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To exploit the wealth of biologically active chemicals present in plants, we developed a bioactivity screening platform that encompasses a series of standardized bioassays, including in vitro, indoor pot and field tests. The analyses were executed by a consortium of research labs with complementary expertise in plant pathology, plant physiology and ecotoxicology. The results of this broad screening effort were collected in a searchable database and revealed a wide range of biostimulant and biopesticide activities. We present a case study of bioactive extracts from Belgian endive (Cichorium intybus) roots that are the byproduct of the vegetable "Belgian witloof" and from industrial Cichorium inulin production. Belgian endive extract (BEE) stimulated root and shoot growth of in vitro grown seedlings and ornamental cuttings and increased the yield of greenhouse grown sweet pepper. The extract consists of a complex mixture of (oligo)-saccharides, organic acids, amino acids and sugar alcohols. Further fractionations and factorial design experiments are conducted to identify the active ingredients. Mode of action studies revealed that BEE harbours hormone signalling acitivty and modulates peroxide levels in the treated plants. Collectively, the results demonstrate that a broad spectrum bioactivity screening platform is an effictive approach to identify crop waste extracts as a potential resource for the development of novel biostimulants.

Bacteria that produce aminocyclopropane carboxylic acid (ACC)-deaminase enzyme (ACCd) are plant-growth-promoting rhizobacteria (PGPR) that may mitigate stress damages by suppressing stress-induced ethylene accumulation in plant tissues. Objectives of this study were to examine whether a novel strain of Burkholderia may promote plant tolerance to drought stress and post-stress recovery and determine changes in metabolic profiles in leaves and roots in response to ACCd-bacteria inoculation that could be associated with the positive ACCd-bacteria effects in cool-season perennial grass species. Creeping bentgrass (Agrostis Stolonifera) (cv. ‘Penncross’) plants were inoculated with Burkholderia bacteria. Inoculated and non-inoculated plants were subjected to drought stress by withholding irrigation for 35 days to evaluate drought tolerance and then were re-watered for 15 days to examine post-stress recovery. The inoculated plants demonstrated increased turf quality, canopy density, and root growth during drought stress and more rapid recovery in turf growth upon re-watering. Metabolomic analysis demonstrated that leaf tissue of inoculated plants under drought stress had significantly higher levels of arginine-succinate, proline, allantoin, folic acid, and S-Adenosyl methionine (SAM) relative to the leaf tissues of non-inoculated plants, while for inoculated root tissues under drought stress, the highest fold changes were observed for asparagine, proline, allantoin, and riboflavin. Inoculation also resulted in increased carbohydrate levels under drought stress conditions, in comparison to non-inoculated plants, with leaf tissue of inoculated plants having higher levels of stachyose, glucose, raffinose, sucrose, and fructose than non-inoculated plants, while root tissue exhibited higher concentrations of arabinose, raffinose, and glucose. After 15 days of re-watering leaf tissue of inoculated plants demonstrated higher levels of phenylthylamine, arginino-succinate, riboflavin, and thymidine relative to non-inoculated plants, while root tissue of inoculated plants exhibited increases in of the content of methionine, alpha-ketoglutarate, S-Adenosyl methionine (SAM), and folic acid. Carbohydrates and osmoregulants were reduced in the leaves of inoculated plants during the recovery period as the plants returned to non-stress metabolic status and resumed growth, as indicated by lower levels of sucrose, sorbitol, arabitol, and proline relative to non-inoculated plants. These results provide insights into the metabolic changes associated with PGPR-mediated improvements in drought stress tolerance and post-drought recovery in creeping bentgrass.

We would like to present the biological activity of an extremely effective anti-senescence compound (MTU, [1-(2-methoxyethyl)-3-(1,2,3-thiadiazol-5yl)urea]) which delayed both age- and stress-induced senescence of wheat plants (Triticum aestivum L.). We show that MTU blocks the senescence process in wheat by enhancing the abundance of PSI supercomplex with LHCa antennae (PSI-LHCa) and promoting the cyclic electron flow (CEF) around PSI. We suppose that this rarely-observed phenomenon blocks the disintegration of photosynthetic complexes and supercomplexes as indicated by 2D electrophoresis. After MTU treatment we observed higher efficiency of both photosystems and higher cyclic electron flow, especially under drought stress conditions. This effect was then reflected by the faster growth rate of wheat in optimal conditions and under drought and heat stress. Our multiyear field trial analysis further shows that the treatment with 0.4 g/ha of MTU enhanced average grain yields of field-grown crops by 5-15 %. This effect can be attributed to improved photosynthesis but also to the higher nitrogen use efficiency, which we believe is a response of plants to enhanced carbon availability of MTU-treated plants in an attempt to balance the carbon:nitrogen ratio. Interestingly, the analysis of gene expression and hormone profiling confirms that MTU acts without the involvement of cytokinins or other phytohormones. MTU appears to be the only chemical reported to date to affect PSI stability and activity. Our results thus indicate a central role of PSI and CEF in the onset of senescence with implications in yield management in crop species.

Reducing the dose of applied fertilizers is a crucial theme in today's agriculture, given on one hand the product shortage and sky-high prices and on the other hand the need to use less chemical inputs to ensure more healthy and fair food systems. Sustainable fertilization management is essential to increase the overall performance of cropping systems by providing economically optimum nourishment to the crop while minimizing nutrient losses. Biologically active peptides are largely used as plant biostimulants for boosting crop growth, improving crop tolerance to abiotic stresses and fruit quality. Peptides are able to improve directly and indirectly FUE (Fertilizer Use Efficiency), by enhancing uptake and utilization of nutrients. Starting from the bioactive properties of selected vegetal peptides, a new generation of products combining NPKs water soluble fertilizers and vegetal peptides has been developed by Hello Nature. This new generation of products, mixing different technologies, optimizes FUE, simplifies and reduces costs of application safeguarding, at the same time, food security and profitability of farmers. NPKs water soluble fertilizers combined with vegetal peptides have been tested in several trials on herbaceous crops under controlled and open field conditions. Results of the trials revealed an enhancement of FUE (eg. up to 10% in soilless tomato) using NPKs water soluble fertilizers mixed with peptides compared to NPKs water soluble fertilizers. These innovative products allowed to increase yield and at the same time reduce the dose of fertilizers applied by on average 15%. LCA demonstrated that the application of NPKs water soluble fertilizers mixed with peptides led to a reduction of carbon foot printing associated with the production of 1 unit of edible products (e.g. tomato fruits).

Along with nitrogen, phosphorus (P) is the most important nutrient for plant development and productivity. Restrictions on the use of fertilizers and the increasingly limited phosphorus natural stocks lead to the need of alternative solutions. The improvement of the uptake in case of low availability of nutrients is one of the main activities exerted by plant biostimulant products. In some case plant biostimulant application increase P availability in the soil and improve P plant uptake. The effect and modality of action of MOLTRO, a product containing organic components of plant origin and Bacillus atrophaeus, a Plant Growth Promoting Rhizobacteria (PGPR), was evaluated on tomato (Solanum lycopersicum L.). Biometric and molecular parameters were measured on 4-weeks old plants grown under 3 different nutritional conditions: optimal, in absence of P and with a source of insoluble P. The B. atrophaeus P solubilization activity was also evaluated and Phosphorus Use Efficiency calculated. MOLTRO application led to a growth improvement and to an increase of phosphorus uptake by the plant. In addition, transcriptomics analyses, showed an overexpression of genes involved in phosphate transport and organic acid production (citric and malic acids) in treated plants. A metabarcoding analysis showed that the addition of MOLTRO does not significantly alter the tomato rhizosphere microbiote composition. Overall, the results suggest a potential action of MOLTRO in increasing P absorption, thus playing a key role in enhancing plant health and growth.