Coexistence of cytoplasmic and nuclear genes for male sterility in Petunia

Summary Cytoplasmic male sterility (cms) and nuclear male sterility (nms) in Petunia were described respectively as possible autonomous and integrated states of the same genetic element by Frankel (1971). In the present study we describe genetic analysis of the interaction between the cms, the nuclear gene for male sterility (e) and the fertility restorer allele (Rf). The main findings in this study are: (1) The nuclear sterility allele can coexist in one or two dosages with the cytoplasmic male sterility elements (ste) in somatic cells or female gametes; (2) the presence of the fertility restorer allele Rf is not required for the coexistence of ste and e and (3) Rf does not interact epistatically with e, e.g., the expression of e is independent of Rf—the genotypes (S) RfRfee and (S) Rfrfee are male sterile.Contribution from the Agricultural Research Organization. The Volcani Center, Bet Dagan, Israel. 1983 series No. 846 E     

Involvement of two differenturf-s related mitochondrial sequences in the molecular evolution of the CMS-specificS-Pcf locus in petunia

In petunia, a mitochondrial (mt) locus,S-Pcf, has been found to be strongly associated with cytoplasmic male sterility (CMS). TheS-Pcf locus consists of three open reading frames (ORF) that are co-transcribed. The first ORF,Pcf, contains parts of theatp9 andcoxII genes and an unidentified reading frame,urf-s. The second and third ORFs contain NADH dehydrogenase subunit 3 (nad3) and ribosomal protein S12 (rps12) sequences, respectively. Thenad3 andrps12 sequences included in theS-Pcf locus are identical to the corresponding sequences on the mt genome of fertile petunia. In both CMS and fertile petunia, only a single copy ofnad3 andrps12 has been detected on the physical map of the main mt genome. The origin of theurf-s sequence and the molecular events leading to the formation of the chimericS-Pcf locus are not known. This paper presents evidence indicating that two different mt sequences, related tourf-s and found in fertile petunia lines (orf-h and Rf-1), might have been involved in the molecular evolution of theS-Pcf locus. Southern analysis of mtDNA derived from both fertile and sterile petunia plants suggests that one of theseurf-s related sequences (showing 100% homology tourf-s and termedorf-h) is located on a sublimon. An additional, low-homologyurf-s related sequence (Rf-1) is shown to be located on the main mt genome 5′ to thenad3 gene. It is, thus, suggested that the sequence of events leading to the generation of theS-Pcf locus might have involved introduction of theorf-h sequence, via homologous recombination, into the main mt genome 5′ tonad3 at the region where the Rf-1 sequence is located.     

Involvement of two differenturf-s related mitochondrial sequences in the molecular evolution of the CMS-specificS-Pcf locus in petunia

In petunia, a mitochondrial (mt) locus,S-Pcf, has been found to be strongly associated with cytoplasmic male sterility (CMS). TheS-Pcf locus consists of three open reading frames (ORF) that are co-transcribed. The first ORF,Pcf, contains parts of theatp9 andcoxII genes and an unidentified reading frame,urf-s. The second and third ORFs contain NADH dehydrogenase subunit 3 (nad3) and ribosomal protein S12 (rps12) sequences, respectively. Thenad3 andrps12 sequences included in theS-Pcf locus are identical to the corresponding sequences on the mt genome of fertile petunia. In both CMS and fertile petunia, only a single copy ofnad3 andrps12 has been detected on the physical map of the main mt genome. The origin of theurf-s sequence and the molecular events leading to the formation of the chimericS-Pcf locus are not known. This paper presents evidence indicating that two different mt sequences, related tourf-s and found in fertile petunia lines (orf-h and Rf-1), might have been involved in the molecular evolution of theS-Pcf locus. Southern analysis of mtDNA derived from both fertile and sterile petunia plants suggests that one of theseurf-s related sequences (showing 100% homology tourf-s and termedorf-h) is located on a sublimon. An additional, low-homologyurf-s related sequence (Rf-1) is shown to be located on the main mt genome 5′ to thenad3 gene. It is, thus, suggested that the sequence of events leading to the generation of theS-Pcf locus might have involved introduction of theorf-h sequence, via homologous recombination, into the main mt genome 5′ tonad3 at the region where the Rf-1 sequence is located. Contribution [No. 1581-E (1995 series)] from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel 50 250     

Physical mapping of plastid DNA variation among eleven Nicotiana species

Summary Plastid DNA of seven American and four Australian species of the genus Nicotiana was examined by restriction endonuclease analysis using the enzymes Sal I, Bgl I, Pst I, Kpn I, Xho I, Pvu II and Eco RI. These endonucleases collectively distinguish more than 120 sites on N. tabacum plastid DNA. The DNAs of all ten species exhibited restriction patterns distinguishable from those of N. tabacum for at least one of the enzymes used. All distinctive sites were physically mapped taking advantage of the restriction cleavage site map available for plastid DNA from Nicotiana tabacum (Seyer et al. 1981). This map was extended for the restriction endonucleases Pst I and Kpn I. In spite of variation in detail, the overall fragment order was found to be the same for plastid DNA from the eleven Nicotiana species. Most of the DNA changes resulted from small insertions/deletions and, possibly, inversions. They are located within seven regions scattered along the plastid chromosome. The divergence pattern of the Nicotiana plastid chromosomes was strikingly similar to that found in the genus Oenothera subsection Euoenothera (Gordon et al. 1982). The possible role of replication as a factor in the evolution of divergence patterns is discussed. The restriction patterns of plastid DNA from species within a continent resembled each other with one exception in each instance. The American species N. repanda showed patterns similar to those of most Australian species, and those of the Australian species N. debneyi resembled those of most American species.Abbreviations ims isonuclear male sterile - ptDNA plastid chloroplast DNA - Rubisco ribulosebisphosphate carboxylase/oxygenase - kbp kilobase pairs - LSU large subunit of Rubisco     

Improved efficiency of plant regeneration from protoplasts of eggplant Solanum melongena L.

Eggplant (Solanum melongena L.) mesophyll protoplasts were obtained from in vitro growing plants of line 410 and cv. Classic. Relatively high (15%) plating efficiency was achieved using petri dishes with alternate quadrants containing reservoir medium (R medium + 1% activated charcoal) and culture medium. Shoot regeneration occurred within 6 weeks following initiation of protoplast culture.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan Israel, No. 1164-E, 1984 Series.     

Shoot regeneration in root cultures of Solanaceae

Root cultures from several species of the Solanaceae were initiated and subcultured on Murashige and Skoog medium without growth regulators. Direct shoot regeneration was observed in four different species. The effect of several concentrations of auxin (IAA) and cytokinins (BAP, zeatin) on the number of shoots generated by two highly responsive species (Nicotiana exigua, N. debneyi) is described.     

Phytomelatonin in the leaves and fruits of wild perennial plants

Phytomelatonin has been documented in numerous flowering plants, mostly in cultivated species consumed by humans. Although frugivorous animals feed on fruits, the phytomelatonin content of these organs has hardly ever been tested in wild plants. The aim of this study was to determine the levels of phytomelatonin in the leaves and fleshy fruits of 31 wild perennial species known to be eaten by herbivorous and frugivorous mammals and birds. Considerable levels of phytomelatonin were found in the leaves of all the tested species, and some contained melatonin in their fruits as well. The melatonin content was found to vary significantly in different life forms (trees, shrubs, and climbers), with trees possessing the highest levels. The analysis revealed a significant positive correlation between the phytomelatonin levels in the leaves and the fruits of various species. However, the concentration found in the fruits was generally lower than that found in the leaves of the same species. Despite the presence of phytomelatonin in the fleshy fruits of different families, there was no noticeable common attribute among them. Phytomelatonin was exhibited in both the seeds and the pulp, with no obvious preference for either one. Although it was determined that ingested melatonin enters the bloodstream of birds and mammals, its specific role is still not certain. The potential impact of edible phytomelatonin on the circadian rhythm of herbivores and frugivores is discussed on the basis of these findings.     

Body Mass Index,Muscle Strength and Physical Performance in Older Adults from Eight Cohort Studies: The HALCyon Programme

Objective

To investigate the associations of body mass index (BMI) and grip strength with objective measures of physical performance (chair rise time, walking speed and balance) including an assessment of sex differences and non-linearity.

Methods

Cross-sectional data from eight UK cohort studies (total N = 16 444) participating in the Healthy Ageing across the Life Course (HALCyon) research programme, ranging in age from 50 to 90+ years at the time of physical capability assessment, were used. Regression models were fitted within each study and meta-analysis methods used to pool regression coefficients across studies and to assess the extent of heterogeneity between studies.

Results

Higher BMI was associated with poorer performance on chair rise (N = 10 773), walking speed (N = 9 761) and standing balance (N = 13 921) tests. Higher BMI was associated with stronger grip strength in men only. Stronger grip strength was associated with better performance on all tests with a tendency for the associations to be stronger in women than men; for example, walking speed was higher by 0.43 cm/s (0.14, 0.71) more per kg in women than men. Both BMI and grip strength remained independently related with performance after mutual adjustment, but there was no evidence of effect modification. Both BMI and grip strength exhibited non-linear relations with performance; those in the lowest fifth of grip strength and highest fifth of BMI having particularly poor performance. Findings were similar when waist circumference was examined in place of BMI.

Conclusion

Older men and women with weak muscle strength and high BMI have considerably poorer performance than others and associations were observed even in the youngest cohort (age 53). Although causality cannot be inferred from observational cross-sectional studies, our findings suggest the likely benefit of early assessment and interventions to reduce fat mass and improve muscle strength in the prevention of future functional limitations.