Warm stratification combined with organic manure application enhances seed germination and improves Cycas revoluta growth and development

Cycas revoluta (Sago palm) is one of the widespread ornamental plant, used as an indoor and outdoor plant. Seed propagation is extremely hard and time consuming, given the physical dormancy imposed by hard coat. The use of warm stratification improves seed germination by prompting embryos development. As mean to gain more insight on the beneficial effect of warm treatment on seed germination, histological analysis of warm stratified and untreated embryos was conducted. Our results revealed that warm treatment accelerated embryos development, resulting in a rapid differentiation of embryos’ tissues. α-amylase, GA3 and ABA quantification showed that warm stratified embryos accumulated higher and lower amounts of α-amylase and ABA respectively compared to untreated embryos. Regarding plant development, our results showed that organic manures significantly improved Cycas revoluta growth and development. The best response was recorded with the application of sheep manure. Indeed, sheep manure addition increased plant height, the number of leaves per plant, stip length and width by nearby 188% and 61%, 36% and 17% respectively. In roots, the presence of nodules had been recorded in the three applied treatments and more importantly in the presence of sheep manure. At the physiological level, sheep manure supplementation improved photosynthetic apparatus and nitrogen content in leaves (by 75%), thereby explaining the growth promotion. Taken together, these results underlined the beneficial effect of organic manure on Cycas revoluta growth and development and proposed a new strategy to improve plant growth and development with the use of sheep manure as organic amendment

TomExpress, a unified tomato RNA-Seq platform for visualization of expression data, clustering and correlation networks

The TomExpress platform was developed to provide the tomato research community with a browser and integrated web tools for public RNA-Seq data visualization and data mining. To avoid major biases that can result from the use of different mapping and statistical processing methods, RNA-Seq raw sequence data available in public databases were mapped de novo on a unique tomato reference genome sequence and post-processed using the same pipeline with accurate parameters. Following the calculation of the number of counts per gene in each RNA-Seq sample, a communal global normalization method was applied to all expression values. This unifies the whole set of expression data and makes them comparable. A database was designed where each expression value is associated with corresponding experimental annotations. Sample details were manually curated to be easily understandable by biologists. To make the data easily searchable, a user-friendly web interface was developed that provides versatile data mining web tools via on-the-fly generation of output graphics, such as expression bar plots, comprehensive in planta representations and heatmaps of hierarchically clustered expression data. In addition, it allows for the identification of co-expressed genes and the visualization of correlation networks of co-regulated gene groups. TomExpress provides one of the most complete free resources of publicly available tomato RNA-Seq data, and allows for the immediate interrogation of transcriptional programs that regulate vegetative and reproductive development in tomato under diverse conditions. The design of the pipeline developed in this project enables easy updating of the database with newly published RNA-Seq data, thereby allowing for continuous enrichment of the resource

High-Temperature and Drought Stress Effects on Growth, Yield and Nutritional Quality with Transpiration Response to Vapor Pressure Deficit in Lentil

High temperature and water deficit are among the major limitations reducing lentil (Lens culinaris Medik.) yield in many growing regions. In addition, increasing atmospheric vapor pressure deficit (VPD) due to global warming causes a severe challenge by influencing the water balance of the plants, thus also affecting growth and yield. In the present study, we evaluated 20 lentil genotypes under field conditions and controlled environments with the following objectives: (i) to investigate the impact of temperature stress and combined temperature-drought stress on traits related to phenology, grain yield, nutritional quality, and canopy temperature under field conditions, and (ii) to examine the genotypic variability for limited transpiration (TRlim) trait in response to increased VPD under controlled conditions. The field experiment results revealed that high-temperature stress significantly affected all parameters compared to normal conditions. The protein content ranged from 23.4 to 31.9%, while the range of grain zinc and iron content varied from 33.1 to 64.4 and 62.3 to 99.3 mg kg−1 , respectively, under normal conditions. The grain protein content, zinc and iron decreased significantly by 15, 14 and 15% under high-temperature stress, respectively. However, the impact was more severe under combined temperature-drought stress with a reduction of 53% in protein content, 18% in zinc and 20% in iron. Grain yield declined significantly by 43% in temperature stress and by 49% in the combined temperature-drought stress. The results from the controlled conditions showed a wide variation in TR among studied lentil genotypes. Nine genotypes displayed TRlim at 2.76 to 3.51 kPa, with the genotypes ILL 7833 and ILL 7835 exhibiting the lowest breakpoint. Genotypes with low breakpoints had the ability to conserve water, allowing it to be used at later stages for increased yield. Our results identified promising genotypes including ILL 7835, ILL 7814 and ILL 4605 (Bakria) that could be of great interest in breeding for high yields, protein and micronutrient contents under high-temperature and drought stress. In addition, it was found that the TRlim trait has the potential to select for increased lentil yields under field water-deficit environment

Effect of High Temperature Stress During the Reproductive Stage on Grain Yield and Nutritional Quality of Lentil (Lens culinaris Medikus)

High temperature during the reproductive stage limits the growth and development of lentil (Lens culinaris Medikus). The reproductive and seed filling periods are the most sensitive to heat stress, resulting in limited yield and nutritional quality. Climate change causes frequent incidents of heat stress for global food crop production. This study aimed to assess the impact of high temperature during the reproductive stage of lentil on grain yield, nutritional value, and cooking quality. Thirty-six lentil genotypes were evaluated under controlled conditions for their high temperature response. Genotypic variation was significant (p < 0.001) for all the traits under study. High temperature-induced conditions reduced protein, iron (Fe) and zinc (Zn) concentrations in lentils. Under heat stress conditions, mineral concentrations among lentil genotypes varied from 6.0 to 8.8 mg/100 g for Fe and from 4.9 to 6.6 mg/100 g for Zn. Protein ranged from 21.9 to 24.3 g/100 g. Cooking time was significantly reduced due to high temperature treatment; the range was 3–11 min, while under no stress conditions, cooking time variation was from 5 to 14 min. Phytic acid variation was 0.5–1.2 g/100 g under no stress conditions, while under heat stress conditions, phytic acid ranged from 0.4 to 1.4 g/100 g. All genotypes had highly significant bioavailable Fe and moderately bioavailable Zn under no stress conditions. Whereas under heat stress conditions, Fe and Zn bioavailability was reduced due to increased phytic acid levels. Our results will greatly benefit the development of biofortified lentil cultivars for global breeding programs to generate promising genotypes with low phytic acid and phytic acid/micronutrient ratio to combat micronutrient malnutrition

Integrated microalgae-based biorefinery for wastewater treatment, industrial CO2 sequestration and microalgal biomass valorization: A circular bioeconomy approach

Microalgae are widely used in a variety of fields, including agriculture, the environment, medicine, cosmetics, food, and feed. They are used as feedstock for sustainably produced chemicals and biofuel. However, the production of microalgal-derived products is economically unprofitable. Integrated biorefinery based on microalgae-derived products is one of the long-term solutions that could be economically and environmentally viable with zero waste. This review emphasizes the integration of wastewater treatment with CO2 biosequestration from industrial flue gas and proposes an integrated biomass valorization strategy based on microalgae biorefineries. A model of integrated biorefinery with a techno-economic analysis and the possible microalgae-derived products that can be valorized after domestic wastewater and flue gas use as low-cost inputs for microalgae culture are also proposed

De Novo Transcriptome Assembly, Gene Annotations, and Characterization of Functional Profiling Reveal Key Genes for Lead Alleviation in the Pb Hyperaccumulator Greek Mustard (Hirschfeldia incana L.)

Lead (Pb) contamination is a widespread environmental problem due to its toxicity to living organisms. Hirschfeldia incana L., a member of the Brassicaceae family, commonly found in the Mediterranean regions, is characterized by its ability to tolerate and accumulate Pb in soils and hydroponic cultures. This plant has been reported as an excellent model to assess the response of plants to Pb. However, the lack of genomic data for H. incana hinders research at the molecular level. In the present study, we carried out RNA deep transcriptome sequencing (RNA-seq) of H. incana under two conditions, control without Pb(NO3)2 and treatment with 100 &micro;M of Pb(NO3)2 for 15 days. A total of 797.83 million reads were generated using Illumina sequencing technology. We assembled 77,491 transcript sequences with an average length of 959 bp and N50 of 1330 bp. Sequence similarity analyses and annotation of these transcripts were performed against the Arabidopsis thaliana nr protein database, Gene Ontology (GO), and KEGG databases. As a result, 13,046 GO terms and 138 KEGG maps were created. Under Pb stress, 577 and 270 genes were differentially expressed in roots and aboveground parts, respectively. Detailed elucidation of regulation of metal transporters, transcription factors (TFs), and plant hormone genes described the role of actors that allow the plant to fine-tune Pb stress responses. Our study revealed that several genes related to jasmonic acid biosynthesis and alpha-linoleic acid were upregulated, suggesting these components&rsquo; implication in Hirschfeldia incana L responses to Pb stress. This study provides data for further genomic analyses of the biological and molecular mechanisms leading to Pb tolerance and accumulation in Hirschfeldia incana L

Management of Plant Beneficial Fungal Endophytes to Improve the Performance of Agroecological Practices

By dint of the development of agroecological practices and organic farming, stakeholders are becoming more and more aware of the importance of soil life and banning a growing number of pesticide molecules, promoting the use of plant bio-stimulants. To justify and promote the use of microbes in agroecological practices and sustainable agriculture, a number of functions or services often are invoked: (i) soil health, (ii) plant growth promotion, (iii) biocontrol, (iv) nutrient acquiring, (v) soil carbon storage, etc. In this paper, a review and a hierarchical classification of plant fungal partners according to their ecosystemic potential with regard to the available technologies aiming at field uses will be discussed with a particular focus on interactive microbial associations and functions such as Mycorrhiza Helper Bacteria (MHB) and nurse plants

Étude métabolomique et biochimique de la tolérance et l'accumulation du Pb chez Hirschfeldia incana

International audiencePhytoremediation is an ecological method based on the use of tolerant and (hyper)accumulator plants to rehabilitate sites polluted by heavy metals. For a better use of these plants, a deep understanding of the mechanisms that control metal tolerance and accumulation is needed. The Brassicaceae Hirschfeldia incana grows naturally in contaminated sites. Under these conditions, it exhibits significant biomass and a high capacity for lead tolerance and accumulation (1; 2). To optimize its use in Pb phytoremediation processes, we analyzed the variation of metabolomic profile by GC-MS in H.incana plants treated with Pb for 3 and 15 days. The metabolomic analysis of the organic fraction of H.incana’s aerial part showed an increase in the concentration of organic acids since the first days of treatment and a decrease in the concentration of membrane lipids and steroids, thus revealing signs of toxicity in form of lipid peroxidation. On the other hand, after 15 days of treatment, an increase in the total concentration of lipids and steroids was reported, indicating a sort of adaptation of H.incana to Pb stress. A comparison of enzyme activities and MDA content between Pb-treated and untreated plants showed a decrease in peroxidase activity and a slight increase in catalase activity after 15 days of treatment. MDA content decreased after 3 days of treatment and then increased after 15 days of treatment. Our results suggest that the plant compensates lipid peroxidation by activating other lipid biosynthetic pathways which explain the augmentation of lipid amount in 15 days treated plants.La phytoremédiation est une méthode écologique basée sur l’utilisation des plantes tolérantes et (hyper)accumulatrices pour la réhabilitation des sites miniers pollués par les métaux lourds. Pour une meilleure utilisation de ces plantes, une connaissance approfondie des mécanismes qui contrôlent la tolérance et l’accumulation des métaux demeure nécessaire. La Brassicacée Hirschfeldia incana pousse naturellement dans les sites contaminés. Dans ces conditions, elle présente une biomasse importante et une forte capacité de tolérance et d’accumulation du plomb (1, 2). Afin d’optimiser son utilisation dans des procédés de phytoremédiation du plomb, nous avons analysé les variations du profil métabolomique par GC-MS des plantes d’H.incana traitées par le Pb pendant 3 et 15 jours. L’analyse métabolomique de la fraction organique de la partie aérienne d’H.incana a montré une augmentation de la concentration des acides organiques dès le début du traitement et une diminution de la concentration des lipides membranaires et des stéroïdes révélant ainsi des signes de toxicité. En revanche, la concentration des lipides et des stéroïdes a augmenté après 15 jours du traitement. Une comparaison des activités enzymatiques et de la teneur en MDA entre des plantes traitées et non traitées a montré une diminution de l’activité de peroxydase et une augmentation de l’activité de catalase après 15 jours du traitement. La teneur en MDA a diminué chez les plantes traitées pendant 3 jours et a augmenté après 15 jours du traitement. Ces résultats suggèrent que probablement la plante compense la dégradation des lipides par activation d’autres voies de biosynthèses des lipides

Étude métabolomique et biochimique de la tolérance et l'accumulation du Pb chez Hirschfeldia incana

International audiencePhytoremediation is an ecological method based on the use of tolerant and (hyper)accumulator plants to rehabilitate sites polluted by heavy metals. For a better use of these plants, a deep understanding of the mechanisms that control metal tolerance and accumulation is needed. The Brassicaceae Hirschfeldia incana grows naturally in contaminated sites. Under these conditions, it exhibits significant biomass and a high capacity for lead tolerance and accumulation (1; 2). To optimize its use in Pb phytoremediation processes, we analyzed the variation of metabolomic profile by GC-MS in H.incana plants treated with Pb for 3 and 15 days. The metabolomic analysis of the organic fraction of H.incana’s aerial part showed an increase in the concentration of organic acids since the first days of treatment and a decrease in the concentration of membrane lipids and steroids, thus revealing signs of toxicity in form of lipid peroxidation. On the other hand, after 15 days of treatment, an increase in the total concentration of lipids and steroids was reported, indicating a sort of adaptation of H.incana to Pb stress. A comparison of enzyme activities and MDA content between Pb-treated and untreated plants showed a decrease in peroxidase activity and a slight increase in catalase activity after 15 days of treatment. MDA content decreased after 3 days of treatment and then increased after 15 days of treatment. Our results suggest that the plant compensates lipid peroxidation by activating other lipid biosynthetic pathways which explain the augmentation of lipid amount in 15 days treated plants.La phytoremédiation est une méthode écologique basée sur l’utilisation des plantes tolérantes et (hyper)accumulatrices pour la réhabilitation des sites miniers pollués par les métaux lourds. Pour une meilleure utilisation de ces plantes, une connaissance approfondie des mécanismes qui contrôlent la tolérance et l’accumulation des métaux demeure nécessaire. La Brassicacée Hirschfeldia incana pousse naturellement dans les sites contaminés. Dans ces conditions, elle présente une biomasse importante et une forte capacité de tolérance et d’accumulation du plomb (1, 2). Afin d’optimiser son utilisation dans des procédés de phytoremédiation du plomb, nous avons analysé les variations du profil métabolomique par GC-MS des plantes d’H.incana traitées par le Pb pendant 3 et 15 jours. L’analyse métabolomique de la fraction organique de la partie aérienne d’H.incana a montré une augmentation de la concentration des acides organiques dès le début du traitement et une diminution de la concentration des lipides membranaires et des stéroïdes révélant ainsi des signes de toxicité. En revanche, la concentration des lipides et des stéroïdes a augmenté après 15 jours du traitement. Une comparaison des activités enzymatiques et de la teneur en MDA entre des plantes traitées et non traitées a montré une diminution de l’activité de peroxydase et une augmentation de l’activité de catalase après 15 jours du traitement. La teneur en MDA a diminué chez les plantes traitées pendant 3 jours et a augmenté après 15 jours du traitement. Ces résultats suggèrent que probablement la plante compense la dégradation des lipides par activation d’autres voies de biosynthèses des lipides