Polyploidy is a prominent process in higher plants and is often described as a genomic shock that may induce stress and defense responses. The Brassica napus allotetraploid model was chosen to investigate the proteomic modifications that occur during allopolyploid formation. Large-scale analysis of the proteome from the leaves of B. napus was performed and compared with the homozygous diploid progenitors, Brassica rapa and Brassica oleracea, and among the proteomic changes in B. napus in the early generations (F 1 -F 4 ). The abundance of all these differentially expressed proteins in the F 1 generation differed from that of the corresponding proteins expressed in its progenitors, some of which relatively deviated from mid-parent predictions, exhibiting somewhat non-additive expression repatterning. Proteomic changes in the resynthesized B. napus from the first to the fourth generations were detected, which indicated that gene silencing was a permanent phenomenon and it could be reactivated at any moment. Although leaf proteins were extensively modified in synthetic B. napus, the distribution of the "housekeeping" proteins was not disturbed. Moreover, no evidence of chaos or large disorder was observed after the merging of the two genomes. Instead, a novel order quickly developed, which might evolve in further generations of synthetic B. napus.

Embryogenic callus of Phalaenopsis amabilis derived from leaf tissue was cocultivated with Agrobacterium tumefaciens strain LBA4404 harboring a plant cloning vector. The vector carried the lipid transfer protein (LTP) encoding gene cloned from cold tolerant Brazilian upland rice cv. IAPAR 9. The highest transformation efficiency (12.16%) was obtained when 1-2 mm calli were infected and cocultivated with 0.4 (OD 600 ) A. tumefaciens for 20 min. Transgene integration of kan-resistant plants was confirmed through polymerase chain reaction analysis and Southern hybridization. Four hundred seventy transgenic plants, each derived from an independent protocorm-like body, were obtained. The expression of rice cold-inducible LTP gene in transgenic P. amabilis improved its adaptive responses to cold stress. The examination of transgenic plants revealed that enhanced cold tolerance was most likely due to the increased accumulation of several compatible solutes such as total soluble sugars, proline, antioxidant superoxide dismutase, decreased accumulation of malondialdehyde, and maintained electrolytes within the membrane compared with controls.

Salt stress is one of the major abiotic stresses in agricultural plants worldwide . We used proteomics to analyze the differential expression of proteins in transgenic OsNAS1 and non-transformant Brassica napus treated with 20 mmol/L Na 2 CO 3 . Total protein from the leaves was extracted and separated through a high-resolution and highly repetitive two-dimensional electrophoresis (2-DE) technology system. Twelve protein spots were reproducibly observed to be upregulated by more than 2-fold between transgenic and non-transformant B. napus. These 12 spots were digested in-gel with trypsin and characterized by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) to obtain the peptide mass fingerprints. Protein database searching revealed that 5 of these proteins are involved in salt tolerance: dehydrogenase, glutathione S-transferase, peroxidase, 20S proteasome beta subunit, and ribulose-1,5-bisphosphate carboxylase/oxygenase. The potential functions of these identified proteins in substance and energy metabolism, stress tolerance, protein degradation, and cell defense are discussed. The salt tolerance of the transgenic rapeseed was significantly improved by the introduction of the OsNAS1 gene from Brazilian upland rice of Oryza sativa (cv. IAPAR 9). Brassica napus, nicotianamine synthase (NAS), salt-stress, differential proteins Citation:Kong F, Mao S J, Du K, et al. Comparative proteomics analysis of OsNAS1 transgenic Brassica napus under salt stress.