Importance of crop phenological stages for the efficient use of PGPR inoculants

Abstract

During the last decades, the incorporation of beneficial microorganisms in agriculture crop management has become a common practice. Seed coating of these microorganisms still faces technical issues, which limit its implementation in conventional agriculture. An adaption to widely established agricultural practices, e.g. fertigation, could help to overcome these issues. Here, using Bacillus velezensis strain BBC047, we show the influence of the crop phenological stages on the efficiency and success of microbial inoculation under agricultural conditions. In the commercial nursery, strain BBC047 improved growth in a variety of horticulture crops like basil, cabbage, tomato and bell pepper, the latter with the strongest effects in strengthening and accelerating the seedling growth (root and aerial biomass). For a field trial under productive conditions, different application strategies were compared, using bell pepper (Capsicum annuum L.) as crop under fertigation: conventional management (T1), application to the seedling (only nursery, T2), only post-transplant application (field, T3) and a combination of both (T4). In T2 and T4, the post-transplantation survival rate (p < 0.05) improved and the productivity of the plants increased (> 100%). Applications of BBC047 post-transplantation (T3) caused a lower increase in productivity (25%). Fruits from all three application strategies contained significantly more Vitamin C. We conclude that in conventional agriculture, the applications of PGPR inoculants to early crop phenological stages like nurseries are a viable alternative for the efficient use of PGPR inoculants. In comparison, a late introduction of a PGPR reduces its beneficial effect on crop productivity. We highlight that an appropriate timing in the use of PGPR inoculants is crucial for product development and success in sustainable agriculture.

Bio-Inoculation of Tomato (Solanum lycopersicum L.) and Jalapeño Pepper (Capsicum annuum L.) with Enterobacter sp. DBA51 Increases Growth and Yields under Open-Field Conditions

“…Similarly, Enterobacter cloacae subsp. dissolvens promoted growth and increased yields of soybean and wheat under open-field conditions [17], whereas bell pepper plants that were inoculated with the PGPR Bacillus velezensis strain BBC047 improved growth at different phenological stages under greenhouse conditions [18]. Also, studies in bell and jalapeño pepper plants inoculated with Pseudomonas tolaasii and Bacillus pumilus PGPR strains showed growth promotion compared to uninoculated plants under climatic chamber conditions [19].…”

Harnessing the Power of PGPR: Unraveling the Molecular Interactions Between Beneficial Bacteria and Crop Roots

“…PGPR can be applied through various methods such as seed inoculation, soil application, and fertigation. These methods have been demonstrated to improve nutrient availability, enhance root growth, and increase crop yields (Lopes et al, 2021;Mohanty et al, 2021;Stoll et al, 2021). For instance, the use of Bacillus velezensis strain BBC047 in nurseries and post-transplantation stages has significantly improved the growth and productivity of horticultural crops like basil, cabbage, tomato, and bell pepper (Stoll et al, 2021).…”

“…These methods have been demonstrated to improve nutrient availability, enhance root growth, and increase crop yields (Lopes et al, 2021;Mohanty et al, 2021;Stoll et al, 2021). For instance, the use of Bacillus velezensis strain BBC047 in nurseries and post-transplantation stages has significantly improved the growth and productivity of horticultural crops like basil, cabbage, tomato, and bell pepper (Stoll et al, 2021). Additionally, the combination of biochar with PGPR inoculants has been shown to enhance soil fertility and crop yield, particularly in acidic sandy soils (Kari et al, 2021).…”

“…Innovative approaches like immobilizing PGPR on biochar surfaces have shown promise in enhancing the effectiveness of PGPR inoculants (Kari et al, 2021). Moreover, the timing of PGPR application is crucial, with early-stage applications in nurseries being more effective than late-stage applications (Stoll et al, 2021).…”

“…Additionally, the survival and persistence of PGPR in the soil environment are critical factors that influence their effectiveness (Kong and Liu, 2022). Technical issues related to the formulation and application methods, such as seed coating, also need to be addressed to ensure the successful integration of PGPR into conventional agricultural practices (Stoll et al, 2021).…”