Cucumber (Cucumis sativus L.), a widely cultivated crop, has originated from Eastern Himalayas and secondary domestication regions includes highly divergent climate conditions e.g. temperate and subtropical. We wanted to uncover adaptive genome differences between the cucumber cultivars and what sort of evolutionary molecular mechanisms regulate genetic adaptation of plants to different ecosystems and organism biodiversity. Here we present the draft genome sequence of the Cucumis sativus genome of the North-European Borszczagowski cultivar (line B10) and comparative genomics studies with the known genomes of: C. sativus (Chinese cultivar – Chinese Long (line 9930)), Arabidopsis thaliana, Populus trichocarpa and Oryza sativa. Cucumber genomes show extensive chromosomal rearrangements, distinct differences in quantity of the particular genes (e.g. involved in photosynthesis, respiration, sugar metabolism, chlorophyll degradation, regulation of gene expression, photooxidative stress tolerance, higher non-optimal temperatures tolerance and ammonium ion assimilation) as well as in distributions of abscisic acid-, dehydration- and ethylene-responsive cis-regulatory elements (CREs) in promoters of orthologous group of genes, which lead to the specific adaptation features. Abscisic acid treatment of non-acclimated Arabidopsis and C. sativus seedlings induced moderate freezing tolerance in Arabidopsis but not in C. sativus. This experiment together with analysis of abscisic acid-specific CRE distributions give a clue why C. sativus is much more susceptible to moderate freezing stresses than A. thaliana. Comparative analysis of all the five genomes showed that, each species and/or cultivars has a specific profile of CRE content in promoters of orthologous genes. Our results constitute the substantial and original resource for the basic and applied research on environmental adaptations of plants, which could facilitate creation of new crops with improved growth and yield in divergent conditions.

The investigations performed over recent few years have proved the existence of caspase-like proteases in plants. Three groups of caspase-like proteases: metacaspases, legumain family proteases (VPEs) and saspases have been identified and characterized in plants so far. A considerable amount of evidence supports the role of these enzymes in programmed cell death (PCD) occurring during plant development, their organ senescence as well as hypersensitive response (HR) after pathogen attack. Current knowledge of these enzyme molecular and biochemical structures is summarized in the paper. The homology of caspase-like proteases to animal caspases has been also indicated. Some future perspectives of research concerning the signal pathway during PCD, the regulation of activity and mode of action of these proteases are presented in the article.

Cloning using bacterial artificial chromosomes (BACs) can yield high quality genomic libraries, which are used for the physical mapping, identification and isolation of genes, and for gene sequencing. A BAC genomic library was constructed from high molecular weight DNA (HMW DNA) obtained from nuclei of the cucumber (Cucumis sativus L. cv. Borszczagowski; B10 line). The DNA was digested with the HindIII restriction enzyme and ligated into the pCC1BAC vector. The library consists of 34,560 BAC clones with an average insert size of 135 kb, and 12.7x genome coverage. Screening the library for chloroplast and mitochondrial DNA content indicated an exceptionally low 0.26% contamination with chloroplast DNA and 0.3% with mitochondrial DNA.

Analyzing of sequences similarities is the first and most important method used to find out the function of unknown nucleotides. Searching of homologs should be done carefully not to loose any important ones. Having thousands of results from various long-read sequencing projects (ie. differentially expressed tags, genomic polymorphons or BAC ends), the by-hand ability to retrieve interesting (to our goal) similarities in hundreds of Blast results decreases rapidly. Decreasing the number of retrieved sequences by giving more stringency in e-value threshold or displaying less results could lead to false deductions. Functional genomics, proteomics and metabolomics could give us answers to the role of nucleotide sequences. It makes the need to annotate as much of the homologies as we can, to proper molecular function, biological process and cellular component (as its proposed by widely accepted Gene Ontology Consortium annotations or MapMan mappings by Max-Planc-Institute).To facilitate fast retrieval of interesting Blast homologies and making right deductions about the biological role of sequences, in big sequencing projects, the new Perl script BRAGOMAP was written. The program make use of some of BioPerl modules as well as the power of regex text-mining in the Perl itself.The script gives us the possibility to find interesting sequence similarities by using keywords and giving points for each one found. It collects all important information from the GenBank data and puts it in different columns of tab-delimited file for further use. If we were interested (for example) in flower differentiation genes we could use the keywords (flower, ovule, anther, etc.) and/or filter all the homologies isolated from flower tissues in a special development stage. We can also filter results by choosing similarities to interesting genes or protein products. This script retrieve also all standard information from the Blast and GenBank files as Description, ACC no., E-value, Similarity positions, Query Length, Percent of Similarity etc. Automatic GO and MapMan annotations are done by looking for genes, protein products and /or DB references in the proper mappings files. Here we present the usefulness of the script in analyzing sequence similarities and annotations mapping of 3855 BAC ends obtained from the HindIII BAC genomic library of cucumber (Cucumis sativus L., line B10).