QTL analysis of seed germination traits in tobacco (Nicotiana tabacum L.).

Genetic mapping of seed germination traits has been performed with many plant species. In tobacco, however, investigations are rare. In the present study, a bi-parental mapping population consisting of 118 doubled haploid lines and derived from a cross between 'Beinhart-1000' and 'Hicks' was investigated. Four germination-related traits, total germination (TG), normal germination (NG), time to reach 50% of total germination (T50), and the area under the curve after 200 h of germination (AUC) were considered by examining seeds either untreated or after a moderate controlled deterioration (CD). Quantitative trait loci were found for all traits distributed on 11 out of the 24 linkage groups. It was demonstrated that, as in many other species, germination-related traits are very complex and under polygenic control.

Resistance vs. tolerance to Potato virus Y in tobacco-comparing effectiveness using virus isolates from Central Europe.

Growing resistant cultivars is the best method of protecting the crops against Potato virus Y (PVY). There are a few sources of PVY resistance/tolerance in tobacco acquired through mass selection, X-ray induced mutagenesis and introgressions from wild Nicotiana species. Here, we compare major sources of PVY resistance/tolerance in inoculation tests using ten PVY isolates collected in Central Europe (Poland and Germany) and differing with their virulence. The diversity of collected isolates was confirmed by DAS-ELISA tests and two PCR assays targeting the most common recombination sites in the PVY genome. We used these isolates in inoculation tests on five resistant cultivars 'V.SCR', 'PBD6', 'TN86', 'VAM', 'Wislica', a tolerant breeding line 'BPA' and four susceptible cultivars 'BP-210', 'K326', 'NC95', 'Samsun H'. None of the tested cultivars/breeding lines showed universal resistance against all ten isolates. However, 'VAM' and 'Wislica' appeared to be the most effective sources, as they showed no symptoms and gave negative DAS-ELISA tests for four out of ten tested PVY isolates. In contrast, tolerance of the breeding line 'BPA' was effective against all tested isolates, because inoculation did not lead to development of full disease symptoms in that breeding line.

Inheritance and effectiveness of two transgenes determining PVY resistance in progeny from crossing independently transformed tobacco lines.

Genetic transformation of plants allows us to obtain improved genotypes enriched with the desired traits. However, if transgenic lines were to be used in breeding programs the stability of inserted transgenes is essential. In the present study, we followed the inheritance of transgenes in hybrids originated from crossing two transgenic tobacco lines resistant to Potato virus Y (PVY): MN 944 LMV with the transgene containing Lettuce mosaic virus coat protein gene (LMV CP) and AC Gayed ROKY2 with PVY replicase gene (ROKY2). Progeny populations generated by successive self-pollination were analyzed with respect to the transgene segregation ratio and resistance to Potato virus Y in tests carried out under greenhouse conditions. The presence of the virus in inoculated plants was detected by DAS-ELISA method. The results demonstrated the Mendelian fashion of inheritance of transgenes which were segregated independently and stably. As a result, we obtained T4 generation of hybrid with both transgenes stacked and which was highly resistant to PVY.

Chemical Polymorphism of Origanum compactum Grown in All Natural Habitats in Morocco.

Origanum compactum L. (Lamiaceae) is one of the most important medicinal species in term of ethnobotany in Morocco. It is considered as a very threatened species as it is heavily exploited. Its domestication remains the most efficient way to safeguard it for future generations. For this purpose, wide evaluation of the existing variability in all over the Moroccan territory is required. The essential oils of 527 individual plants belonging to 88 populations collected from the whole distribution area of the species in Morocco were analyzed by GC/MS. The dominant constituents were carvacrol (0 - 96.3%), thymol (0 - 80.7%), p-cymene (0.2 - 58.6%), γ-terpinene (0 - 35.2%), carvacryl methyl ether (0 - 36.2%), and α-terpineol (0 - 25.8%). While in the Middle Atlas region and the Central Morocco mainly carvacrol type samples were found, much higher chemotypic diversity was encountered within samples from the north part of Morocco (occidental and central Rif regions). The high chemical polymorphism of plants offers a wide range for selection of valuable chemotypes, as a part of breeding and domestication programs of this threatened species.

The inheritance of wheat grain longevity: a comparison between induced and natural ageing.

Seed longevity is an important trait for both ex situ genebanks and the seed industry. It is partially determined by genetic factors, but is also dependent on the environmental conditions experienced by the mother plant during seed maturation, as well as those imposed during the post-harvest and storage periods. For practical reasons, the variation in longevity has repeatedly been analysed by treating fresh seed to various induced ageing protocols, but the extent to which these procedures mimic the natural ageing process remains debatable. Here, a comparison was attempted between the wheat genomic regions identified by biparental mapping as harbouring determinants of viability loss identified in grain which had been either aged artificially or had been stored long term. Only one locus proved to be shared, but even here, the parental origin of the positive allele differed. Correlation analysis revealed no relationship between various induced ageing treatments and long-term storage.

Determination of polyphenols in Mentha longifolia and M. piperita field-grown and in vitro plant samples using UPLC-TQ-MS.

Nine polyphenols in the aerial parts of Mentha longifolia have been separated by chromatographic techniques. Their structures have been confirmed by HPLC/electrospray ionization-MS/MS. The compounds identified included rosmarinic acid, salvianolic acid L, dedihydro-salvianolic acid, luteolin-glucuronide, luteolin-diglucuronide, luteolin-glucopyranosyl-rhamnopyranoside, and eriodictyol-glucopyranosyl-rhamnopyranoside. The extracts of M. longifolia and M. piperita field plants, in vitro plants, callus tissues, and cell suspension cultures were profiled, and their polyphenol composition was compared in different tissues and quantified using ultra-performance column liquid chromatography (UPLC)/triple-quadrupole-MS in the selected-ion recording detection mode. Determination of desired compounds was based on calibration curves obtained for standards, which were previously isolated from M. longifolia aerial parts. The UPLC profiles revealed considerable differences in the synthesis of secondary metabolites among samples coming from field plants, in vitro plants, callus tissues, and cell suspension cultures. Plant tissues coming from field cultivation (for both M. piperita and M. longifolia) contained several phenolic compounds (flavonoids and phenolic acids), whereas plants from in vitro conditions, callus tissues, and suspension cultures contained only a few of them. Rosmarinic acid dominated in all of these samples. These results show that under in vitro conditions, the metabolism of phenolics undergoes a fundamental change.