Bacilli Rhizobacteria as Biostimulants of Growth and Production of Sesame Cultivars under Water Deficit

Abstract

A strategy using bacilli was adopted aiming to investigate the mitigation of the effects of water deficit in sesame. An experiment was carried out in a greenhouse with 2 sesame cultivars (BRS Seda and BRS Anahí) and 4 inoculants (pant001, ESA 13, ESA 402, and ESA 441). On the 30th day of the cycle, irrigation was suspended for eight days, and the plants were subjected to physiological analysis using an infrared gas analyzer (IRGA). On the 8th day of water suspension, leaves were collected for analysis: superoxide dismutase, catalase, ascorbate peroxidase, proline, nitrogen, chlorophyll, and carotenoids. At the end of the crop cycle, data on biomass and vegetative growth characteristics were collected. Data were submitted for variance analysis and comparison of means by the Tukey and Shapiro–Wilk tests. A positive effect of inoculants was observed for all characteristics evaluated, contributing to improvements in plant physiology, induction of biochemical responses, vegetative development, and productivity. ESA 13 established better interaction with the BRS Anahí cultivar and ESA 402 with BRS Seda, with an increase of 49% and 34%, respectively, for the mass of one thousand seeds. Thus, biological indicators are identified regarding the potential of inoculants for application in sesame cultivation.

Molecular and biochemical responses of sesame (Sesame indicum L.) to rhizobacteria inoculation under water deficit

“…(2014) , the chlorophyll content in leaves is directly related to the nitrogen concentration in the plant. Lima et al. (2023) obtained similar results regarding chlorophyll content with the use of Bacillus in sesame cultivation.…”

“…Oxidative stress can be detoxified by various antioxidants that alleviate oxidative damage and thus confer drought resistance. For example, the activation of the enzymes superoxide dismutase and catalase serves this function ( Santos et al., 2022 ; Lima et al., 2023 ).…”

“…Among various abiotic stresses, water deficit is one of the most detrimental and leads to significant reductions in crop yield ( Wang et al., 2019 ). To mitigate the negative effects of drought, plants exhibit several physiological mechanisms that stem from the induction of various genes ( Mehmood et al., 2022 ), antioxidant defense systems ( Santos et al., 2022 ), and the accumulation of osmoprotectants ( Lima et al., 2023 ), among other factors.…”

“…and Bradyrhizobium spp., can be used as a strategy to mitigate water stress ( Brito et al., 2019 ; Lastochkina et al., 2019 ). The interaction between plants and microorganisms can also enhance the plant’s tolerance to water deficit, as already assessed in crops such as maize ( Kavamura et al., 2013 ; Santos et al., 2020 ), sorghum ( Santana et al., 2020 ), wheat ( Gontia-Mishra et al., 2016 ), foxtail millet ( Niu et al., 2018 ), tomato ( Gowtham et al., 2020 ), and more recently in sesame ( Lima et al., 2023 ). Inoculation with these bacteria can result in physiological changes such as the regulation of the antioxidant system ( Barbosa et al., 2018 ; Andrade et al., 2021 ), stomatal closure regulation by altering abscisic acid levels ( Chieb and Gachomo, 2023 ), and production of osmoregulators like trehalose and proline ( Barbosa et al., 2018 ).…”

“…Inoculation with these bacteria can result in physiological changes such as the regulation of the antioxidant system ( Barbosa et al., 2018 ; Andrade et al., 2021 ), stomatal closure regulation by altering abscisic acid levels ( Chieb and Gachomo, 2023 ), and production of osmoregulators like trehalose and proline ( Barbosa et al., 2018 ). For sesame cultivation, a pioneering study demonstrating PGPB as tools to reduce the effects of water stress was recently published by our research group ( Lima et al., 2023 ). However, the mechanisms triggered by these bacteria in sesame remain unknown.…”