Antioxidant activity of a catechol derived from abietic acid

The demand for novel effective antioxidant-based drugs has led to the synthesis and evaluation of the antioxidant potential in several molecules derived from natural compounds. In this work the in vitro antioxidant activity of an abietic acid-derived catechol (methyl 11,12-dihydroxyabietate-8,11,13-trien-18-oate, MDTO) was evaluated. This substance, possessing important biological properties, is similar to carnosic acid, a natural antioxidant from rosemary or sage leaves. Aiming to understand the antioxidant activity of MDTO, the energetics of its O-H bond, using time-resolved photoacoustic calorimetry (TR-PAC), was investigated. On energetic grounds it is predicted that MDTO is a good free radical scavenger, although its activity is lower than that of quercetin, a very effective antioxidant, which was used for comparison. In agreement with these predictions, the DPPH(*) and ABTS(*+) radical scavenging activities are lower than those of quercetin. In addition, MDTO also reacts with HOCl, a powerful proinflammatory oxidant produced by activated neutrophils, and protects liposomes against iron-ascorbate-induced oxidation. The discussion of these results foresees potential applications of MDTO as an antioxidant.     

First report of Ectinogonia buquetti (Spin.) (Coleoptera: Buprestidae) in bioenergy plantations of Eucalyptus camaldulensis (Dehnh.) in Chile

Ectinogonia buquetti (Spin.) (Coleoptera, Buprestidae) was identified as the agent causing damage on a Eucalyptus camaldulensis (Dehnh.) bioenergy plantation. Damage affected the principal apex and upper lateral branches and loss of lateral branches on E. camaldulensis due to complete ring-barking. E. buquetti is a coleopteron native to Chile, it preferably feeds on the wood of native species. A total of 205 individuals, all adults were found; 45% of the plants presented some type of damage.     

Regulation of stony hard peach softening with ACC treatment

Controlling the rate of fruit softening in melting-flesh peaches is a primary goal of the fruit industry. Stony hard (SH) peach varieties lack the ability to synthesize 1-aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, which is required for fruit maturation. SH peaches thus have crisp flesh that remains firm during ripening. In this study, we developed a simple technique to stimulate fruit softening by a single spray application of ACC at a concentration of 10–20 mM, which was sufficient to allow ethylene synthesis and fruit softening. Higher concentrations of ACC increased ethylene production, and made the fruit softer. Ethylene synthesis was limited to the first 2–3 d after ACC treatment, after which fruit ceased softening and retained its remaining firmness. These results indicate that a single application of ACC solution can be used to regulate the process of fruit softening in SH peaches.     

Genetic architecture of adult plant resistance to leaf rust in a wheat association mapping panel

Leaf rust caused by Puccina triticina is one of the most destructive fungal diseases of wheat (Triticum aestivum). Adult plant resistance (APR) is an effective strategy to achieve long‐term protection from the disease. In this study, findings are reported from a genome‐wide association study (GWAS) using a panel of 96 wheat cultivars genotyped with 874 Diversity Arrays Technology (DArT) markers and tested for adult leaf rust response in six field trials. A total of 13 quantitative trait loci (QTL) conferring APR to leaf rust were identified on chromosome arms 1BL, 1DS, 2AS, 2BL, 2DS, 3BS, 3BL, 4AL, 6BS (two), 7DS, 5BL/7BS and 6AL/6BS. Of these, seven QTLs mapped close to known resistance genes and QTLs, while the remaining six are novel and can be used as additional sources of resistance. Accessions with a greater number of combined QTLs for APR showed lower levels of disease severity, demonstrating additive and significant pyramiding effects. All QTLs had stable main effects and they did not exhibit a significant interaction with the experiments. These findings could help to achieve adequate levels of durable resistance through marker‐assisted selection and pyramiding resistance QTLs in local germplasm.     

Diverse phytoplasmas associated with leguminous crops in Russia

A large scale survey of diseased legume plants (mainly clover and alfalfa in the Fabaceae family) was conducted from 2009 to 2013 in four Economic Regions of Russia, Northern (Arkhangelsk and Vologda oblast), Central (Moscow oblast), Volga (Samara oblast) and West Siberian (Novosibirsk oblast). The majority of infected clover plants exhibited symptoms typical of clover phyllody (CPh), clover yellow edge (CYE), or clover proliferation (CP), and infected alfalfa plants exhibited symptoms typical of alfalfa witches’-broom (AWB). Of 161 symptomatic plants from 22 different legume species, 103 tested positive for phytoplasma infection. Phytoplasmas belonging to four groups and six subgroups were detected, of which 31.1% were group 16SrI, with the majority belonging to subgroup 16SrI-C- (causal agent of CPh disease), two belonging to 16SrI-B and two group 16SrI phytoplasmas not identified to the subgroup level;47.6% were group 16SrIII, with the majority belonging to subgroup 16SrIII-B or 16SrIII-B variant (causal agent of CYE disease), and one strain belonging to16SrIII-F; 8.7% were subgroup 16SrVI-A (causal agent of CP and AWB diseases); 9.7% were subgroup 16SrXII-A (causal agent of AWB disease); and 2.9% were mixed infected with subgroups 16SrIII-B and 16SrI-C. The predominant phytoplasma species detected varied by region. In the Northern and Central Regions, the majority of the phytoplasmas detected belonged to subgroups 16SrI-C and 16SrIII-B. In the West Siberian and the Volga Regions, the phytoplasmas predominately detected belonged to subgroups 16SrVI-A and 16SrXII-A, respectively. Subgroup 16SrIII-F was detected in a single plant in the West Siberian Region and a mixed infection of 16SrIII-B and 16SrI-C was detected in three plants, one in the Northern Region and two in the Central Region. Eleven species of insects of the order Hemiptera, suborder Auchenorrhyncha, were collected from leguminous plants in the Moscow oblast of the Central Region. Euscelis incisus and Aphrodes bicinctus were the most prevalent species and may be potential phytoplasma vectors in the Central Region.     

Development of an Ideotype-Based Selection Tool for Native Tropical Tree Breeding by Smallholder Planters in Mexico’s Maya Forest

Tree planters of the Yucatan peninsula in México are mostly first-generation small-scale forest owners. As a consequence of the lack of a management plan, trees employed for plantations are currently produced without any traceability or genetic improvement protocol, resulting in the reduced quality and heterogeneity of established materials. Recently, the Mexican government published a law to force planters to reverse this situation through the initiation and operation of germplasm management and traceability programs within each physiographic sub-province. Thus, planters located in the “Campeche Karts sub-provenance” now need to select superior trees for plant production, provenance assays, and orchard establishment. As a reference for the improvement goals in this work, we developed a model ideotype tree and qualification tool based on a weight-free selection index to compare trees in established plantations to enable the effective selection of superior trees to be used as seed sources and as a starting population for genetic improvement programs. The tool presented here is easy to use by planters, requiring a very basic computer or smartphone to run a spreadsheet where simple morphometric evaluation are captured, trees are qualified in comparison to the ideotypic values of each parameter with the aid of common field equipment. When this tool was applied to individuals from two different plantations, the qualification methodology ranked the individuals, allowing for the selection of superior trees in a more robust way, in contrast to the use of parameters mostly based on price and driven by wood volume.     

Macronutrient accumulation dynamics in apple fruits

In this study, we assessed the macronutrient levels of apple fruits cv. “Golden Smoothee” by monitoring their fruit absorption rates (mg fruit^?1 day^?1) and accumulation patterns (mg fruit^?1) throughout fruit development. Nutrient accumulation was a continuous process throughout the growing season, with patterns of absorption rates varying according to the nutrients concerned. Calcium was chiefly absorbed by the fruit during the first developmental stage, while the greatest absorption rates of other macronutrients occurred later in fruit development (from the end of shoot growth until harvest). From these patterns, it would be desirable to reduce the supply natural calcium (Ca) antagonists, such as potassium (K), ammonium (NH⁴⁺), and magnesium (Mg), during the first part of fruit development in order to achieve a good Ca balance with other nutrients and, consequently, an optimum fruit quality. Knowing these nutrient absorption and accumulation patterns is essential for planning optimum nutrient supply and improving their influence on fruit quality.