ENETIC analysis implying mutable alleles of the gene V to account for flower color variegation in a Nicotiana culture has been presented by SMITH and SAND (1957). These plants also contain stable genes for flower color and have been found useful for the study of interaction between environmental factors and genetic systems of varying stability (SAND 1957; SAND, SPARROW and SMITH 1960). The goal...

A binary vector carrying two WUSCHEL-related homeobox (WOX) genes, WOX2 and WOX8, under the control of a chemical-inducible expression system, worked in transformation N. paniculata, recalcitrant species Nicotiana. The resulting transformants exhibited improved culture performance regeneration from leaf segments suspended cells. Multicellular masses generated freely cells showed specific cell d...

A powdery mildew disease was observed on leaves of Solanum gilo, S. melongena, S. tuberosum S. chacoense, Nicotiana rustica and N. tabacum in Brasília (Federal District), Brazil. Symptoms were mainly characterized by adaxial yellow areas in the leaves corresponding to white fungal colonies on the abaxial surface. Profuse sporulation was often observed. Light microscopy of the fungal colonies re...

BACKGROUND AND METHODS Polyploidy results in genetic turmoil, much of which is associated with new phenotypes that result in speciation. Five independent lines of synthetic allotetraploid N. x obtusiata (N x o) were created from crosses between the diploid N. attenuata (Na) (male) and N. obtusifolia (No) (female) and the autotetraploids of Na (NaT) and No (NoT) were synthesized. Their genetic, ...

In Nicotiana alata, self-incompatibility is controlled by a single locus, designated the S-locus, with multiple alleles. Stylar products of these alleles are ribonucleases that are secreted mainly in the transmitting tract tissues. N. tabacum plants were transformed with constructs containing the S2-cDNA and genomic S2-sequences from N. alata that were linked to the cauliflower mosaic virus 35S...

BACKGROUND AND AIMS Speciation in angiosperms can be accompanied by changes in floral colour that may influence pollinator preference and reproductive isolation. This study investigates whether changes in floral colour can accompany polyploid and homoploid hybridization, important processes in angiosperm evolution. METHODS Spectral reflectance of corolla tissue was examined for 60 Nicotiana (...

Nicotiana benthamiana often displays more intense symptoms after infection by RNA viruses than do other Nicotiana species. Here, we examined the role of RNA-dependent RNA polymerases (RdRPs) in N. benthamiana antiviral defense. cDNAs representing only two genes encoding RdRPs were identified in N. benthamiana. One RdRP was similar in sequence to SDE1/SGS2 required for maintenance of transgene s...

A new variety of Nicotiana edwardsonii, designated N. edwardsonii cv. Columbia, expresses pathogenesis-related (PR) proteins in a temporal manner 45 to 49 days postplanting and also exhibits enhanced resistance to Tobacco mosaic virus, Tobacco necrosis virus, and Tomato bushy stunt virus. In contrast, PR proteins were not expressed in the original N. edwardsonii variety at comparable ages but w...

Genomics-based breeding of economically important crops such as banana, coffee, cotton, potato, tobacco and wheat is often hampered by genome size, polyploidy and high repeat content. We adapted sequence-based whole-genome profiling (WGP™) technology to obtain insight into the polyploidy of the model plant Nicotiana tabacum (tobacco). N. tabacum is assumed to originate from a hybridization even...

Allopolyploid speciation occurs instantly when the genomes of different species combine to produce self-fertile offspring and has played a central role in the evolution of higher plants, but its consequences for adaptive responses are unknown. We compare herbivore-recognition and -resistance responses of the diploid species and putative ancestral parent Nicotiana attenuata with those of the two...