Coat protein-mediated protection to cucumber mosaic virus infections in cultivated tomato

Summary Cucumber mosaic virus (CMV) infections rank among the most devastating diseases in the commercial culture of tomato (Lycopersicon esculentum Mill.), for which suitable sources of natural resistance are not available. The concept of pathogen-derived resistance, however, offers an alternate approach to combat plant viral diseases by transformation of crops with nucleotide sequences derived from the viral genome. This report demonstrates the successful application of such a pathogen-derived resistance gene comprising the CMV coat protein (CP) gene, to generate protection to CMV infections in cultivated tomato. Transformation of an inbred tomato line with the CMV CP gene isolated from a subgroup I strain, engendered high levels of protection to various CMV strains, including a virulent strain causing lethal necrosis and a typical subgroup II strain. Moreover, when challenged by natural infection through aphid vectors in open field, levels of protection were largely maintained in hemizygous hybrids. In all, these results demonstrate that synthetic resistance genes based on the CMV CP gene make excellent sources of broad spectrum resistance to CMV infections for introgression into tomato breeding programs.     

Chilling injury in mango fruit peel: Cultivar differences are related to the activity of phenylalanine ammonia lyase

In mango (Mangifera indica) cv. Nam Dok Mai fruit, stored at 4 °C, peel browning occurred within 9 d, while no browning was found in cv. Choke Anan fruit stored at 4 °C for 30 d. During 6 d of shelf life at 27-28 °C, following various periods of low temperature storage, the peel browning in cv. Nam Dok Mai (if not yet maximal) became worse, whereas little browning was observed in cv. Choke Anan fruit. The pulp of the fruit of both cultivars did not show browning during the 4 °C storage, but the pulp of cv. Nam Dok Mai exhibited some browning during shelf life if the fruit had been stored at 4 °C for more than 18 d. Peel and pulp color were not correlated with total free phenolics. A high correlation coefficient was observed between peel browning and PAL activity in the peel, while a very low correlation was found with peel catechol oxidase activity. The browning in the pulp was not correlated with the measured enzyme activities. The data therefore show a relation between PAL activity in the peel and low temperature-induced peel browning.     

1-MCP extends the storage and shelf life of mangosteen (Garcinia mangostana L.) fruit

Mangosteen (Garcinia mangostana L.) fruit were harvested when the peel (pericarp) was light greenish yellow with scattered pinkish spots. Fruit were exposed to 1 μL L⁻¹ 1-methylcyclopropene (1-MCP) for 6 h at 25 °C and were then stored at 25 °C (control) or 15 °C. The 1-MCP treatment only temporarily delayed softening of the fruit flesh, during storage. Storage life, defined as the time until the pericarp was dark purple, was much longer in fruit stored at 15 °C than in fruit stored at 25 °C. It was also longer in 1-MCP treated fruit (storage life at 15 °C: control 18 d, 1-MCP-treated fruit 27 d). The 1-MCP treatment also increased the length of shelf life, defined as the time until the pericarp turned blackish purple or showed calyx wilting, at 25 °C. 1-MCP treatment reduced ethylene production. It also reduced pericarp levels of 1-aminocyclopropane-1-carboxylic acid (ACC), and the pericarp activities of ACC synthase (ACS) and ACC oxidase (ACO). In the fruit flesh, in contrast, 1-MCP did not affect ACC levels and ACS activity, but the treatment reduced ACO activity. Taken together, both the storage life and the shelf life of the fruit were extended by the 1-MCP treatment. A decrease in ACO activity largely accounted for the effects of the 1-MCP on ethylene production in the pericarp.     

Surface runoff and seed trapping efficiency of shrubs in a regenerating semiarid woodland in northern Ethiopia

In forest restoration areas in northern Ethiopia, natural regeneration of Olea europaea ssp. cuspidata only occurs under pioneer shrubs. To assess the impact of erosion on the spatial distribution of Olea recruits, secondary dispersal of olive seeds by surface runoff was determined in and near the micro-environment of two important pioneers (Acacia etbaica and Euclea racemosa). We hypothesized that (1) Olea seeds deposited under the protective crowns of shrubs are less likely to be lost by surface wash than seeds in the bare inter-plant areas and (2) that seeds in the latter are more prone to be translocated by runoff to microsites under shrubs than to open areas.     

Hyperspectral waveband selection for automatic detection of floral pear buds

Thinning of fruit-tree blossoms is used to regulate the yearly tree bearing and to increase the fruit yield and quality. While this is still mostly done by hand, the increasing costs of manual labor have created a demand for mechanization. This has recently led to the development of several prototype thinning machines. The main disadvantage of these machines is that they are not selective, while the fruit bearing capacity of different floral buds is not equal. On-line information about the position and distribution of the floral buds on the tree can improve the efficiency of mechanized thinning. Therefore, the aim of this study was to identify the most informative wavebands to develop a multispectral vision sensor for detection of the floral buds of the pear cultivar Conference. Hyperspectral scans were taken from tree samples in five early phenological stages to create a database of reflectance spectra for the different tree features. A stepwise algorithm was then applied to this training set to select the best combination of wavebands having the highest discriminating power between the components of interest. Subsequently, canonical correlation analysis was used to create discriminant functions out of the selected wavebands. It was possible to correctly classify 95 % of the (pixel) observations with six selected wavebands. The discrimination performance was also tested as a function of the number of used wavebands. Analysis showed that when only the two most important wavebands were used, still over 90 % of the (pixel) observations could be correctly classified.     

Equine exudative canker: an (auto-)immune disease?

Equine canker is a chronic, hyperplastic, exudative pododermatitis affecting one or more feet. Although many causes and treatments have been suggested, the cause of the disease is still unknown and most probably multifactorial. Local treatments include radical surgical debridement of the diseased hoof tissue and application of caustic substances, antibiotics, and pressure bandaging. Nevertheless, the number of recurrences is high (45%). This article presents a 3-year-old New Forest pony-cross mare in which all horny structures (frogs, coronets, spurs, chestnuts) of all feet were affected. Bacteriological and fungal cultures of the frogs were found negative for the pathogens tested. Papilloma virus was not found. Clinical findings raised the hypothesis that the non-specific hyperplastic inflammation of these horn-like structures might have been caused by an (auto-)immune reaction. On the basis of the clinical findings, the pony was treated with surgical debridement of the frogs of a diagonal pair of feet and oral administration of prednisolone (1 mg/kg sid). The frogs, coronets, spurs, and chestnuts of all four feet healed completely within 8 weeks, thus making an (auto-)immune reaction more likely. In conclusion, this case report raised the hypothesis that an aspecific, hyperplastic inflammation of all four feet ('equine canker') and other horny structures may be caused by an (auto-)immune reaction, and that corticosteroids (prednisolone 1 mg/kg sid per os) are effective as treatment.     

Susceptibility of the tomato mutant high pigment-2dg (hp-2dg) to Orobanche spp. infection

The consumption of natural products with potential health benefits has been continuously growing, and enhanced pigmentation is of major economic importance in fruits and vegetables. The tomato hp-2 ( dg ) is an important mutant line that has been introgressed into commercial tomato cultivars marketed as lycopene rich tomatoes (LRT) because of their enhanced fruit pigmentation, attributed to higher levels of carotenoids, including lycopene. Strigolactones are signaling compounds that mediate host finding in root parasitic plants and are biosynthetically derived from carotenoids. Considering the high carotenoid content of the hp-2 ( dg ) mutant, we studied its susceptibility to the root parasite Orobanche. In a field experiment, the average number of Orobanche aegyptiaca plants growing on hp-2 ( dg ) was surprisingly significantly reduced compared with its isogenic wild-type counterpart. In vitro assays and LC-MS/MS analysis showed that this reduction was associated with a lower production of strigolactones, which apparently renders the high-carotenoid hp-2 ( dg ) mutant less susceptible to Orobanche.     

Bioavailability and kinetics of sulforaphane in humans after consumption of cooked versus raw broccoli

The aim of this study was to determine the bioavailability and kinetics of the supposed anticarcinogen sulforaphane, the hydrolysis product of glucoraphanin, from raw and cooked broccoli. Eight men consumed 200 g of crushed broccoli, raw or cooked, with a warm meal in a randomized, free-living, open cross-over trial. Higher amounts of sulforaphane were found in the blood and urine when broccoli was eaten raw (bioavailability of 37%) versus cooked (3.4%, p ) 0.002). Absorption of sulforaphane was delayed when cooked broccoli was consumed (peak plasma time ) 6 h) versus raw broccoli (1.6 h, p ) 0.001). Excretion half-lives were comparable, 2.6 and 2.4 h on average, for raw and cooked broccoli, respectively (p ) 0.5). This study gives complete kinetic data and shows that consumption of raw broccoli results in faster absorption, higher bioavailability, and higher peak plasma amounts of sulforaphane, compared to cooked broccoli.