Comparative Transcriptomic Profiling of a Salt-Tolerant Wild Tomato Species and a Salt-Sensitive Tomato Cultivar

Wild halophytic tomato has long been considered as an ideal gene donor for improving salt tolerance in tomato cultivars. Extensive research has been focused on physiological and quantitative trait locus (QTL) characterization of wild tomato species in comparison with cultivated tomato. However, the global gene expression modification of wild tomato in response to salt stress is not well known. A wild tomato genotype, Solanum pimpinellifolium ‘PI365967’ is significantly more salt tolerant than the cultivar, Solanum lycopersicum ‘Moneymaker’, as evidenced by its higher survival rate and lower growth inhibition at the vegetative stage. The Affymetrix Tomato Genome Array containing 9,200 probe sets was used to compare the transcriptome of PI365967 and Moneymaker. After treatment with 200 mM NaCl for 5 h, PI365967 showed relatively fewer responsive genes compared with Moneymaker. The salt overly sensitive (SOS) pathway was found to be more active in PI365967 than in Moneymaker, coinciding with relatively less accumulation of Na+ in shoots of PI365967. A gene encoding salicylic acid-binding protein 2 (SABP2) was induced by salinity only in PI365967, suggesting a possible role for salicylic acid signaling in the salt response of PI365967. The fact that two genes encoding lactoylglutathione lyase were salt inducible only in PI365967, together with much higher basal expression of several glutathione S-transferase genes, suggested a more effective detoxification system in PI365967. The specific down-regulation in PI365967 of a putative high-affinity nitrate transporter, known as a repressor of lateral root initiation, may explain the better root growth of this genotype during salt stress.[1]


Antihypertensive Effect of a γ-Aminobutyric Acid Rich Tomato Cultivar ‘DG03-9’ in Spontaneously Hypertensive Rats

This study aimed to investigate the effects of a γ-aminobutyric acid (GABA) rich tomato (Solanum lycopersicum L.) cultivar ‘DG03-9’ in comparison with ‘Momotaro’, a commonly consumed tomato cultivar in Japan, on systolic blood pressure (SBP) in spontaneously hypertensive rats (SHR). In a single administration study, treatment with the GABA-rich cultivar elicited a significant decrease in SBP compared to the control group. In a chronic administration study, SHR were fed diets containing one of the tomato cultivars for 4 weeks. Both cultivars significantly reduced the increase in SBP compared to the control. The antihypertensive effect of the GABA-rich cultivar was higher than that of the commonly consumed cultivar in both the single- and chronic-administration studies. Treatment with a comparable amount of GABA elicited a similar response to treatment with the GABA-rich cultivar. These results suggest that the GABA-rich cultivar ‘DG03-9’ is a potent antihypertensive food and may be useful for treating hypertension effectively.[2]


Cultivar, Maturity, and Heat Treatment on Lycopene Content in Tomatoes

Using high performance liquid chromatography, tomato cultivars which contain the Crimson gene (og) were usually found to have higher lycopene content (5086 to 5786 μg/100 g fresh weight) than those cultivars lacking the gene (2622 to 4318 μg/100 g fresh weight). A comparison of the color readings taken from tomatoes at the equatorial region with those of the homogenate prepared from the same region showed that the hue of tomato homogenate was a better indicator of lycopene content than tomato surface hue. The tomatoes’ lycopene content was not affected by ethylene treatment or cooking for 4, 8, and 16 min at 100 °C. [3]


The Effects of Trellising Methods on Determinate Tomato Varieties’ Yield in Zimbabwe

Aims: To determine the effect of trellising methods of determinate tomato varieties on fruit diameter, number of fruits per plant, marketable and total yields.

Study Design: A 3 x 4 factorial experiment in Randomized Complete Block Design with 3 replications was used

Place and Duration of Study: Mutoko district in Zimbabwe between May and October 2013

Methodology: Two factors were studied the trellising method (including staking and weave, single pole staking, caging and the ground culture as control) and the tomato varieties (Roma, Floridade and Rio Grande). The factors were studied concerning their effect on yield amount.

Results: Significant difference was found (P≤0.05) due to the trellising method, whereas the caging caused the highest results (number of fruits per plant, marketable and total yield amount). Additionally, species variability plays important role in determination of yield quality as found for Roma one as compare to the other ones Not only the trellising method alone is affecting the yield, but the suitability of the species to the trellising method, and the one which has the highest results was Roma when compared to Floridade and Rio Grande.

Conclusion: The caging method resulted in an increase in yield. Despite any trellising method used, trailing increases the amount of marketable tomatoes. These results, however, need further studies to validate reliability.[4]


Storability of Sliced Dehydrated Tomato

Three different varieties of tomatoes, Alawusa (TX1), a local variety with four lobes (TX2) and another local variety with two lobes (TX3) were sliced and dried in an oven at 55ºC for a period of four hours. The dried samples were packaged in polythene bags labeled TX1, TX2 and TX3. Proximate composition, titratable acidity and pH were monitored initially and fortnightly. The results revealed that there were no significant differences among treatments (P = 0.05) in all the parameters determined during the course of storage. The following ranges were observed among treatments in the proximate composition within the storage period: crude protein, 9.65- 16.85%; crude fiber, 14.43- 19.63%; ether extract, 0.11-3.33%; ash, 7.45-10.47% and nitrogen free extract (NFE), 58.58-65.23. Protein values were found to be decreasing during the course of storage in all treatments, whereas no definite trends were observed for pH and titratable acidity.[5]

Reference

[1] Sun, W., Xu, X., Zhu, H., Liu, A., Liu, L., Li, J. and Hua, X., 2010. Comparative transcriptomic profiling of a salt-tolerant wild tomato species and a salt-sensitive tomato cultivar. Plant and Cell Physiology, 51(6), pp.997-1006.

[2] Yoshimura, M., Toyoshi, T., Sano, A., Izumi, T., Fujii, T., Konishi, C., Inai, S., Matsukura, C., Fukuda, N., Ezura, H. and Obata, A., 2010. Antihypertensive effect of a γ-aminobutyric acid rich tomato cultivar ‘DG03-9’in spontaneously hypertensive rats. Journal of Agricultural and Food Chemistry, 58(1), pp.615-619.

[3] Thompson, K.A., Marshall, M.R., Sims, C.A., Wei, C.I., Sargent, S.A. and Scott, J.W., 2000. Cultivar, maturity, and heat treatment on lycopene content in tomatoes. Journal of Food Science, 65(5), pp.791-795.

[4] Misheck, C., Simbarashe, M., Munyaradzi, G. and Ngonidzashe, K.N., 2014. The Effects of Trellising Methods on Determinate Tomato Varieties’ Yield in Zimbabwe. International Journal of Plant & Soil Science, pp.411-416.

[5] Zaka, K.O., Arowora, K.A., Fasoyiro, S.B., Ilesanmi, F.F., Ajani, A.O., Awoite, T.M., Ikotun, I.O. and Ogundare-Akanmu, O.A., 2015. Storability of Sliced Dehydrated Tomato. Journal of Experimental Agriculture International, pp.178-181.