Irregular precipitation and drought caused an increase in tree mortality rates in multiple forest biomes with alterations in both ecosystem services and carbon balance. Carob (Ceratonia siliqua) growth and production in arid and semi-arid ecosystems are likely affected by climate change-induced droughts. Understanding the physiological responses of drought-induced early-stage tree death and strategies to enhance drought tolerance and optimize growth will help tree improvement programs. Mycorrhizal inoculation has a pronounced impact on plant growth, water absorption, mineral nutrition, and protection from abiotic stresses. However, a better understanding of these complex interconnected cellular processes and arbuscular mycorrhizal fungi (AMF)-mediated mechanisms regulating drought tolerance in plants will enhance its potential application as an efficient approach for bio-amelioration of stresses. The objectives of this work were to elucidate the different effects of autochthone AMF on inorganic solute and water content uptakes, organic adjustments (sugar and proteins content), leaf gas exchange (stomatal conductance and efficiency of photosystems I and II), and oxidative damage of two contrasting ecotypes of carob seedlings: coastal (southern ecotype (SE)) and in-land (northern ecotype (NE)) under control (C), drought (by cessation of irrigation for 15 days (15D)), and recovery (R) conditions. Our findings showed that AMF promoted growth, nutrient content, and physiological and biochemical parameters in plants of both ecotypes during C, 15D, and R conditions. After four days of recovery, stomatal conductance (g_s), the maximum photochemical efficiency of PSII (F_v/F_m), water content, and plant uptake of mineral nutrients (P, K, Na, and Ca) were significantly higher in shoots of mycorrhizal (AM) than non-mycorrhizal (NM) control plants. Consequently, AMF reduced to a greater degree the accumulation of hydrogen peroxide (H₂O₂) and oxidative damage to lipid (malondialdehyde (MDA)) content in AM than NM plants in NE and SE, after recovery. Altogether, our findings suggest that AMF can play a role in drought resistance of carob trees at an early stage by increasing the inorganic solutes (P, K, Na, and Ca), water content uptake, organic solutes (soluble sugars and protein content), stomatal conductance, and defense response against oxidative damage during re-watering after drought stress.

This study investigated the effect of seaweed extract (SWE) sprays obtained from Ulva rigida on wheat plants (Triticum durum L., variety Karim) grown under salt stress conditions for six weeks. Three levels of NaCl (0, 34.22, 68.44 mM) and four different concentrations (0, 12.5, 25 and 50%) of Ulva rigida as a water extract were applied. The obtained results indicated that seaweed treated plants showed higher ability to tolerate salt stress (34.22 or 68.44 mM of NaCl) by a significant (p < 0.05) increase of plant growth and the photosynthetic pigment contents, compared to those of control (non-treated plants). Furthermore, there was a significant improvement in antioxidant enzyme activity, such as superoxide dismutase (SOD), isocitrate dehydrogenase (ICDH), glutathione peroxidase (GPx), glutathione reductase (GR) activities in the stressed plants, especially in those treated with 12.5% of SWE. Overall, our results suggest that the application of the Ulva rigida water extract could be used as a promising plant growth biostimulant for treating wheat plants under salinity stress.

Biological nitrogen fixation requires a large amount of phosphorus (P). However, most of the soils are P-deficient and the extensive use of P- chemical fertilizers constitute a serious threat to the environment. In this context, two field experiments were carried out to investigate the effect of co-inoculation of Mesorhizobium ciceri with phosphate solubilizing bacteria (PSB), Bacillus sp., and Enterobacter aerogenes, on chickpea as an alternative to chemical nitrogen (N) and phosphorous fertilizers in P-deficient soils in dry areas of Morocco. The results revealed that combined inoculation of chickpea with rhizobia and PSB showed a significant enhancement of chickpea nodulation, biomass production, yields and N, P, and protein content in grains as compared to single inoculation or single application of N or P. A significantly higher increase was obtained by inoculating chickpea with Mesorhizobium sp. MA72 combined with E. aerogenes P1S6. This combination allowed an enhancement of more than 270% in nodulation, 192% in shoot dry weight and 242% in grain yield. The effect of this combination was equivalent to the effect of combined application of N and P fertilizers. Formulation of biofertilizers based on tasted strains could be used for chickpea co-inoculation in P-deficient soils for an eco-friendly sustainable production of chickpea.

Background: Seaweed-derived extracts have gained popularity in agriculture as bioproducts with phytostimulatory effects on plant growth and development. Methods: This study assessed the effect of polysaccharide-enriched extracts (PEEs) derived from six Moroccan seaweeds on tomato growth, yield, and fruit quality. PPEs were applied to tomato plants as soil drench in a greenhouse experiment. Growth parameters including plant height (cm) and number of leaves, flowers, and flower buds were recorded every 15 days. Yield and quality parameters of the harvested fruits were also recorded after each harvest. Results: The obtained results showed that all PEEs improved the growth, yield, and fruit quality of treated tomato plants. According to principal component analysis, the presence of SO₄, galactose, glucose, and maltose in the characterized polysaccharides was closely associated with their effect on plant growth, yield, and fruit quality parameters. Conclusions: PEEs obtained from Gelidium crinale,Schizymenia dubyi, Fucus spiralis, and Bifurcaria bifurcata exhibited the highest biostimulant effects and could be used as bioproducts for improved tomato yield and fruit nutritional quality.

Prickly pear cactus (Opuntia ficus‐indica) is a medicinal plant that plays important economic and ecological roles in arid and semi-arid regions. This study aims to assess the effectiveness of arbuscular mycorrhizal fungi (AMF) inoculation isolated from O. ficus-indica rhizosphere and/or vermicompost supplementation on growth and biochemical properties of newly developed O. ficus-indica cladodes. The experiment was conducted in a greenhouse with four treatments: control, AMF inoculation and vermicompost application individually or in combination with AMF. After eight months of cultivation, the results showed that the application of AMF and/or vermicompost improved growth and stimulated mycorrhizal colonization. Treatments with AMF, vermicompost, and AMF + vermicompost treatments increased sugar and protein contents by 30, 55 and 67% and 21, 60 and 84%, respectively. In addition, these treatments improved the superoxide dismutase, catalase and polyphenol oxidase activities and total phenolics and flavonoids content. Consequently, the same treatments enhanced the inhibition of the free radical 2, 2-diphenyl-1- picrylhydrazyl (DPPH) activity by 58, 52 and 33%, respectively compared to control plants, which reflects the highest antioxidant activity. In conclusion, our findings suggest that AMF combined with vermicompost induced the greatest effect on the different parameters tested and could improve the growth and development of cactus plants.

Septoria tritici blotch (STB) of wheat, caused by the ascomycete Zymoseptoria tritici (formerly Mycosphaerella graminicola), is one of the most important foliar diseases of wheat. In Morocco, STB is a devastating disease in temperate wheat-growing regions, and the yield losses can exceed up to 50% under favorable conditions. The aims of this study were to identify sources of resistance to STB in Septoria Association Mapping Panel (SAMP), which is composed of 377 advanced breeding lines (ABLs) from spring bread wheat breeding program of ICARDA, and to identify loci associated with resistance to STB at seedling (SRT) as well as at the adult plant (APS) stages using genome-wide association mapping (GWAM). Seedling resistance was evaluated under controlled conditions with two virulent isolates of STB (SAT-2 and 71-R3) from Morocco, whereas adult plant resistance was assessed at two hot spot locations in Morocco (Sidi Allal Tazi, Marchouch) under artificial inoculation with a mixture of STB isolates. At seedling stage, 45 and 32 ABLs were found to be resistant to 71-R3 and SAT-2 isolates of STB, respectively. At adult plant stage, 50 ABLs were found to be resistant at hot spot locations in Morocco. Furthermore, 10 genotypes showed resistance in both locations during two cropping seasons. GWAM was conducted with 9,988 SNP markers using phenotypic data for seedling and the adult plant stage. MLM model was employed in TASSEL 5 (v 5.2.53) using principal component analysis and Kinship Matrix as covariates. The GWAM analysis indicated 14 quantitative trait loci (QTL) at the seedling stage (8 for isolate SAT-2 and 6 for isolate 71-R3), while 23 QTL were detected at the adult plant stage resistance (4 at MCH-17, 16 at SAT-17, and 3 at SAT-18). SRT QTL explained together 33.3% of the phenotypic variance for seedling resistance to STB isolate SAT-2 and 28.3% for 71-R3, respectively. QTL for adult plant stage resistance explained together 13.1, 68.6, and 11.9% of the phenotypic variance for MCH-17, SAT-17, and SAT-18, respectively. Identification of STB-resistant spring bread wheat germplasm in combination with QTL detected both at SRT and APS stage will serve as an important resource in STB resistance breeding efforts.