The insectivorous sundew (Drosera rotundifolia, L.) might be a novel source of PR genes for biotechnology

The gene pool of insectivorous sundew, Drosera rotundifolia L., was studied to identify and analyse sequences encoding for pathogenesis-related (PR) proteins. The digested genomic DNA was in ¿inverted¿ Southern hybridisation probed to 19 clones for PR genes from different plant sources. From representatives of PR subgroups 1¿5, 8 and 9, genes for glucanases (PR-2), chitinases (PR-3) and thaumatin-like proteins (PR-5) were hybridising. A PCR approach using degenerated primers was chosen to isolate sequences of sundew glucanase gene. Translation of a 500 bp long putative glucanase revealed similarity to catalytic domain of other glucanase amino acid sequences. Despite the peculiarity of this sequence, it contains all conserved amino acid residues important for catalysis. The sequence obtained in this study represents one of the first sequences encoding for nuclear genes in sundews reported, and brings the first evidence for presence of glucanases in sundew. The potential use of this sequence in biotechnology is considered as well

Tentacles of in vitro-grown round-leaf sundew (Drosera rotundifolia L.) show induction of chitinase activity upon mimicking the presence of prey

Induction of plant-derived chitinases in the leaves of a carnivorous plant was demonstrated using aseptically grown round-leaf sundew (Drosera rotundifolia L.). The presence of insect prey was mimicked by placing the chemical inducers gelatine, salicylic acid and crustacean chitin on leaves. In addition, mechanical stirring of tentacles was performed. Chitinase activity was markedly increased in leaf exudates upon application of notably chitin. Application of gelatine increased the proteolytic activity of leaf exudates, indicating that the reaction of sundew leaves depends on the molecular nature of the inducer applied. In situ hybridization of sundew leaves with a Drosera chitinase probe showed chitinase gene expression in different cell types of non-treated leaves, but not in the secretory cells of the glandular heads. Upon induction, chitinase mRNA was also present in the secretory cells of the sundew leaf. The combined results indicate that chitinase is likely to be involved in the decomposition of insect prey by carnivorous plants. This adds a novel role to the already broad function of chitinases in the plant kingdom and may contribute to our understanding of the molecular mechanisms behind the ecological success of carnivorous plants in nutritionally poor environment

Expression of a cucumber class III chitinase and Nicotiana plumbaginifolia class I glucanase genes in transgenic potato plants

The genes encoding for a cucumber class III chitinase and Nicotiana plumbaginifolia class I glucanase were co-introduced into Slovak potato (Solanum tuberosum L.) breeding line 116/86 using Agrobacterium tumefaciens. For both transgenes the number of integrated copies and level of RNA expression were determined. These analyses demonstrated low variation and significant correlation in expression of the introduced transgenes. The effect of transgene expression on fungal susceptibility of transformants was evaluated in vitro. Hyphal extension assays revealed no obvious differences in the ability of extracts from transformants to inhibit growth of Rhizoctonia solani comparing to non-transformed potato

Genetic transformation of Slovak cultivar of potato (Solanum tuberosum L.): efficiency and the behavior of the transgene

Transgenic potato plants (Solanum tuberosum L.) of selected Slovak cultivars (cvs.) and one breeding line were obtained by Agrobacterium-mediated transformation. In vitro-grown plants of cvs. Albina, Eta, Malvina, Vila and line 116/86 were tested for their ability to regenerate transgenic plants. Infection of leaf explants and internodes except of those of cv. Albina resulted in the regeneration of transgenic shoots. Transformation efficiency was genotype dependent. A greater number of transformants was obtained from line 116/86 using leaf disc transformation than was obtained from the reference cultivar Desirere. The activity of GUS transgene was measured in populations of transgenic plants 116/86(GHN) and Desire¿e(GHN). The genotype had no significant influence on GUS transgene expression levels. High transgene copy number resulted in increased variation of transgene expression among plants 116/86(GHN)