Amine Elleuch

Drought is a major constraint on the productivity of durum wheat across Mediterranean and North African regions. To elucidate the mechanisms underlying drought resilience, we employed a combination of scenario-controlled phenomics and flag leaf transcriptomics across ten durum wheat genotypes. These included the Tunisian landraces Chili and Mahmoudi, seven breeding lines, and the reference cultivar Svevo. The plants were grown to maturity under well-watered or long-term drought conditions in pots and rhizotrons, enabling a comprehensive assessment of growth, yield components, root architecture, physiological traits, and reaction norm plasticity. Drought markedly reduced performance, yet Chili and Mahmoudi consistently maintained superior biomass, grain number and intrinsic water use efficiency (iWUE). This was supported by balanced C/N allocation, strong osmotic adjustment, and the ability to sustain robust root systems under stress, albeit through partly divergent physiological strategies. Transcriptomic profiling revealed highly genotype specific responses, with drought tolerance unrelated to the number of differentially expressed genes. Instead, the landraces displayed distinct regulatory programs involving mainly photosynthesis protection, ABA-related transporters, osmotic adjustment pathways, and stress-responsive transcription factors. These mechanistic insights identify actionable physiological and molecular determinants of drought plasticity and provide high value targets for accelerating the breeding of climate resilient durum wheat. Highlights: Integrated phenomics and transcriptomics revealed landrace-specific physiological and molecular mechanisms enabling superior drought resilience and identifying actionable targets for durum wheat improvement.

The reuse of treated municipal wastewater (TWW) in agriculture represents a sustainable solution to water shortages and constraints in agricultural production. However, poor monitoring of this water in Tunisia poses health risks for humans and environment. In this context, the TWW from the Thyna treatment plant in Sfax, is transported to the El Hajeb farm for irrigation, after undergoing primary and secondary treatments. This study aims to assess the feasibility and risks of reusing treated wastewater for irrigation in semi-arid regions by evaluating its impact on soil chemistry and microbiology under real farming conditions. To achieve this, three plots were selected for comparison: the first was supplied with treated wastewater (STWW), the second with well water (SWW), and the third was a control plot irrigated solely with rainwater (SRW). All these plots share the same soil types: Arenosol. The results revealed that TWW contained high concentrations of essential fertilizing elements, including nitrogen and other nutrients that enhance soil fertility. However, it also has significant amounts of sodium and chloride ions, contributing to soil salinization. Low levels of trace elements and very low levels of heavy metals were also detected. TWW was rich in microbial content, including bacteria such as FMAT, FC, TC, and YM, as well as pathogens like Escherichia coli and Salmonella spp. Microbiological results indicated soil quality deterioration due to pathogenic contamination. These findings suggest that the current treatment at the Sfax Thyna wastewater plant is insufficient to fully eliminate microbiological risks. To ensure safer irrigation practices and reduce health hazards, an additional tertiary treatment step is necessary.

Background/Objectives: The increased frequency of extreme weather events related to climate change, including the occurrence of extreme temperatures, severely affects crop yields, impairing global food security. Heat stress resulting from temperatures above 30 °C is associated with poor germination performance and stand establishment. The combination of climate-resilient crop genotypes and tailored seed priming treatments might represent a reliable strategy to overcome such drawbacks. This work explores the potential of hydropriming as a tool to mitigate the heat-stress-mediated impact on germination performance in orphan legumes. Methods: For each tested species (Lathyrus sativus L., Pisum sativum var. arvense and Trigonella foenum-graecum L.), two accessions were investigated. Germination tests were performed at 25 °C, 30 °C, 35 °C and 40 °C to assess the heat stress tolerance threshold. Hydropriming was then applied and germination tests were performed at 40 °C to test the impact of the treatment on the seeds’ ability to cope with heat stress. An alkaline comet assay and Quantitative Real Time-Polymerase Chain Reaction were performed on embryos excised from primed and control seeds. Results: Phenotyping at the germination and seedling development stage highlighted the accession-specific beneficial impact of hydropriming under heat stress conditions. In L. sativus seeds, the alkaline comet assay revealed the dynamics of heat stress-induced DNA damage accumulation, as well as the repair patterns promoted by hydropriming. The expression patterns of genes involved in DNA repair and antioxidant response were consistently responsive to the hydropriming and heat wave conditions in L. sativus accessions.

Lead stands as a food contaminant through its accumulation in consumed plants. In this study, the effects of lead (II) chloride (PbCl₂) and its levels of uptake on morphological and phytochemical responses of fenugreek were assessed to evaluate its tolerance and safety for human consumption. Results revealed that PbCl₂ (50–2000 mg L⁻¹) did not affect the germination rate, but it decreased the radicle length and amylase activity. After three months of Pb treatments, the elemental analysis showed that Pb accumulation was greater in roots than shoots, and it was not present in harvested seeds. The bioaccumulation factor > 1 and the translocation factor << 1 observed for 1000 mg L⁻¹ PbCl₂ suggested appropriateness of fenugreek as a phytostabilizer. Additionally, increased lipid peroxidation, hydrogen peroxide, flavonoid levels and catalase activity were observed in Pb-treated fenugreek. Meanwhile, decreased chlorophyll content was detected under these conditions. In turn, the total phenol was correlated with Pb treatment only in roots. HPLC analysis proved that under Pb stress, gallic acid was the most produced compound in treated roots compared to shoots, followed by quercetin. Syringic and chlorogenic acids were more produced in shoots. In conclusion, fenugreek can be used for Pb phytoremediation and is safe for consumption after Pb treatments in the traditional medicine system.

Context: Iron (Fe) is considered as a major cause of rural Tunisian soil contamination. Developing strategies for the cultivation of accumulator plants with permissible iron (Fe) concentrations is an urgent challenge. Aims: In this study, the effects of FeSO4 concentration (0, 50, 500 and 1000 mg L−1) on fenugreek morpho-biochemical parameters were investigated. Methods: The use of fenugreek as a phytoremediation strategy to control not only the uptake of Fe but also its safe consumption after treatments was evaluated. Key results: Results showed that elevated Fe concentrations did not affect the germination rate, but, rather, decreased the radicle length and amylase activity. The elemental analysis showed that Fe uptake was higher in shoots than in roots, but lower in harvested seeds. The translocation factor was higher than 1, suggesting a safe use of fenugreek as an accumulator. Moreover, the increase in Fe concentrations reduced the chlorophyll content and enhanced the production of lipid peroxidation, hydrogen peroxide and superoxide dismutase more frequently on fenugreek shoots than on their roots. In turn, the maximum concentrations of flavonoids and phenols were recorded under the Fe concentration of 50 mg L−1. High-performance liquid chromatography analysis showed that the gallic and syringic acids were the major phenols produced under Fe stress in shoots and that 50 mg L−1 of added Fe concentration induced their elevation. However, the quercetin was detected only in roots and was reduced under the increasing Fe concentrations. Conclusions: These results showed that fenugreek is an accumulator plant with admissible concentrations of Fe accumulation, which deploys multiple mechanisms to adapt to Fe stress.