Abstract
The abstract for the paper, “Effect of the Fruit-ripening Mutant Genes rin and nor on the Flavor of Tomato Fruit” by E. Kopeliovitch, Y. Mizrahi, H. D. Rabinowitch, and N. Kedar [J. Amer. Soc. Hort. Sci. 107(3):361–364. 1982.], contains several errors. The correct version of the abstract is as follows: Organoleptic tests of the nonripening tomato mutants rin and nor and their F1 hybrids with the normal-fruit-bearing cultivar ‘Rutgers’ indicated that fruits of the rin heterozygous plants (rin/+) were slightly inferior and that those of heterozygote nor (nor/+) were distinctly inferior in flavor to fruits of the normal genotype (+/+), all sampled 3–5 days after ethylene and CO2 evolution rates attained maximum levels. The flavor of fruits of the double heterozygotes rin/+, nor/+ was poorer than either of the 2 single-gene heterozygotes, while fruits of both homozygous plants, nor/nor and rin/rin, were unpalatable. Analyses of pH, titratable acidity, total soluble solids, and reducing sugars did not indicate that any of these parameters are responsible for the inferior flavor of the genotypes containing the nonripening genes. Comparisons of reciprocal crosses provided no evidence of cytoplasmic inheritance of fruit flavor.
Abstract
Organoleptic tests of the non-ripening tomato mutants rin and nor and their F1 hybrids with the normal-fruit-bearing cultivar ‘Rutgers’ indicated that fruits of the rin heterozygous plants (rin/+) were slightly inferior and that those of inferior in flavor to fruits of the normal genotype (+/+), all sampled 3–5 days after ethylene and CO2 evolution rates attained maximum levels. The flavor of fruits of the double heterozygote nor heterozygotes (nor/+) were distinctly rin/+, nor/+ was poorer than either of the 2 single-gene heterozygotes, while fruits of both homozygous plants, nor/nor and rin/rin, were unpalatable. Analyses of pH, titratable acidity, total soluble solids, and reducing sugars did not indicate that any of these parameters is responsible for the inferior flavor of the genotypes containing the non-ripening genes. Comparisons of reciprocal crosses provided no evidence of cytoplasmic inheritance of fruit flavor.
Abstract
Low levels of abscisic acid (ABA) were found at 10 days after anthesis in fruits of a normal cultivar (‘Rutgers’) and of the abnormal ripening mutants (Nr, rin and nor) of tomato (Lycopersicon esculentum Mill). Thereafter the levels increased to peak values which preceded or coincided with coloring in all strains. Peak levels of ABA coincided with the completion of growth in ‘Rutgers’ and rin but followed completion of growth in Nr and nor. Phaseic acid (PA) and gibberellin (GA) activity were highest in all strains about 10 days after anthesis. Subsequently the levels decreased then rose to a second peak except for PA in rin which remained at a relatively high level from 20 days until completion of growth. The second peak in PA in Rutgers, Nr and nor coincided approximately with peak levels of ABA, the second peak in gibberellin activity preceded the peak of ABA in Rutgers, Nr and rin but coincided with it in nor. The results showed that the patterns in the levels of ABA, PA and gibberellin from about 14 days after anthesis are related to ripening or senescence in the four strains and not to growth.
by LeHB-1 silencing. Transcriptional profiling studies indicate that amounts of TFs show expression alterations during fruit development and ripening consistent with functions ( Arhondakis et al., 2016 ). Mutations of TF genes, including LeMADS-RIN
Sinaloa tomato growers continuously evaluate new varieties, looking for better quality and long shelf life. Mutant fruit with the genes rin and nor offers both possibilities when crossed with normal fruit. Our study presents results of 16 tomato hybrid lines harvested from the field at the “turning” stage and stored under simulated marketing conditions (20°C and 80% RH). Twelve experimental hybrids were from the rin type, one from the nor type, two commercial hybrids were normal, and one commercial line from the rin type. Sampling was done every 2 days up to 16 days. Evaluations done included physical, chemical, and physiological determinations. Line S69 (nor type) had higher firmness compared to the others, while normal lines (S121 and S123) were the softest. S69 was the only hybrid that did not completed a red external color development. Experimental lines of the rin type presented acceptable development of red color, however, only normal lines (S121 and S123) reached the characteristic red color of tomato. Lines of the rin type (S172 and S200) lost more weight during marketing than normal ones. Pulp pH was higher on the experimental rin lines than on the commercial ones (BR84, S121 and S123). Not difference on the sugar: acid ratio among the lines was found. Only normal lines showed a climateric CO2 and C2H4 peak.
Recent advances in molecular genetics and genomics technologies have had a significant impact on tomato research over the last decade and are likely to have considerable influence on the nature and outcome of research activities related to tomato in the future. Specific applications of genomics technologies in our laboratory include positional cloning of genes associated with fruit ripening and quality (rin and nor), localization of ripening-related genes on the molecular-marker map to assist candidate gene discovery related to fruit ripening and quality, and characterization of mutants influencing fruit quality and nutritional value with the goal of identifying candidate genes for said mutants and alternative molecular tools for modification of fruit quality and nutrition. Isolation of the rin and nor genes has been verified via complementation of corresponding mutant tomato plants via insertion of the appropriate CaMV35s-driven wild-type sense cDNA. Both the rin and nor genes have sequence characteristics suggestive of transcription factors. Preliminary evidence suggests the role of similar genes in the ripening of additional climacteric and non-climacteric fruit species. Additional efforts in the laboratory include molecular analyses of light signal transduction as related to 1) regulation of carotenoid and flavonoid accumulation, and 2) potential manipulation of corresponding pathways for modification of fruit quality and nutrient value.
Ripening mutant gene rin (ripening inhibitor) in tomato inhibits, or greatly slows down, a wide range of processes related to ripening of the fruit, leading to a markedly extended shelf life. Although the use of films or coatings has been shown to retard ripening, the natural film that covers the fruit and delimits interchange with the environment, the cuticle, has not been well-characterized and related to ripening. The objective of this work was to characterize cuticle changes and establish their relationship with respiratory behavior. Turning tomato fruits with the gene rin, selection S-164 and normal tomato fruits were stored under marketing conditions (20C; 65% to 70% RH) to determine cuticular and physiological changes. Parameters evaluated were: cuticular weight changes (CW), permeability, soluble cuticular lipids (SCL), and epicuticular waxes (EW). In addition CO2 production was monitored every other day. Normal fruit increased in CW from 1.17 to 1.30 mg·/cm–2 and its EW from 11.49 to 24.49 μg·cm–2. On the other hand, rin tomatoes declined in CW and EW during storage. Both kind of fruits decreased their SCL content. Normal tomatoes exhibited the characteristic climacteric peak and showed an increase of cuticle permeability, while in rin tomatoes, these changes were not expressed.
.sp. lycopersici (Sacc.) Snyd. Hans.] (races 1, 2), and Tomato spotted wilt virus (TSWV). It combines the rin and crimson genes, which improve the shelf life and lycopene content of the tomato fruit, respectively. Origin ‘Mountain Lion’, the F 1 hybrid of
combination of the Ph-2 and Ph-3 genes ( Gardner and Panthee, 2010a ). NC 2 Grape is an indeterminate, compact growth habit (brachytic, br gene) grape tomato line, which has a high sugar level and carries the ripening inhibitor ( rin ) gene ( Gardner and
-6 ( Fig. 2 ). NC 2 Grape has the ripening inhibitor gene ( rin ) derived from the large fruited rin line 9565(x)-3. Description ‘Santa’ is a popular grape hybrid tomato and is used as a standard control in variety trials. All three grape tomato lines