New report of Phoma glomerata on Coriandrum sativum L.

In 2011, coriander plants (Coriandrum sativum L.), showing symptoms of greyish to hell brown lesions with dark brown border between discoloured and asymptomatic tissues, were observed in Bulgaria. Pycnidia with small unicellular conidia appeared in the pale centre of the lesions. In this work, the identification of the causal agent of this disease was made applying Koch's postulates. Moreover, for a rapid and unambiguous identification of the fungal species, the internal transcribed spacers and the 5.8 rDNA gene (ITS1-5.8-ITS2) were amplified by PCR from DNA extracted from the isolated colonies. The amplicon was sequenced and analyzed using BLASTn, and showed a homology of 100% with a corresponding sequence of Phoma glomerata (accession number DQ093699). The fungus isolated, after the morphological and molecular characterization, was ascribed to the species Phoma glomerata (Corda) Wollenweber and Hochapfel. This is the first report of P. glomerata as agent of stem rot of coriander in Bulgaria and elsewhere.

Improved phytoaccumulation of cadmium by genetically modified tobacco plants (Nicotiana tabacum L.). Physiological and biochemical response of the transformants to cadmium toxicity.

The response of tobacco plants (Nicotiana tabacum L.)--non-transformed and transformed with a metallothionein gene MThis from Silene vulgaris L.--to increase cadmium supply in the nutrient solution was compared. The transgenic plants accumulated significantly more Cd both in the roots and the leaves. Visual toxicity symptoms and disturbance in water balance were correlated with Cd tissue content. Treatment with 300 microM CdCl(2) resulted in inhibition of photosynthesis and mobilization of the ascorbate-glutathione cycle. Treatment with 500 microM CdCl(2) led to irreversible damage of photosynthesis and oxidative stress. An appearance of a new peroxidase isoform and changes in the leaf polypeptide pattern were observed at the highest Cd concentration. The level of non-protein thiols gradually increased following the Cd treatment both in transgenic and non-transformed plants.