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.

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Shoot proliferation is a very important micropropagation phase, decisive for economic efficiency of this method for a given taxon. To obtain a high multiplication ratio and a good quality of microshoots a detailed propagation protocol must be developed for particular species or even cultivars. Rhododendron ‘Kazimierz Odnowiciel’ is a relatively new cultivar distinguished by large, beautiful flowers and high frost resistance so there is a need to develop an efficient method of its propagation to satisfy a growing demand for this plant. The aim of the experiment was to evaluate effects of cytokinins: meta-Topolin (mT), zeatin (ZEA), 6-benzyladenine (BA), thidiazuron (TDZ), 2-isopentenyladenine (2iP), or the combination of 2iP+ZEA on proliferation of shoots in R. ‘Kazimierz Odnowiciel’ cultured on Anderson’s medium (AN). Biochemical changes in plant material affected by cytokinins during this phase of micropropagation were determined and occurrence of genetical changes was followed using ISSR markers. TDZ, ZEA or the combination of ZEA+2iP resulted in 100% explant regeneration. On the medium with TDZ or ZEA over two new shoots per explant were produced but the highest proliferation was attained on the medium containing ZEA+2iP – over three shoots per explant. Microshoots developed in this treatment had also the highest contents of chlorophyll, carotenoids and soluble sugars as well as the highest catalase activity. Microshoots formed on the medium with zeatin showed the lowest polymorphism (below 4%) relative to a stock plant.

In situ detection techniques allow specific nucleic acid sequences to be exposed in morphologically preserved tissue sections. In combination with immunocytochemistry, in situ detection can relate microscopic topological information to gene activity at the transcript or protein levels in specific tissues. The advantage of in situ methods over the conventional techniques (e.g., Northern blot, reverse transcription polymerase chain reaction [RT-PCR], or real-time PCR) is that they allow the investigation of the putative spatial distribution of nucleic acid products activity in a heterogeneous cell population. In this chapter, we describe a protocol for in situ RT-PCR detection of specific messenger RNA in cucumber (Cucumis sativus), although this protocol can be used for any plant species, floral buds, and somatic embryo tissue sections on glass microscope slides. A successful in situ RT-PCR procedure requires the optimization of many conditions related to the tissue types used, for example, a cell's age, size, and composition, which may influence the detection of RT-PCR products, as well as specific transcript availability. Moreover, parameters, such as the fixation time, thermal cycling set-up, and the time of detection of RT-PCR products, also should be optimized. The importance of the other factors also is estimated in the protocol. In addition several types of controls that are necessary for a trustworthy in situ RT-PCR method are being discussed.

Thaumatin II is an extremely sweet-tasting protein produced by fruits of the West African shrub Thaumatococcus daniellii Benth, so it can be used in biotechnology to improve the tastes of various plant products. This study is concerned with the spatial and temporal aspects of expression of the 35S-pre-prothaumatin II chimeric gene in flower buds and fruits of transgenic cucumber (Cucumis sativus L.) line 225. The activity of the 35S promoter in organs of line 225 was compared with its activity in 2 other transgenic lines. The accumulation of recombinant thaumatin varied spatially in flower bud tissues of transgenic lines. We found that these differences in the spatial accumulation of transgenic protein concerned the ovary of female buds and the perianth of male buds. In contrast to flower parts, recombinant thaumatin was found in nearly all parts of the young fruit from the transgenic plants. The pre-prothaumatin II gene expression was detected at a very early developmental stage in male buds, and its pattern was rather conserved as the buds aged. The expression of the transgene was also detected in vascular tissues of examined organs but was undetectable in pollen grains, in agreement with the generally held view that the CaMV 35S promoter is virtually silent in pollen. Immunocytochemical analyses of sections of control organs revealed endogenous homolog(s) of thaumatin when using polyclonal antisera, but not when using monoclonal antibodies for recombinant thaumatin detection in transgenic cucumber.