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Aims: Since producing more with less is required for increasing agricultural sustainability and reducing its environmental impact, breeding varieties with increased yield stability under reduced fertilizer application is an important goal, particularly in high valued horticultural crops such as tomato (Solanum lycopersicum L.). However, because of the difficulties to conciliate yield and fertilizer use efficiency through breeding, the graft-compatible genetic biodiversity existing in horticultural species offers the possibility to directly approach this objective in high-yielding elite varieties through improving nutrient capture and promoting ecosystem services such as insect pollination. We hypothesized that rootstocks affect pollinator foraging decisions through the nutritional status that impacts yield. Methods: Fifteen genetically diverse experimental rootstocks were grafted to a scion tomato variety and cultivated under optimal and reduced (25% of optimal) P and NPK fertilization in the presence of managed bumblebee pollinators (Bombus terrestris). Results: Up to twofold yield variability between rootstocks was associated with leaf nutrition and photosynthesis of the scion. Interestingly, fertilization regime and the rootstock genotype influenced the pollinator foraging decisions since bumblebees showed feeding preference for plants cultivated under low P, and for the most yielding and nutritious graft combinations under reduced but not under optimal fertilization. Bumblebees can sense plant nutritional status through source-sink relations, as supported by the consistent relationship between pollinator preferences and leaf carbon concentration. Conclusions: This study opens new perspectives for using pollinators as "phenotypers" to select the most resilient plants under suboptimal conditions and/or genotypes that synergistically increase crop productivity by promoting the ecosystem service provided by the insects. [ABSTRACT FROM AUTHOR]

To determine whether root‐supplied ABA alleviates saline stress, tomato (Solanum lycopersicum L. cv. Sugar Drop) was grafted onto two independent lines (NCED OE) overexpressing the SlNCED1 gene (9‐cis‐epoxycarotenoid dioxygenase) and wild type rootstocks. After 200 days of saline irrigation (EC = 3.5 dS m−1), plants with NCED OE rootstocks had 30% higher fruit yield, but decreased root biomass and lateral root development. Although NCED OE rootstocks upregulated ABA‐signalling (AREB, ATHB12), ethylene‐related (ACCs, ERFs), aquaporin (PIPs) and stress‐related (TAS14, KIN, LEA) genes, downregulation of PYL ABA receptors and signalling components (WRKYs), ethylene synthesis (ACOs) and auxin‐responsive factors occurred. Elevated SlNCED1 expression enhanced ABA levels in reproductive tissue while ABA catabolites accumulated in leaf and xylem sap suggesting homeostatic mechanisms. NCED OE also reduced xylem cytokinin transport to the shoot and stimulated foliar 2‐isopentenyl adenine (iP) accumulation and phloem transport. Moreover, increased xylem GA3 levels in growing fruit trusses were associated with enhanced reproductive growth. Improved photosynthesis without changes in stomatal conductance was consistent with reduced stress sensitivity and hormone‐mediated alteration of leaf growth and mesophyll structure. Combined with increases in leaf nutrients and flavonoids, systemic changes in hormone balance could explain enhanced vigour, reproductive growth and yield under saline stress. ABA overproducing tomato rootstocks increase shoot vigour and fruit yield under saline conditions by altering stress‐related responses, improving photosynthesis and optimizing source‐sink relationships. [ABSTRACT FROM AUTHOR]

Teak (Tectona grandis) is one of the most important wood sources, and it is cultivated in tropical regions with a significant market around the world. Abiotic stresses are an increasingly common and worrying environmental phenomenon because it causes production losses in both agriculture and forestry. Plants adapt to these stress conditions by activation or repression of specific genes, and they synthesize numerous stress proteins to maintain their cellular function. For example, APETALA2/ethylene response factor (AP2/ERF) was found to be involved in stress signal transduction. A search in the teak transcriptome database identified an AP2/ERF gene named TgERF1 with a key AP2/ERF domain. We then verified that the TgERF1 expression is rapidly induced by Polyethylene Glycol (PEG), NaCl, and exogenous phytohormone treatments, suggesting a potential role in drought and salt stress tolerance in teak. The full-length coding sequence of TgERF1 gene was isolated from teak young stems, characterized, cloned, and constitutively overexpressed in tobacco plants. In transgenic tobacco plants, the overexpressed TgERF1 protein was localized exclusively in the cell nucleus, as expected for a transcription factor. Furthermore, functional characterization of TgERF1 provided evidence that TgERF1 is a promising candidate gene to be used as selective marker on plant breeding intending to improve plant stress tolerance. [ABSTRACT FROM AUTHOR]

Plant hormones are important in the control of physiological and developmental processes including seed germination, senescence, flowering, stomatal aperture, and ultimately the overall growth and yield of plants. Many currently available methods to quantify such growth regulators quickly and accurately require extensive sample purification using complex analytic techniques. Herein we used ultra-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) to create and validate the prediction of hormone concentrations made using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectral profiles of both freeze-dried ground leaf tissue and extracted xylem sap of Japanese knotweed (Reynoutria japonica) plants grown under different environmental conditions. In addition to these predictions made with partial least squares regression, further analysis of spectral data was performed using chemometric techniques, including principal component analysis, linear discriminant analysis, and support vector machines (SVM). Plants grown in different environments had sufficiently different biochemical profiles, including plant hormonal compounds, to allow successful differentiation by ATR-FTIR spectroscopy coupled with SVM. ATR-FTIR spectral biomarkers highlighted a range of biomolecules responsible for the differing spectral signatures between growth environments, such as triacylglycerol, proteins and amino acids, tannins, pectin, polysaccharides such as starch and cellulose, DNA and RNA. Using partial least squares regression, we show the potential for accurate prediction of plant hormone concentrations from ATR-FTIR spectral profiles, calibrated with hormonal data quantified by UHPLC-HRMS. The application of ATR-FTIR spectroscopy and chemometrics offers accurate prediction of hormone concentrations in plant samples, with advantages over existing approaches. [ABSTRACT FROM AUTHOR]

(1) Background: Peach cv. GF305 is commonly used in breeding programs due to its susceptibility to numerous viruses. In this study, we aimed to achieve a methodology for rapid and uniform seed germination of peach cv. GF305 in order to obtain vigorous seedlings; (2) Methods: A combination of cold stratification and H2O2 imbibition was tested on peach seeds with or without endocarp. In addition, the levels of non-enzymatic antioxidants ascorbate and glutathione as well as the hormone profile in seedling roots and shoots were determined; (3) Results: We found that H2O2 imbibition of peach seeds without endocarp after 8 weeks of stratification increased germination rate and resulted in seedlings displaying good vegetative growth. The H2O2 imbibition also affected the levels of ascorbate, glutathione, and the phytohormones abscisic acid and jasmonic acid in peach seedlings; (4) Conclusions: Although stratification periods of 12 weeks have been previously established as being appropriate for this cultivar, we have been able to reduce this stratification time by up to 4 weeks, which may have practical implication in peach nurseries. [ABSTRACT FROM AUTHOR]

Plants have remarkable regenerative capacity, which allows them to survive tissue damage after exposure to biotic and abiotic stresses. Some of the key transcription factors and hormone crosstalk mechanisms involved in wound-induced organ regeneration have been extensively studied in the model plant Arabidopsis thaliana. However, little is known about the role of metabolism in wound-induced organ formation. Here, we performed detailed transcriptome analysis and used a targeted metabolomics approach to study de novo organ formation in tomato hypocotyl explants and found tissue-specific metabolic differences and divergent developmental pathways. Our results indicate that successful regeneration in the apical region of the hypocotyl depends on a specific metabolic switch involving the upregulation of photorespiratory pathway components and the differential regulation of photosynthesis-related gene expression and gluconeogenesis pathway activation. These findings provide a useful resource for further investigation of the molecular mechanisms involved in wound-induced organ formation in crop species such as tomato. [ABSTRACT FROM AUTHOR]

Plants have a remarkable regenerative capacity, which allows them to survive tissue damage after biotic and abiotic stresses. In this study, we use Solanum lycopersicum 'Micro-Tom' explants as a model to investigate wound-induced de novo organ formation, as these explants can regenerate the missing structures without the exogenous application of plant hormones. Here, we performed simultaneous targeted profiling of 22 phytohormone-related metabolites during de novo organ formation and found that endogenous hormone levels dynamically changed after root and shoot excision, according to region-specific patterns. Our results indicate that a defined temporal window of high auxin-to-cytokinin accumulation in the basal region of the explants was required for adventitious root formation and that was dependent on a concerted regulation of polar auxin transport through the hypocotyl, of local induction of auxin biosynthesis, and of local inhibition of auxin degradation. In the apical region, though, a minimum of auxin-to-cytokinin ratio is established shortly after wounding both by decreasing active auxin levels and by draining auxin via its basipetal transport and internalization. Cross-validation with transcriptomic data highlighted the main hormonal gradients involved in wound-induced de novo organ formation in tomato hypocotyl explants. [ABSTRACT FROM AUTHOR]