Proteome Changes in Stem Tissues of Sunflower Lines Inoculated with Culture Filtrate of Sclerotinia sclerotiorum.

BACKGROUND: Sclerotinia sclerotiorum (Lib.) de Bary cause a deleterious disease on sunflower plants. Oxalic acid is the main pathogenicity factor of S. sclerotiorum. Two dimensional gel electrophoresis and mass spectrometry have been used in several studies to investigate molecular changes that occur in the plants in response to S. sclerotiorum infection. Comparing responses of resistant and susceptible lines upon pathogen infection provided novel information regarding defense mechanisms against this necrotrophic pathogen. OBJECTIVES: The present study reports proteome changes of partially resistant and susceptible sunflower lines under pathogen's culture filtrate treatment, resulting in the characterization of up- and down- regulated proteins. MATERIAL AND METHODS: Sunflower partially resistant and susceptible lines with two true leaves were exposed to fungus culture filtrate. The stems of treated and untreated plants were sampled at 24, 48 and 72 hours after treatment for two-dimensional electrophoresis. Twenty spots showed more than 1.5-fold change in abundance were subjected to MALDI/TOF-TOF MS for further analysis. RESULTS: The identified proteins were categorized into several classes including carbohydrate and energy metabolism (25%), cellular metabolic process (15%), stress response (15%), plant cell wall biogenesis (10%), photosynthesis (10%), protein metabolism (10%), unknown function (10%) and redox homeostasis (5%). CONCLUSIONS: Our proteomic investigation demonstrates an increase in the expression of proteins only in partially resistant line, such as proteins involved in carbohydrate metabolism and plant defense responses (malate dehydrogenase and peroxidase), metabolic process (adenosine kinase), regulating cell redox homeostasis (disulfide isomerase) and lignin biosynthetic process (laccase). Moreover, the expression of pyrroline-5-carboxylate reductase, involved in proline biosynthesis, was significantly changed in both sunflower lines in response to pathogen culture filtrate. Proteins which were only up-regulated in the partially resistant lines might have a significant role in mediating the defense against Sclerotinia and could be considered for enhancing resistance against this devastating pathogen.

Phenological, morpho-physiological and proteomic responses of Triticum boeoticum to drought stress.

Drought is the most important abiotic stress limiting wheat production worldwide. Triticum boeoticum, as wild wheat, is a rich gene pool for breeding for drought stress tolerance. In this study, to identify the most drought-tolerant and susceptible genotypes, ten T. boeoticum accessions were evaluated under non-stress and drought-stress conditions for two years. Among the studied traits, water-use efficiency (WUE) was suggested as the most important trait to identify drought-tolerant genotypes. According to the desirable and undesirable areas of the bi-plot, Tb5 and Tb6 genotypes were less and more affected by drought stress, respectively. Therefore, their flag-leaves proteins were used for two-dimensional gel electrophoresis. While, Tb5 contained a high amount of yield, yield components, and WUE, Tb6 had higher levels of water use, phenological related traits, and root related characters. Of the 235 spots found in the studied accessions, 14 spots (11 and 3 spots of Tb5 and Tb6, respectively) were selected for sequencing. Of these 14 spots, 9 and 5 spots were upregulated and downregulated, respectively. The identified proteins were grouped into six functional protein clusters, which were mainly involved in photosynthesis (36%), carbohydrate metabolism (29%), chaperone (7%), oxidation and reduction (7%), lipid metabolism and biological properties of the membrane (7%) and unknown function (14%). We report for the first time that MICP, in the group of lipid metabolism proteins, was significantly changed into wild wheat in response to drought stress. Maybe, the present-identified proteins could play an important role to understand the molecular pathways of wheat drought tolerance. We believe comparing and evaluating the similarity-identified proteins of T. boeoticum with the previously identified proteins of Aegilops tauschii, can provide a new direction to improve wheat tolerance to drought stress.

Peganum harmala L.'s anti-growth effect on a breast cancer cell line.

This research was done to evaluate the induction of apoptosis in MDA-MB-231 breast cancer cell line by Peganum harmala's extract, in which a significant amount of ß-carbolines is included. The apoptosis incidence was assessed through Annexin-V-Flous kit. The expressions of genes through which intrinsic apoptosis pathway are involved, Bax, Bcl-2, Bid, and Puma, over the genes the expressions of which are linked to extrinsic apoptosis pathway, TRAIL, Caspase8, p21, and p53, were examined by RT-PCR and Real-time PCR. The results demonstrate that the extract decreases the growth rate of the cancer cell line through inducing apoptosis mechanism. As long as the expression of anti-apoptosis Bcl-2 gen reduced dramatically, an over-expression in Bax and Puma genes was monitored indicating activation of intrinsic apoptosis pathway. A notable over-expression observed with TRAIL and Caspase8 genes as well as Bid gene. The latter is an intermediate for both intrinsic and extrinsic pathways of apoptosis.