engleski

Proteomic analysis of the response of Mammillaria gracilis in vitro-grown tissues to iso-osmotic NaCl and mannitol

The plant response to abiotic stress often occurs as a consequence of protein expression change. In this study we have analyzed the effect of 250 mM NaCl and 500 mM mannitol on proteomes of in vitro-grown Mammillaria gracilis callus and tumour tissues. In callus qualitative or quantitative differences in protein expression was revealed for 37 protein spots, out of which 18 were identified and classified into 6 categories according to their putative physiological functions (protein synthesis and processing, energy, metabolism, oxidation and detoxification, disease and defence, and unknown proteins). By calculating the relative proportions, it was found that the most abundant category was protein synthesis and processing, in which 60% of proteins showed changes in expression due to NaCl treatment and were mostly up-regulated. When all categories were taken together it was obvious that majority of the callus proteins were up-regulated (78%) and mannitol-responsive (61%). In tumour 57 differentially expressed proteins were revealed, out of which 35 were identified and classified into 7 functional categories, including previously mentioned categories and one additional, cell structure. The most abundant category was metabolism (54.29%), in which approximately two thirds of the proteins were down-regulated as a result of either NaCl or mannitol treatment. From the analysis of all categories taken together it can be deduced that majority of the tumour proteins were down-regulated (68%) but similarly responsive to either NaCl (49%) or mannitol (51%). Obtained results indicate that mechanisms that mediate responses to saltand mannitol-induced osmotic stresses are dependent on tissue type.

proteomics ; salinity ; osmotic stress ; cactus

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