Enhancing the sustainability of faba bean (Vicia faba L.) cultivation in Algerian oasis agroecosystems using drought-tolerant rhizobacteria

Soil Microbiota-Mediated Effects on Soybean (Glycine max (L.) Merr.) Growth and Yield: The Role of Bradyrhizobium japonicum and Trichoderma in Sustainable Agricultural Systems

Soybean (Glycine max (L.) Merr.) is a key legume with high agronomic and nutritional value, widely cultivated for its high-protein seeds and its capability to improve soil fertility through biological nitrogen fixation. Recently, co-inoculation strategies combining Rhizobia bacteria with growth-enhancing fungi from the genus Trichoderma have gained increasing attention as a way to enhance soybean productivity and resilience under variable environmental conditions. The present study, conducted in 2023–2024, examined how seed inoculation treatments (Bradyrhizobium japonicum and Trichoderma viride) affect soybean productivity, seed quality, and soil biochemical changes expressed as the activity levels of selected soil enzymes—dehydrogenases (DHA), catalase (CAT), acid phosphatase (ACP), and alkaline phosphatase (ALP)—as well as the biological fertility index (BIF). The findings indicated that co-inoculation positively influenced plant productivity and produced the highest seed yields among all treatments tested, exceeding the control by 25.6%. Furthermore, inoculated seeds were characterized by improved seed quality, expressed by higher germination capacity (80%) and greater average seedling length (4.74 cm). The bacterial strains used to inoculate soybean seeds increased soil biochemical activity and improved fertility, particularly under unfavorable rainfall distribution during the growing season. Co-inoculation can be recommended as an effective and environmentally friendly element of soybean cultivation technology, supporting yield stability in variable weather conditions. Further research is recommended in longer multi-year series and under various habitat conditions.

Rhizobium spp. strains improve the physiological attributes of Mimosa tenuiflora (Willd.) Poiret seedlings under different water contents

Rhizobium spp. inoculation is a strategy to promote plant growth and enhance drought tolerance, particularly in semiarid environments. This study evaluated the morphological and physiological responses of Mimosa tenuiflora (Willd.) seedlings inoculated with Rhizobium spp. under different water contents. Seeds were collected from 12 naturally growing mother trees (Patos, Paraíba, Brazil). No specific genotype or cultivar was used. A completely randomized experiment was conducted in a 5 × 2 factorial design with four replicates, comprising five treatments (inoculation with three Rhizobium spp. strains: CA19PT, RO19PT, and MK17PT; nitrogen fertilization; and a non-inoculated control) under two water-content levels (40% and 80% of pot capacity). M. tenuiflora seedlings were grown in 3 dm³ pots for 90 days, after which growth, biomass production, nodulation, relative water content (RWC), and gas exchange parameters were evaluated. The results demonstrated that physiological variables were influenced by the treatments and water availability, whereas growth variables were affected only by water availability. Among the evaluated treatments, inoculation with strain CA19PT showed physiological responses comparable to those observed under nitrogen fertilization. Even under low water availability (40% pc, seedlings maintained adequate hydration levels, with an increase in root biomass. Inoculation with selected Rhizobium isolates, particularly CA19PT, improved the physiological performance of M. tenuiflora seedlings under contrasting water-content conditions. Physiological responses observed in seedlings inoculated with CA19PT were comparable to those obtained with nitrogen fertilization. Additionally, seedlings grown under higher water content (80% pc exhibit better overall growth, whereas reducing water content to 40% pcstimulates root growth.

Genotype-Specific Root System Remodeling of Paspalum spp. Induced by Plant Growth-Promoting Bacteria Enhances the Potential for Sustainable Tropical Pastures

Brazilian cattle production relies predominantly on pasture systems, many of which are degraded by nutrient depletion, particularly nitrogen deficiency. Plant growth-promoting bacteria (PGPB) offer a sustainable strategy to improve pasture productivity, but their effects are often host-specific and remain poorly explored in Paspalum. This study evaluated the effect of inoculation with Azospirillum brasilense strains CNPSo 2083 (=Ab-V5) and CNPSo 2084 (=Ab-V6) and Pseudomonas fluorescens strain CNPSo 2719 (=CCTB 03), applied by seed inoculation or leaf spray, on the root morphology and shoot growth of four Paspalum accessions under controlled axenic greenhouse conditions, evaluated in an early growth stage at 35 days after emergence. Genotype-specific responses were the central finding of this study: Paspalum malacophyllum BGP-293 showed negligible responses to inoculation, whereas BGP-486—of the same species—increased root dry weight by up to 43% and root tissue density by up to 30% in all inoculated treatments. In Paspalum regnellii BGP-112, seed inoculation produced stronger root responses than foliar spray, increasing root dry weight by up to 38% and root area by up to 40%. In Paspalum rojasii BGP-149, inoculation induced root architectural remodeling without increasing root biomass—root area increased by up to 92% and total root length by up to 97%, relative to the control—indicating an efficient root-foraging strategy. P. fluorescens favored root-foraging traits and tissue density, whereas A. brasilense preferentially stimulated root-hair elongation. These accession-level contrasts, rather than a single generalizable trend, are the main contribution of this work: they support tailored, genotype-specific PGPB strategies for sustainable tropical pastures.

Evaluation of Drought Tolerance in In Vitro potato (Solanum tuberosum L.) cv. Dayang Sumbi Plantlets Using Polyethylene Glycol (PEG) 6000

Potato (Solanum tuberosum L.) is an important food crop whose productivity tends to decline under drought stress conditions. Water deficit limits water uptake, reduces cell turgor pressure, and disrupts photosynthesis, resulting in inhibited plant growth. Development of drought-tolerant potato cultivars can be achieved through in vitro culture using polyethylene glycol (PEG) 6000 as a selective agent that lowers the water potential of the culture medium without causing direct damage to plant cells. This study aimed to evaluate the effect of PEG 6000 on the growth of in vitro potato plantlets of the Dayang Sumbi cultivar and to determine the concentration that could still be tolerated under drought stress conditions. The experiment was conducted at the Botany Laboratory, Faculty of Mathematics and Natural Sciences, Universitas Lampung, using a Completely Randomized Design (CRD) with five PEG 6000 concentrations (0%, 5%, 10%, 15%, and 20%) and five replications. The observed parameters included plantlet survival percentage, plantlet height, number of leaves, and stomatal index. The data were analyzed using analysis of variance (ANOVA) followed by Tukey's Honestly Significant Difference (HSD) test at a 5% significance level. The results showed that all plantlets remained viable, with a 100% survival rate across all PEG 6000 concentrations during the two-week observation period. Significant differences were observed in plantlet height, leaf number, and stomatal index, all of which decreased progressively with increasing PEG 6000 concentration and reached their lowest values at 20% PEG 6000. A PEG 6000 concentration of 10% was found to support the growth tolerance of Solanum tuberosum L. cv. Dayang Sumbi plantlets under in vitro drought stress conditions.

Combined microbial inoculation improves plant growth, nutrient acquisition, and soil biological functioning in Opuntia ficus-indica under water deficit

Effect of plant growth promoting rhizobacteria on the growth promotion of Mustard CS61 (Brassica juncea)

Plant growth-promoting rhizobacteria consortia are used in the growth and augmentation of Mustard CS61 (Brassica juncea) under saline conditions to discover novel genes associated with stress tolerance and plant growth–promoting traits.