MODERN GENETICS JOURNAL (MGJ)
Year:2011 | Volume:6 | Issue:1 (24)|Papers Count:11

Abiotic Stresses are one of the most important reasons of the reduction in crop production. As plants are sessile, for keeping their stability under stresses they show different molecular, biochemical and physiological responses to the environment. Heat Shock Proteins (HSPs) are one of the most important responses to the abiotic stresses which are responsible for protein folding, assembly, translocation and degradation in many normal cellular processes and also can play a crucial role in protecting plant cellular homeostasis against stress. Moreover, HSPs have some interactions with other response mechanisms (such as osmolytes). Here, we summarized the significance of HSPs and chaperones in abiotic stress responses in plants, and discuss the cooperation among their different classes and their interactions with other stress induced components.

Potato virus Y (PVY), Potato virus X (PVX), Potato virus S (PVS) and Potato leaf roll virus (PLRV), are the most important viruses of potato and can cause serious diseases and significantly reduce the yield and quality of potato crops. The incidence of these viruses is reported from almost all main potato growing regions in Iran. Therefore, application of a sensitive, rapid and inexpensive procedure for simultaneous detection of potato viruses is very important for management of their control. In the present research, a sensitive and reliable multiplex RT-PCR technique for the detection of PVY, PVX, PVS, PLRV and 18S rRNA as internal control was employed and compared with ELISA, the method used routinely to assay potatoes for virus infections. Total RNA was extracted from virus infected potato leaves. Then cDNA for above viruses and 18S rRNA was individually synthesized using their specific reverse primers and single RT-PCR for each virus and 18S rRNA. Subsequently, multiplex RT-PCR was carried out with five primer pairs in a single reaction. As a result, five different fragments (145-342 bp) specific to the viruses and the internal control were simultaneously amplified and were identified on the basis of their molecular sizes. The sensitivity of our optimized system also was compared with that of commercial DAS-ELISA for detection of PVY, PVS and PLRV. The results showed that the sensitivity of multiplex RT-PCR was 100-fold greater for detection of PVY, PVS and PLRV and the duplex RT-PCR was 1000-fold greater for detection of PVY than that of commercial DASELISA.

Iranian wheat stripe virus (IWSV) is a tentative member of the genus Tenuivirus. The coat and nonstructural proteins (CP and NS4, respectively) are the most common proteins of tenuiviruses encoded by the vcRNA3 and vRNA4 segments, respectively. The specific antibodies against those proteins can be used for detection of the viruses and investigation of functions of the related genes. To express CP and NS4 of IWSV, the related genes were amplified using specific primers and cloned into the expression vector pET 28a. Recombinant plasmids were used to transform Escherichia coli strain BL21 (DE3). The transformed bacteria were cultured in IPTG-induced media. SDS-polyacrylamide gel electrophoresis showed two bands with molecular weights 40.9 and 23 kDa which corresponded to the molecular weight of the putative products of the related genes in tenuiviruses. The expression of target proteins was confirmed using specific polyclonal antibodies by western blot analysis. The large-scale production of highly purified proteins by a microbial system represents pure antigen free from the contaminating plant materials that can be used to produce the related antibodies.

In this study, association of agronomic traits and molecular markers in barely was studied using 115 landraces and 70 SSR markers. These markers were produced using 10 primer pairs, where PIC values for primers ranged from 0.31 to 0.85. AF220725A, Bmag0013 and HVM40 primers with the maximum PIC values showed higher polymorphic index, indicating that these markers display the genetic distance of varieties better than other markers. By multiple regression method (stepwise) relationship of each 10 agronomy traits and the 70 polymorphic markers were studied. HVM20, Gms003, Bmac0306 and HvHVA1 primers, explained more variation of the traits compared to other primers. Moreover, our results showed that some of the markers were related to more than one trait, implying close linkage and/or peliotropy of these traits on chromosomes. However, for better understanding of these relationships, preparation of segregating population and linkage mapping is necessary.

A large number of marker protocols that are rapid and require only small quantities of DNA have been developed. Sampling was carried out on 120 Holstein cattle from 4 herds in Kerman city and 80 native cattle from 5 herds in Bam city. Both ISSR primers tested, (AG)9C and (GA)9C, produced many different bands. Based on results of this study, ISSR markers produce numerous comparable bands and ISSR fingerprinting patterns are highly heritable. Polymorphisms were abundant among 9 herds tested with these primers, (AG)9C primer gives the more informative profiles than (GA)9C and comparison of ISSR profiles can be successfully applied to study difference in intra and interpolations of cattle. Mean of gene diversity for (AG)9C marker in native and Holstein herds was 0.57 and 0.28 and for (GA)9C marker was 0.35 and 0.15 respectively. Mean of polymorphic loci number and mean of polymorphic percentage in any population based on (AG)9C marker for native herds were 15.60 and 44.65 and for Holstein herds were 17.75 and 54.29 respectively and based on (GA)9C marker for native herds were 8.40 and 70.01 and for Holstein herds were 10.25 and 85.42 respectively. The highest of polymorphic percentage based on (AG)9C marker in Holstein and native herds was 74.29% and 65.71% and based on (GA)9C marker was 100% and 91.70% respectively. Thus, ISSR markers are a good choice for DNA fingerprinting of cattle.

Ten genotypes including six F1 progenies and their parents were grown in Kashmar Cotton Research Station in two separate experiments (non-stress and drought stress conditions), in a randomized complete block design with three replications. Diallel analysis was done based on Griffing’s method II for seed cotton yield, boll seed cotton weight, percentage of earliness, the number of bolls and height of plant. Results showed that the variance of genotypes was significant for boll seed cotton weight and height of plant in non-stress environment and for seed cotton yield and height of plant in stress condition. The effect of general combining ability of boll seed cotton weight and height of plant were significant in non-stress environment. Also it was significant for seed cotton yield and height of plant in drought condition. The effect of specific combining ability wasn’t significant for any trait. Diallel analysis showed that additive gene effect had an important role in controlling the mentioned traits. Combined diallel analysis indicated that additive variance was important for seed cotton yield and height of plant. Broad sense heritability was high for all traits in both conditions, whereas narrow sense heritability varied from low to high in both conditions.

In recent years, symptom of psorosis on stem oak leaf pattern on citrus trees leaf appeared in Gorgan areas. In order to identify of causal agent (Citrus psorosis virus), sampling was done from infected orchard of Gorgan area during 2006-2007. Sampling was done from all of citrus cultivars in this area including sweet orange (Yafa, Washengton novel, Sunkin and Tompson) and Mandarin (Clemantin) frome suspicious trees to infection that has shown psorosis diseases symptoms. Serological test was done via DAS-ELISA using of monoclonal antibody of CPsV and RT-PCR test was done via specific primer of CPV1 and CPV2 that designed from coat protein gene cod area of CPV on 200 samples was collected from Gorgan area orchards and six samples from Citrus Research Center (Ramsar) scientific glasshouse that show specific glasshouse that showed specifice Symptoms in Biological Indexing. DAS-ELISA tests did not show any infection by using CPsV monoclonal Antibody (AgritestsÒ, Italy). The primers (CPV1 and CPV2) were produced on a 600 bp cloned fragment of CPsV coat protein gene. Laboratory tests showed an infection of 7.5% samples commercial groves and the all samples from Citrus Research Center (Ramsar) scientific glasshouse. No relationship was observed between the commercial CPsV monoclonal antibody and CPsV infection. However, results showed that the best RNA extraction method is the guanidine buffer. This is the first report of CPsV occurrence in Golestan province.

To reduce the effect of genotype × environment interaction and perform more accurate selection, performance and stability of genotypes should be considered simultaneously. In this study we used parametric and nonparametric methods to determine stable genotypes and the correlation between these methods was discussed. Ten lentil (Lens culinaris Medikus) genotypes in five regions of Iran (Gachsaran, Kermanshah, Shirvan, Gonbad and Ilam) were evaluated for yield stability within two years (2003-2004). Based on stability analysis by methods of Eberhart and Russel, Lin and Binns, Wricke Ecovalence and coefficient of determination of Pinthus introduced, genotypes of (9, 6), (5, 9), (8, 9) and (9, 8) were identified as the most stable ones, respectively. Results of analysis of Thennarasu and Nassar and Huhn non parametric statistics showed that genotypes of (9, 8), (9, 8, 1), (8, 9), (2, 1) and (1, 2) were identified as stable genotypes were stable genotypes, respectively. Finally by the correlation between parametric and nonparametric methods, genotype 9 (ILL 6199) was selected as a stable genotype. Results of this research showed that If the goal is to determine general compatibility, Shukla variance and Mean of Squares of Lin and Binns parametric statistics and NP(1) and NP(3) Tennarasu and Si(2) Nassar and Huhn nonparametric statistics are more proper than other statistics that studied in this research.

Environmental stresses such as drought and salinity cause to reduce productivity of crops down to 50%. Harmful effects of salinity stress involve, derangement in membranes activity, increase of toxic metabolites, prevention of mineral element uptake and photosynthesis, producing Reactive oxygen species (ROS) and finally, cells and whole plant dead. In this study, effects of short term salinity stress on proteome pattern of bread wheat leaf (Triticum aestivum L.) were examined. Seeds of the two varieties of wheat; salt resistant (Roshan variety) and salt sensitive (Falat variety), planted in a greenhouse and at the tilling stage, plants were exposed to 100 and 200 mM NaCl solutions. The samplings were done after 3, 6, 12 and 24 h of stress treatment by removing seedling leaves. Proteins extracted from wheat leaves were separated by two-dimensional gel electrophoresis. Result of analysis using Melanie software showed that, 86 spots in resistant variety significantly different from control and in this variety 78% of proteins had up expression and 13.5% had down expression. In sensitive variety 94 spots significantly different from control. In this variety 25% of proteins had up expression and 58.5% had down expression. Our results showed that the increasing of protein expression was corresponded with genes that responded to salinity.

Systemic Acquired Resistance (SAR) is a kind of plant resistance response to systemic viral infections. In this study the expression levels of factors that are responsible for hypersensitive response to TMV infection and factors that are involve in SAR resistant response to PVYo infection was studied. For that, we used non transformed N. tabacum cv. Samsun NN and susceptible transgenic tobacco plants in which theRDR6, mRNA transcript levels was low in the cells. Toward this aim quantitative expression of resistance key genes includingERF5, AOX1 and IVR were assessed by semi-quantitative RT-PCR method. The salicylic acid biosynthesis and its concentration within viral treated leaf tissues were evaluated by using salicylic acid reporter bacteria Acinetobacter sp. ADP1. The expression of PR-1 protein within inoculated plants was also assessed by western blott analysis. The peroxidase enzyme specific activity was evaluated. These results indicate, that SAR resistance response may be activated in response to the bio trophic stresses like PVY systemic infection in plants. This activation is not exclusive for early expression of key SAR factors but also it is need for expression of the key genes responsible in SAR signaling pathway. These results indicate thatRDR6 may be a key gene in SAR signaling cascade within plant cells in which its impairment can disturb the SAR inhibitory effects in PVY infected plants. Due to non-effective function of dominant single resistant genes for making resistance plants to PVY infection, it is suggested to use recessive resistance genes for development of PVY resistant transgenic plants in which the systemic acquired resistance pathways are active.