A Somaclonal Variant of Rose-Scented Geranium (Pelargonium spp.) with Moderately High Content of Isomenthone in its Essential Oil

Rose-scented geranium ( Pelargonium spp.), which is highly valued for its essential oil, is exclusively propagated vegetatively. Hence no genetic improvement work is possible through conventional breeding. Somaclonal variation was generated with and without in vitro mutagenesis using N-nitroso- N-methyl urea (NMU) in an Indian cultivar ‘Bourbon’, and a clone ‘Narmada’. A somaclonal variant (N75) with a moderately high content of isomenthone in its essential oil was isolated from somaclones generated after treatment of internodal explants of clone, ‘Narmada’ with 0.25 mM NMU for 1 h. The contents of isomenthone in its essential oil were 26% and 35%, respectively, in SC2/VM2 and SC3/VM3 generations (second and third vegetative generations, respectively, after in vitro mutagen treatment) as compared with 0.7% and 0.3%, respectively, in the parental clone, ‘Narmada’. The contents of alcohols and their esters (linalool, citronellol, geraniol, citronellyl formate and geranyl formate) in the essential oil of N75 in SC2/VM2 and SC3/VM3 generations were 49% and 35%, respectively, as compared with 69% and 63%, respectively, in the parental clone, ‘Narmada’. This is the first report on a chemovariant of rose-scented geranium with a moderately high content of isomenthone. All earlier reported isomenthone-rich variants of rose-scented geranium had quite high contents of isomenthone (64-71%) in their essential oils. The probable modes of origin of this somaclonal variant, its parental clone ‘Narmada’ (with very low content of isomenthone) and four earlier reported isomenthone-rich variants of Indian cultivars of geranium are discussed.

Molecular profiling of Vitis vinifera Chardonnay obtained by somatic embryogenesis

<p style="text-align: justify;">With the help of microsatellite profiling, we showed that <em>Vitis vinifera</em> Chardonnay clone 96 is a periclinal chimera plant which is composed at least of two distinct cell layers. Performing somatic embryogenesis allowed us to separate the two cell layers and to regenerate L1 plants. These regenerated L1 plants did not show phenotypic differences to the parental clone when grown in greenhouse conditions, suggesting therefore that the phenotype of Chardonnay 96 did not result of an interaction between the two distinct cell layers L1 and L2.</p>

Resistance Response of the Ma genes from `Myrobalan' Plum to Meloidogyne hapla and M. mayaguensis

In `Myrobalan' plum (Prunus cerasifera Ehr.), Ma1 and Ma2 are single major dominant genes that control the resistance to the predominant root-knot nematode (RKN) species Meloidogyne arenaria (Neal) Chitwood, M. incognita (Kofoid & White) Chitwood, and M. javanica (Treub). These genes were evaluated for activity to the northern RKN M. hapla Chitwood and the tropical RKN M. mayaguensis Rammah & Hirschmann, neither of which is controlled by the Mi gene from tomato. This study was conducted under greenhouse conditions using a resistance screening based on high and durable inoculum pressure by the nematodes. Tests were conducted simultaneously for: M. arenaria (as a reference for the Ma genes); M. hapla and M. mayaguensis from crosses segregating for either Ma2 alone or Ma2 and Ma1 and involving the resistant parental clones P.2175 (heterozygous for Ma1) and P.1079 (homozygous for Ma2); and the host parental clone P.2646 (recessive for both Ma genes). Each parental clone and each individual of the segregating progenies reacted in a similar way to M. arenaria and M. mayaguensis, indicating that the Ma genes also control resistance to M. mayaguensis. By contrast, all parental clones and progenies were completely resistant to M. hapla, and, despite high inoculum pressure, no effect of the Ma genes on this species could be established.

Recloning of SV40 early gene transfected human endothelial cells repeatedly recovers subpopulations with low passage characteristics and morphologies

Cultured human umbilical vein endothelial cells (HUVECs) are a valuable model for investigation of endothelial functions, but they enter senescence at low passage. Transfection of early passage HUVECs with the early genes of SV40 greatly extends the replicative potential of these cells, but eventually results in marked changes in growth, morphology, and biochemistry. Here we report a modified approach that appears to have overcome the problem of late passage decline after transfection. Plasmid pX-8 containing the SV40 early genes was transfected into passage four HUVECs. At passage five, these transfectants were cloned by limiting dilution and selected on the basis of both morphological and biochemical resemblance to their untransfected counterparts. Two clones that expressed factor VIII and in which the basal and the tumor necrosis factor-α inducible levels of interleukin 6 and endothelial adhesion molecules were normal were chosen. Vimentin and fibronectin distribution in these clones resembled untransfected cells. At passage 25, growth pattern changes were becoming evident, but recloning these late passage clones recovered numerous subclones of normal, cobblestone appearance. Two of these were further characterized and found to resemble their original parental clone by all of the biochemical criteria listed above. These subclones appeared to transform more rapidly than the parental clone, but repeated subcloning again rescued clones with normal morphologies and normal biochemical characteristics. We conclude that periodic recloning may indefinitely perpetuate lines that are useful equivalents of their original counterparts.Key words: SV40, endothelial, immortalized, adhesion molecules.