Co-Authors:
Solomon, A., Department of Animal Sciences, Faculty of Agricultural, Food and Environmental Quality Sciences, Hebrew University of Jerusalem, Rehovot 76100, Israel, Department of Biochemistry, Molecular Biology and Cell Biology, 2153 North Campus Drive, Evanston, IL 60208-3500, United States
Salomon, R., Department of Virology, ARO, Volcani Center, Bet Dagan, 50250, Israel
Paperna, I., Department of Animal Sciences, Faculty of Agricultural, Food and Environmental Quality Sciences, Hebrew University of Jerusalem, Rehovot 76100, Israel
Glazer, I., Department of Nematology, ARO, Volcani Center, Bet Dagan, 50250, Israel
Abstract:
The present study describes a novel heat-stable, water-stress-related protein with a molecular mass of 47 kDa (designated Desc47) in the entomopathogenic nematode Steinernema feltiae (IS-6). The protein was accumulated about 10-fold (from 7.84 ± 1.85 to 74.09 ± 4.35 % relative content level [RCL]) in dehydrated clumps of infective juveniles (IJs), which had lost 34-4 % of their initial water content (from 65.1 ± 1-7 % to 42.7 ± 0.72 %) in a desiccation-tolerance-inducing treatment (97 % relative humidity [RH] for 3 days). The appearance of Desc47 was accompanied by trehalose accumulation (from 300 to 600 mg trehalose/g protein) during the process of inducing the IJs into a quiescent anhydrobiotic state. A second cycle of IJ dehydration did not alter the RCL of Desc47 (79.3 % for the first cycle and 73.3 % for the second cycle). Desc47 retained its high RCL (69.7 %) in rehydrated active IJs for 3 days, reaching 51.2 % of its initial RCL only after a week. No homology to other known proteins was found by mass-spectrometry electrospray-ion-trap analysis. However, of the 5 sequences obtained from the protein (ranging from 11 to 21 amino acids), the 21-amino-acid peptide N V A S D A V E T V G N A A G Q A G (D/T) A V showed excellent homology (74% identity in 19 amino acids) to the cold-responsive protein COR14b (g6564861) from Triticum aestivum. In the Caenorhabditis elegans predicted proteome database search, the N21 yielded the first-best identity score (59 % identity in 17 amino acids) to the CE-LEA homologue protein (g2353333). In plants, COR and LEA are related proteins, heat-stable, which are expressed in response to both dehydration and cold acclimation. The implication of the involvement of Desc47 and the osmoprotectant trehalose in the desiccation-tolerance mechanisms of S. feltiae is discussed.