Maturity-Adjusted Resistance of Potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) Cultivars to Verticillium Wilt Caused by <Emphasis Type="Italic">Verticillium dahliae</Emphasis>

Verticillium wilt is a fungal disease of potato caused by two species of Verticillium, V. dahliae and V. albo atrum. The pathogen infects the vascular tissue of potato plants through roots, interfering with the transport of water and nutrition, and reducing both the yield and quality of tubers. We have evaluated the reaction of 283 potato clones (274 cultivars and nine breeding selections) to inoculation with V. dahliae under greenhouse conditions. A significant linear correlation (r = 0.4, p < 0.0001) was detected between plant maturity and partial resistance to the pathogen, with late maturing clones being generally more resistant. Maturity-adjusted resistance, that takes into consideration both plant maturity and resistance, was calculated from residuals of the linear regression between the two traits. Even after adjusting for maturity, the difference in the resistance of clones was still highly significant, indicating that a substantial part of resistance cannot be explained by the effect of maturity. The highest maturity-adjusted resistance was found in the cv. Navajo, while the most susceptible clone was the cv. Pungo. We hope that the present abundance of data about the resistance and maturity of 283 clones will help potato breeders to develop cultivars with improved resistance to V. dahliae.     

Genetic and Pathogenic Diversity of <Emphasis Type="Italic">Ralstonia solanacearum</Emphasis> Causing Potato Brown Rot in China

Causing potato brown rot, Ralstonia solanacearum (R. solanacearum) strains are reported as one of the most destructive bacteria to potato (Solanum tuberosum L.) in China. In this study, 113 strains were isolated from potato, collected in the four major agroecological zones in China. The study showed that 102 strains belonged to the phylotype IIB sequevar 1 (race 3 biovar 2). The 11 remaining strains belonged to the phylotype I, sequevar 13, 17, 18, 16 or 14 M, a new sequevar closely related to sequevar 14. Thirty-four strains were further characterized according to their virulence at low temperature on three wild potato species. IIB-1 strains all belonged to high and moderate virulence, while others belonged to the low virulence group, which had limited pathogenicity.     

A Greenhouse Assay for Powdery Scab (<Emphasis Type="Italic">Spongospora subterranea</Emphasis> f. sp. <Emphasis Type="Italic">subterranea</Emphasis>) Resistance in Potato

The plasmodiophorid pathogen Spongospora subterranea f. sp. subterranea causes powdery scab disease of potatoes (Solanum tuberosum L.), which severely affects tuber quality. Adequate chemical control of the disease is lacking, so breeding resistant potato cultivars is important. Little is known about the mechanisms or genetics of host resistance, as the epidemiology of the pathogen makes research on the disease difficult. An environmentally controlled disease screen that allows the accurate and repeatable assessment of diseased tubers (rather than a ranking system) is required to study host resistance in more detail. A high-throughput greenhouse disease assay is described that has been used to assess varying levels of tuber disease resistance of potato genotypes for three consecutive Southern Hemisphere growing seasons (2001–2002, 2002–2003, 2003–2004). This assay allows the evaluation of symptoms on tubers to verify resistance, rather than inferring the tuber infection on the basis of root galling or zoosporangial root infection. The assay was used to determine the level of resistance of genotypes of both known and unknown resistance status. The assay clearly distinguished the susceptible and resistant standards, and the results were highly correlated over the three seasons. The most efficient ways of assessing tuber disease susceptibility of genotypes are discussed. The consistency of the results and the ability to screen many genotypes confirms the value of the assay as a tool for early-generation selection in a plant breeding programme.     

<Emphasis Type="Italic">In vitro</Emphasis> and <Emphasis Type="Italic">In vivo</Emphasis> Antioxidant Properties of Extracts from <Emphasis Type="Italic">Coptis chinensis</Emphasis> Inflorescence

The inflorescence of cultivated Coptis chinensis has been valued for tea production for many years in China. The antioxidant activities of C. chinensis inflorescence extracts prepared by various solvents were investigated by using several established in vitro systems: 2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS), α,α-diphenyl-β-picrylhydrazyl (DPPH) and superoxide radical scavenging assays, reducing power assay, and ferrothiocyanate (FTC) and thiobarbituric acid (TBA) assays. The results showed that the 70% ethanol extract (EE) had the strongest antioxidant activity in vitro among the various extracts. Based on the in vitro results, EE was used to evaluate the antioxidant activity of C. chinensis inflorescence in vivo. The liver and kidney of intoxicated animals showed a significant decrease in superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) levels, while the malondialdehyde (MDA) level showed a significant increase. These changes were significantly reversed after treatment with EE and the standard vitamin E. Thus, the C. chinensis inflorescence may be a valuable natural source that can be applicable to food industries.     

Rooting Characteristics of <Emphasis Type="Italic">Solanum chacoense</Emphasis> and <Emphasis Type="Italic">Solanum tuberosum in Vitro</Emphasis>

The precise level of environmental control in vitro may aid in identifying genetically superior plant germplasm for rooting characteristics (RC) linked to increased foraging for plant nitrogen (N). The objectives of this research were to determine the phenotypic variation in root morphological responses of 49 Solanum chacoense (chc), 30 Solanum tuberosum Group Phureja – Solanum tuberosum Group Stenotomum (phu-stn), and three Solanum tuberosum (tbr) genotypes to 1.0 and 0.5 N rate in vitro for 28 d, and identify genotypes with superior RC. The 0.5 N significantly increased density of root length, surface area, and tips. All RC were significantly greater in chc than in either phu-stn or tbr. Based upon clustering on root length, surface area, and volume, the cluster with the greatest rooting values consisted of eight chc genotypes that may be utilized to initiate a breeding program to improve RC in potato.     

Bread Supplemented with Amaranth (<Emphasis Type="Italic">Amaranthus cruentus</Emphasis>): Effect of Phytates on <Emphasis Type="Italic">In Vitro</Emphasis> Iron Absorption

The objective of the present study was to evaluate the effect of the bread supplemented with whole amaranth flour (0, 20 and 40%) on iron bioavailability using Caco-2 cells model. The phytate and lower myo-inositol phosphates content in in vitro bread digests were measured by high pressure liquid chromatography. The breads made with amaranth showed significant increase of soluble phytates levels (up to 1.20 μmol/g in dry matter for the 40% of substitution) in comparison with controls, which have not detectable values. A negative correlation among phytate and Fe availability was found when increased levels of amaranth. Ferritin concentration was found 2.7- and 2.0-fold higher (P < 0.05) in cultures exposed to 20% and 40% of amaranth formulated bread samples, respectively, compared to control bread. The soluble phytate/Fe molar ratio explained the whole amaranth flour-mediated inhibitory effect associated to the limitation of available Fe; however, the use up to 20% of amaranth in bread formulation appears as a promising strategy to improve the nutritional value of bread, as indicated by the ferritin concentrations quantified in cell cultures. Higher proportion of amaranth flour increased Fe concentration although there was not detected any increase in Fe uptake.     

Resistance to <Emphasis Type="Italic">Meloidogyne chitwoodi</Emphasis> Identified in Wild Potato Species

Meloidogyne chitwoodi (Columbia root-knot nematode, CRKN) can cause serious damage in potato production systems, decreasing tuber value in the fresh market and processing industries. Genetic resistance to CRKN was first identified from the wild diploid potato species Solanum bulbocastanum accession SB22 and was successfully introgressed into tetraploid potato breeding material. To expand the base of genetic resistance, 40 plant accessions representing nine wild potato species were screened for their resistance to M. chitwoodi. Greenhouse screening identified fifteen clones from S. hougasii, one clone from S. bulbocastanum, and one clone from S. stenophyllidium with moderate to high levels of resistance against three isolates of M. chitwoodi. Geographical mapping showed that the resistance sources identified in this and previous studies primarily originated in the states of Jalisco and Michoacán in west-central Mexico. These new sources of resistance will be introgressed into elite potato populations to facilitate the development of potato cultivars with durable resistance to M. chitwoodi.     

Comparative Study of Lipophilic and Hydrophilic Antioxidants from <Emphasis Type="Italic">In vivo</Emphasis> and <Emphasis Type="Italic">In vitro</Emphasis> Grown <Emphasis Type="Italic">Coriandrum sativum</Emphasis>

Coriander is commonly used for medicinal purposes, food applications, cosmetics and perfumes. Herein, the production of antioxidants in vegetative parts (leaves and stems) of in vivo and in vitro grown samples was compared. In vitro samples were clone A- with notorious purple pigmentation in stems and leaves and clone B- green. Seeds were also studied as they are used to obtain in vivo and in vitro vegetative parts. Lipophilic (tocopherols, carotenoids and chlorophylls) and hydrophilic (sugars, ascorbic acid, phenolics, flavonols and anthocyanins) compounds were quantified. The antioxidant activity was evaluated by radical scavenging activity, reducing power and lipid peroxidation inhibition. The in vivo sample showed the highest antioxidant activity mainly due to its highest levels of hydrophilic compounds. Otherwise, in vitro samples, mainly clone A, gave the highest concentration in lipophilic compounds but a different profile when compared to the in vivo sample. Clones A and B revealed a lack of β-carotene, β- and δ-tocopherols, a decrease in α-tocopherol, and an increase in γ-tocopherol and clorophylls in comparison to the in vivo sample. In vitro culture might be useful to explore the plants potentialities for industrial applications, controlling environmental conditions to produce higher amounts of some bioactive products.     

Phenolic Composition,Antioxidant Capacity and <Emphasis Type="Italic">In Vitro</Emphasis> Cancer Cell Cytotoxicity of Nine Prickly Pear (<Emphasis Type="Italic">Opuntia</Emphasis> spp.) Juices

Juices of nine prickly pears (Opuntia spp.) were characterized in terms of color, acidity, sugar content, phenolics, flavonoids, betalains and antioxidant activity and tested in vitro against four cancer cell lines. The juices had pH′s, acidities and sugar ranging from 4.27 to 5.46, 0.03 to 0.27% and 8 to 14.7°Brix, respectively. Juices also varied in color from white to purple and contained total phenolics, flavonoids, betaxanthins, betacyanins and antioxidant capacity ranging from 22 to 226 μg gallic acid eq/g, 95 to 374 μg quercetin eq/g, 3 to 189 μg/g, 1.6 to 300 μg/g and 17 to 25 micromoles Trolox eq./mL, respectively. Among the cancer lines tested, viability of prostate and colon cells were the most affected. Moradillo contained the highest flavonoids and diminished both prostate and colon cancer cell viability without affecting mammary or hepatic cancer cells. Rastrero reduced the growth of the four cancer cell lines without affecting normal fibroblast viability. The research shows intervarietal differences among prickly pears in terms of juice properties and phytochemicals that could prevent oxidative stress and cancer.     

Enhanced <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">tuberosi</Emphasis> Resistance in Transgenic Potato Expressing a Rice GLP Superoxide Dismutase Gene

Germin like proteins (GLPs) are a large group of related and ubiquitous plant proteins which are considered to be involved in different processes important for plant development and defense. Multiple functional copies of this gene family have been reported in a number of species (wheat, barley, rice, soybean mosses and liverwort), and their role is being evaluated by gene regulation studies and transgenic approaches. To analyze the role of a rice (Oryza sativa) root expressed germin like protein1 OsRGLP1, for its antifungal activity, transgenic potato plants were developed. These transgenic potato plants were molecularly characterized and biologically assessed after inoculation with Fusarium oxysporum f. sp. tuberosi. Functional analysis showed high accumulation of H₂O₂, increased Superoxide Dismutase (SOD) activity and no oxalate oxidase activity (OxO) in transgenics in comparison to nontransformed control. This increased SOD activity, resistance to heat and sensitivity to H₂O₂ suggest it is a Fe-like SOD. OsRGLP1 expression in potato plants exhibited enhanced resistance in comparison to nontransformed wild type plants suggesting its role in providing protection against Fusarium oxysporum f. sp. tuberosi through elevated SOD level. Overall, results suggest that OsRGLP1 is a candidate for the engineering of potato plants with increased fungal tolerance however, the greater height and tuber number was observed. This phenotype associated with the resistance needs to be evaluated to determine if this is a positive or negative feature.     

<Emphasis Type="Italic">In vitro</Emphasis> Antioxidant Activity of Aged Extracts of some Italian <Emphasis Type="Italic">Allium</Emphasis> Species

Antioxidant activity of fresh Allium sativum L. (garlic) is well known and is mainly due to unstable and irritating organosulphur compounds. Fresh garlic extracted over a prolonged period (up to 20 months) produces odourless aged garlic extract (AGE) containing stable and water soluble organosulphur compounds that prevent oxidative damage by scavenging free radicals. The aim of this study was to investigate the in vitro antioxidant activity of aged (up to 20 months) 15% hydroethanolic extracts of different parts (bulbs, bulblets, flower bulblets, flowers, and leaves) of three Allium spontaneous species which are endemic for Italian flora: Allium neapolitanum Cyr., Allium subhirsutum L., Allium roseum L. and to compare it with the in vitro antioxidant activity of aged 15% hydroethanolic extracts of bulbs and leaves of garlic. The antioxidant potential of aged extracts of all species has been evaluated using two different spectrophotometric assays: 2,2-diphenylpicrylhydrazyl (DPPH) test and the ferric reducing/antioxidant power (FRAP) assay. Furthermore the polyphenol content was determined. The aged extracts obtained from the leaves showed the best antioxidant activity, followed by flowers and then by bulbs in both used tests, while flower bulblets and bulblets exhibited lower results or no activity. The polyphenol content was generally directly correlated with antioxidant/antiradical activity. This study confirms the data obtained in previous researches, the wild-type species of Allium and in particular organs other than bulbs are more active and efficacious than garlic bulb. Surely leaves of these Allium spp. deserve special attention.     

Yield Response of Potato (<Emphasis Type="Italic">Solanum tuberosum L</Emphasis>.) Genotypes to Late Blight Caused by <Emphasis Type="Italic">Phytophthora infestans</Emphasis> in Uganda

Potato (Solanum tuberosum L.) is a major food and cash crop, mainly grown by small-scale farmers in the highland regions of Uganda. Potato late blight is one of the major diseases limiting production with potential yield losses over 70%, making host resistance a strong element in integrated disease management. This study was carried out to screen and select high yielding potato genotypes with resistance to late blight in Uganda. Forty-eight genotypes, including advanced clones from the population B3C2 of the International Potato Centre, commercial and farmers’ varieties, were evaluated under two environments for two seasons. Trials were laid out in an 8?×?6 alpha lattice design with three replications. Genotypes showed significant differences in yield and resistance to blight. A higher disease severity was observed in Karengyere (56%). The average RAUDPC (= 100 max) across locations indicated that genotypes 395,077.12 and 392,657.8, with disease severity of 12% and 14%, respectively, were the most resistant. Genotypes Victoria (53%) and NKRN59.124 (48%) were the most susceptible. Mean tuber yield under late blight infection was19.8 t ha^?1. The best yielding genotype across sites was 395,112.32 (35.6 t ha^?1) while 394,905.8 (10.3 t ha^?1), yielded the lowest. The mean marketable tuber weight was 8.9 kg with genotypes 395,112.32 and 395,109.34 having the highest marketable weight of 16.5 kg and 15.6 kg respectively. Correlations between yield and yield related parameters were positive (p ≤?0.001), while those between RAUDPC were negative. The following genotypes, 395,112.32, 391,919.3, 393,220.54. 393,077.54, 396,038.107. 392,657.8, Kinigi, 395,014.17, NKRN59.58, NKRK19.17 and 395,011.2, were identified as promising parents for a late blight resistance breeding program. These exhibited high to medium resistance to late blight disease and high yields.     

<Emphasis Type="BoldItalic">In Vitro</Emphasis> Antioxidant and Anti-rhizopus Activities of Lamiaceae Herbal Extracts

Eighty-eight extracts of different polarity obtained from 18 Lamiaceae medicinal and aromatic plants were screened for their antioxidant and antifungal properties. A TLC analysis combined with two bioassays were used to detect these activities. In most cases the highest radical scavenger capacity was detected in methanolic and aqueous extracts and polyphenols may be responsible. The most interesting antioxidant activity was observed in polar extracts obtained from Lycopus europaeus, Melissa officinalis, Origanum vulgare subsp. virens and Lavandula latifolia. On the contrary, the best results for the antifungal test against Rhizopus stolonifer were produced by non-polar herbal extracts. Phlomis lychnitis, Salvia pratensis and Calamintha sylvatica caused the highest inhibition on Rhizopus growth.     

Antioxidative and Anticancer Activity of Extracts of Cherry (<Emphasis Type="Italic">Prunus serrulata</Emphasis> var. <Emphasis Type="Italic">spontanea</Emphasis>) Blossoms

Organic solvent (methanol, ethanol, and acetone) extracts and water extracts of cherry (Prunus serrulata var. spontanea) blossoms were prepared, and antioxidant activities of the extracts were evaluated. Methanolic CBE (100 μg/ml) showed the highest total phenol content (104.30 μM), radical scavenging activity (34.2%), and reducing power (0.391). The effect of CBE on DNA damage induced by H₂O₂ in human leukocytes was evaluated by Comet assay. All CBE was a potent dose dependent inhibitor of DNA damage induced by 200 μM of H₂O₂, methanolic CBE showed the most strong inhibition activity. The methanolic CBE of 500 μg/ml showed 38.8% inhibition against growth of human colon cancer cell line HT-29. These results indicated that cherry blossoms could provide valuable bioactive materials.     

Comparative Study on the Chemical Composition,Antioxidant Properties and Hypoglycaemic Activities of Two <Emphasis Type="Italic">Capsicum annuum</Emphasis> L. Cultivars (<Emphasis Type="Italic">Acuminatum</Emphasis> small and <Emphasis Type="Italic">Cerasiferum</Emphasis>)

The present study aimed to evaluate for the first time the phenols, flavonoids, carotenoids, capsaicin and dihydrocapsaicin content and the antioxidant and hypoglycemic properties of Capsicum annuum var. acuminatum small and C. annuum var. cerasiferum air-dried fruits. The ethanol extract of C. annuum var. acuminatum small, characterized by the major content of total poliphenols, flavonoids, carotenoids and capsaicinoids, showed the highest radical scavenging activity (IC₅₀ of 152.9 μg/ml). On the contrary, C. annuum var. cerasiferum showed a significant antioxidant activity evaluated by the β-carotene bleaching test (IC₅₀ of 3.1 μg/ml). The lipophilic fraction of both C. annuum var. acuminatum and C. annuum var. cerasiferum exhibited an interesting and selective inhibitory activity against α-amylase (IC₅₀ of 6.9 and 20.1 μg/ml, respectively).