Inoculation with rhizobacterial consortia alleviates combined water and phosphorus deficit stress in intercropped faba bean and wheat

Our study aimed to assess the role of inoculation of faba bean/wheat intercrops with selected rhizobacterial consortia (composed of one rhizobium and two P solubilizing bacteria “PSB”) to alleviate the effects of combined water deficit and P limitation on faba bean/wheat intercropping vs. monocropping under greenhouse conditions. One Vicia faba L (Aguadulce) and one Triticum durum L. variety (Karim) were grown as a sole crop or were intercropped in pots containing a sterilized substrate (sand:peat 4:1 v/v) with either rock phosphate (RP) (unavailable P) or KH2PO4 in the nutrient solution (available P). Plant inoculation was performed using the rhizobacterial consortia C1 (Rhizobium laguerreae, Kocuria sp., and Pseudomonas sp.) and C2 (R. laguerreae, Rahnella sp., and Kocuria sp.). Two weeks after inoculation, the plants were subjected to water deficit with 40% substrate water holding capacity (WHC) vs. 80% WHC for the well-watered plants. The trial was assessed at the flowering stage, and the results showed that inoculation with both consortia (C1 and C2) improved faba bean biomass in terms of shoot, root, and nodules dry weight compared to inoculation with rhizobia alone. C2 improved these parameters by 19.03, 78.99, and 72.73%, respectively. The relative leaf water content decreased under combined stress, especially in response to C1 conferring significant improvement of this parameter in wheat intercrops. In faba bean under P limitation, inoculation with C2 increased stomatal conductance (gs), phosphatase, and phytase activity by 35.73, 166.94, and 26.16%, respectively, compared to plants inoculated with rhizobia alone. Furthermore, C2 also improved membrane stability under P deficit by 44.33 vs. 16.16% for C1 as compared to inoculation with rhizobia alone. In sole-cropped faba bean, inoculation with both consortia improved N accumulation compared to single inoculation with an increase of 70.75% under P limitation. Moreover, under combined stress, inoculation with C2 improved biomass and N content (112.98%) in intercropped wheat compared to the sole crop. Our findings revealed that consortium C2 might offer an agronomic advantage under water and P deficit and could serve as a useful inoculum for enhancing faba bean and wheat production in monocropping and intercropping systems

Benefits of phosphate solubilizing bacteria on belowground crop performance for improved crop acquisition of phosphorus

Although research on plant growth promoting bacteria began in the 1950s, basic and applied research on bacteria improving use of phosphorus (P) continues to be a priority among many agricultural research institutions. Ultimately, identifying agriculturally beneficial microbes, notably P solubilizing bacteria (PSB), that enhance the efficient use of P supports more sustainable cropping systems and the judicious use of mineral nutrients. In parallel, there is more attention on improving crop root P acquisition of existing soil P pools as well as by increasing the proportion of fertilizer P that is taken up by crops. Today, new lines of research are emerging to investigate the co-optimization of PSB-fertilizer-crop root processes for improved P efficiency and agricultural performance. In this review, we compile and summarize available findings on the beneficial effects of PSB on crop production with a focus on crop P acquisition via root system responses at the structural, functional and transcriptional levels. We discuss the current state of knowledge on the mechanisms of PSB-mediated P availability, both soil- and root-associated, as well as crop uptake via P solubilization, mineralization and mobilization, mainly through the production of organic acids and P-hydrolyzing enzymes, and effects on phytohormone signaling for crop root developement. The systematic changes caused by PSB on crop roots are discussed and contextualized within promising functional trait-based frameworks. We also detail agronomic profitability of P (mineral and organic) and PSB co-application, in amended soils and inoculated crops, establishing the connection between the influence of PSB on agroecosystem production and the impact of P fertilization on microbial diversity and crop functional traits for P acquisition

Thymoquinone Alleviates Cadmium Induced Stress in Germinated Lens culinaris Seeds by Reducing Oxidative Stress and Increasing Antioxidative Activities

This study investigated the effect of thymoquinone on seeds germination and young seedlings of lentils under cadmium (Cd) stress (300 µM). Three different concentrations (10 µM, 1 µM, and 0.1 µM) of thymoquinone were applied. Our results indicated that thymoquinone has a positive effect on several physiological and biochemical parameters on seeds germination and young seedlings of lentils under Cd stress, which led to enhancing their growth. A significant increase in shoot and root length, fresh and dry weight, and chlorophyll content was observed in the treated plants compared to the control plants. However, the thymoquinone treatment significantly reduced malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents compared to untreated roots and seedlings under Cd-stress. Nevertheless, our results show that the thymoquinone significantly improved the activities of enzymes involved in antioxidant response, including superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), thioredoxin reductase (TrxR), and ascorbate peroxidase (APX). We have also studied the activities of isocitrate dehydrogenase (ICDH) and malate dehydrogenase (MDH); ICDH was increased significantly in roots and seedlings in the presence of different doses of thymoquinone. However, the activity MDH was increased only in roots. Our results suggest that the application of thymoquinone could mitigate cadmium induced oxidative stress

Data_Sheet_1_Inoculation with rhizobacterial consortia alleviates combined water and phosphorus deficit stress in intercropped faba bean and wheat.pdf

Our study aimed to assess the role of inoculation of faba bean/wheat intercrops with selected rhizobacterial consortia (composed of one rhizobium and two P solubilizing bacteria “PSB”) to alleviate the effects of combined water deficit and P limitation on faba bean/wheat intercropping vs. monocropping under greenhouse conditions. One Vicia faba L (Aguadulce) and one Triticum durum L. variety (Karim) were grown as a sole crop or were intercropped in pots containing a sterilized substrate (sand:peat 4:1 v/v) with either rock phosphate (RP) (unavailable P) or KH2PO4 in the nutrient solution (available P). Plant inoculation was performed using the rhizobacterial consortia C1 (Rhizobium laguerreae, Kocuria sp., and Pseudomonas sp.) and C2 (R. laguerreae, Rahnella sp., and Kocuria sp.). Two weeks after inoculation, the plants were subjected to water deficit with 40% substrate water holding capacity (WHC) vs. 80% WHC for the well-watered plants. The trial was assessed at the flowering stage, and the results showed that inoculation with both consortia (C1 and C2) improved faba bean biomass in terms of shoot, root, and nodules dry weight compared to inoculation with rhizobia alone. C2 improved these parameters by 19.03, 78.99, and 72.73%, respectively. The relative leaf water content decreased under combined stress, especially in response to C1 conferring significant improvement of this parameter in wheat intercrops. In faba bean under P limitation, inoculation with C2 increased stomatal conductance (gs), phosphatase, and phytase activity by 35.73, 166.94, and 26.16%, respectively, compared to plants inoculated with rhizobia alone. Furthermore, C2 also improved membrane stability under P deficit by 44.33 vs. 16.16% for C1 as compared to inoculation with rhizobia alone. In sole-cropped faba bean, inoculation with both consortia improved N accumulation compared to single inoculation with an increase of 70.75% under P limitation. Moreover, under combined stress, inoculation with C2 improved biomass and N content (112.98%) in intercropped wheat compared to the sole crop. Our findings revealed that consortium C2 might offer an agronomic advantage under water and P deficit and could serve as a useful inoculum for enhancing faba bean and wheat production in monocropping and intercropping systems.</p