmetric class of B and others as A. O. amoena subsp. meshhedensis with 14m formula, stand in A class, had the most relative length of shortest chromosome(68.26), lowest intra chromosal asymmetrical(0.12) lowest differences of relative length(5.31) and the highest total form percentage was symmetrical species. Using principal components analysis, the first two components justified %97.94 of total variance. By cutting dendrogram, resulted from cluster analysis based on the karyptipic parameters species, the highest distance was obtained between O. schahuensis 1 and O. viciaefolia and the lowest metric distance value was obtained between populations of O. schahuensis 1 and O. chorassanica 1.