Exploring the effects of ageing on instrumental and sensory characteristics of meat from Lidia breed females: A comparative study of two commercial types.

The aim of this study was to assess the influence of ageing on instrumental and sensory qualities in Longissimus thoracis et lumborum (LTL) from heifers (n = 200) and cows (n = 100) of Lidia breed. The animals were slaughtered as heifers (24-48 months) or cull cows (> 48 months). For instrumental analysis, pars Thoracis aged at 7, 14 and 28 days was used; for sensory analysis, pars Lumborum aged at 14 and 28 days was evaluated. Heifers showed redder and yellower meat (P < 0.05) and cows showed slightly higher Water Holding Capacity (WHC): Thawing Loss (TL) = P < 0.05; Drip Loss (DL) = P < 0.01; Pressure Loss (PL) = P < 0.01; Cooking Loss (CL) = P < 0.05. Ageing generated changes in meat colour, with increases in lightness (L*, linear pattern, P < 0.001) and oscillations in a* and b* (quadratic patterns; P < 0.05 and P < 0.001, respectively). Ageing affected TL (increasing, P < 0.001) and PL (decreasing, P < 0.05), and generated a significant improvement in Warner Bratzler Shear Force (WBSF) values (P < 0.001). Commercial type revealed changes in consumer panel ratings for flavour (P < 0.05), juiciness (P < 0.01), tenderness (P < 0.001) and overall acceptability (P < 0.001), with better results in these parameters for cull cows. In contrast to the usual, ageing did not affect the sensory traits. There was no significant interaction between commercial type and ageing time, except for beef flavour, which worsened with ageing (P < 0.05).

Carcass and Meat Quality Traits in Female Lidia Cattle Slaughtered at Different Ages.

The aim of this study was to assess the carcass and meat quality of female Lidia cattle slaughtered at different ages, in order to deepen our understanding of the breed's unique characteristics. The effect of slaughter age on carcass traits and meat quality attributes of m. Longissimus was investigated in Lidia heifers (n = 200) and cows (n = 100) reared and finished in an extensive system. The animals were slaughtered at 24-36 months (Heifer I), 36-48 months (Heifer II) or >48 months (Cull cow). The carcasses (~120 kg) presented poor conformation (O, O+) and medium fatness (2, 2+). The dissection of the 6th rib yielded mean values of 58.6%, 14.3% and 24.8% for lean, fat and bone, respectively. The cows had a higher proportion of dissectible fat (p < 0.05). Subcutaneous fat was classified as dark and yellowish, and meat (aged for 21 days) as dark (L* = 25.5), reddish (a* = 14.4) and moderately yellowish (b* = 12.9), with acceptable water-holding capacity (TL = 5.34%; DL = 0.97%; PL = 8.9%; CL = 22.1%) and intermediate tenderness (WBSF = 4.6 kg/cm2). The b* value of meat was higher (p < 0.05) in cull cows. The meat of cull cows was more yellowish (p < 0.05) and obtained higher scores for flavor (p < 0.05), juiciness p < 0.01), overall tenderness (p < 0.001) and overall acceptance (p < 0.001).

Mechanisms for plant growth promotion activated by Trichoderma in natural and managed terrestrial ecosystems.

Trichoderma spp. are free-living fungi present in virtually all terrestrial ecosystems. These soil fungi can stimulate plant growth and increase plant nutrient acquisition of macro- and micronutrients and water uptake. Generally, plant growth promotion by Trichoderma is a consequence of the activity of potent fungal signaling metabolites diffused in soil with hormone-like activity, including indolic compounds as indole-3-acetic acid (IAA) produced at concentrations ranging from 14 to 234 µg l-1, and volatile organic compounds such as sesquiterpene isoprenoids (C15), 6-pentyl-2H-pyran-2-one (6-PP) and ethylene (ET) produced at levels from 10 to 120 ng over a period of six days, which in turn, might impact plant endogenous signaling mechanisms orchestrated by plant hormones. Plant growth stimulation occurs without the need of physical contact between both organisms and/or during root colonization. When associated with plants Trichoderma may cause significant biochemical changes in plant content of carbohydrates, amino acids, organic acids and lipids, as detected in Arabidopsis thaliana, maize (Zea mays), tomato (Lycopersicon esculentum) and barley (Hordeum vulgare), which may improve the plant health status during the complete life cycle. Trichoderma-induced plant beneficial effects such as mechanisms of defense and growth are likely to be inherited to the next generations. Depending on the environmental conditions perceived by the fungus during its interaction with plants, Trichoderma can reprogram and/or activate molecular mechanisms commonly modulated by IAA, ET and abscisic acid (ABA) to induce an adaptative physiological response to abiotic stress, including drought, salinity, or environmental pollution. This review, provides a state of the art overview focused on the canonical mechanisms of these beneficial fungi involved in plant growth promotion traits under different environmental scenarios and shows new insights on Trichoderma metabolites from different chemical classes that can modulate specific plant growth aspects. Also, we suggest new research directions on Trichoderma spp. and their secondary metabolites with biological activity on plant growth.

In a belowground multitrophic interaction, Trichoderma harzianum induces maize root herbivore tolerance against Phyllophaga vetula.

BACKGROUND: Trichoderma spp. are soil fungi that interact with plant roots and associated biota such as other microorganisms and soil fauna. However, information about their interactions with root-feeding insects is limited. Here, interactions between Trichoderma harzianum and the root-feeding insect Phyllophaga vetula, a common insect pest in maize agroecosystems, were examined. RESULTS: Applications of T. harzianum and P. vetula to the root system increased and decreased maize growth, respectively. Induced tolerance against herbivore attack was provided by T. harzianum maintaining a robust and functional root system as evidenced by the increased uptake of Cu, Ca, Mg, Na and K. Herbivore tolerance also coincided with changes in the emission of root volatile terpenes known to induce indirect defense responses and attract natural enemies of the herbivore. More importantly, T. harzianum induced de novo emission of several sesquiterpenes such as ß-caryophyllene and δ-cadinene. In addition, single and combined applications of T. harzianum and P. vetula altered the sucrose content of the roots. Finally, T. harzianum produced 6-pentyl-2H-pyran-2-one (6-PP) a volatile compound that may act as an antifeedant-signaling compound mitigating root herbivory by P. vetula. CONCLUSION: Our results provide novel information about belowground multitrophic plant-microbe-arthropod interactions between T. harzianum and P. vetula in the maize rhizosphere resulting in alterations in maize phenotypic plant responses, inducing root herbivore tolerance.

Immediate impact of COVID-19 pandemic on farming systems in Central America and Mexico.

CONTEXT: The COVID-19 pandemic has affected all sectors and human activities around the World. OBJECTIVE: In this article we present a first attempt to understand the immediate impact of COVID-19 and the sanitary measures taken by governments on farming systems in Central America and Mexico (CAM). METHODS: Through a review of information generated in these initial months of the COVID-19 pandemic (webinars, blogs, electronic publications, media) and 44 interviews with key informants across the region, we have identified the main impacts felt by different types of farming systems in the region. RESULTS AND CONCLUSIONS: From corporate agricultural production systems, to small and medium scale entrepreneurs and smallholder subsistence farm households, all types of farming systems were impacted, more or less severely, by the different measures implemented by governments such as reduced mobility, closure of public and private venues and restrictions in borders. Larger corporate farming systems with vertical market integration and high level of control or coordination within the supply chain, and smallholder or subsistence farming systems with important focus on production for self-consumption and little external input use, were both relatively less impacted and showed greater adaptive capacity than the medium and small entrepreneurial farming systems dependent on agriculture as their primary income and with less control over the upstream and downstream parts of their supply chain. All types of farming systems implemented a series of mechanisms to cope with the COVID-19 pandemic including the development of alternative value chains, food and agricultural products delivery systems and the exponential use of digital means to communicate and maintain the viability of the different agricultural systems. Collective action and organization of farmers also proved to be an important coping mechanism that allowed some farmers to acquire inputs and deliver outputs in the context of restricted mobility, price volatility, and general uncertainty. Some features of the CAM region played an important role in mediating the impact of COVID-19 and associated sanitary measures. We identify as particularly relevant the nature of agricultural exports, the current structure of the agricultural sector, the diversified livelihood strategies of rural households, and the importance of mobility for rural livelihoods. SIGNIFICANCE: The results presented focus only in the immediate effect of COVID-19 pandemic and the mechanisms implemented by farmers in the first months. Whether these impacts and response mechanisms will result in a transformation of the farming systems towards greater resilience and sustainability is still an open question.

Increased maize growth and P uptake promoted by arbuscular mycorrhizal fungi coincide with higher foliar herbivory and larval biomass of the Fall Armyworm Spodoptera frugiperda.

Most plant species naturally associate with arbuscular mycorrhizal fungi (AMF), which are known to promote crop nutrition and health in agroecosystems. However, information on how mycorrhizal associations affect plant biotic interactions that occur aboveground with foliar herbivores is limited and needs to be further addressed for the development of pest management strategies. With the objective to examine the influence of maize mycorrhizas on foliar herbivory caused by larvae of Spodoptera frugiperda, a serious pest in maize agroecosystems, we performed a fully factorial greenhouse pot experiment with three factors: Maize genotype (Puma and Milpal H318), AMF (with and without AMF, and without AMF with mineral P) and Insect herbivory (with and without S. frugiperda). Main results showed that inoculation with AMF improved plant growth and foliar P concentration, which coincided with increased foliar damage from herbivory and higher biomass of S. frugiperda larvae. A significant positive correlation between shoot P concentration and larval biomass was also observed. Finally, foliar herbivory by S. frugiperda slightly increased and decreased AMF root colonization in Puma and H318, respectively. In conclusion, our results show that maize plant benefits from AMF in terms of promotion of growth and nutrition, and may also increase the damage caused from insects by improving the food quality of maize leaves for larval growth, which seems to be linked to increased P uptake by the maize mycorrhizal association.