Endophytic bacterial diversity of Avicennia marina helps to confer resistance against salinity stress in Solanum lycopersicum

Abstract

The current study aimed to explore the endophytic bacterial diversity of Avicennia marina and the potential roles of these endophytes in counteracting saline conditions in tomato plants. Molecular analysis revealed strains from Paenibacillus, Bacillus, Microbacterium, Citrobacter, Lysinibacillus, Halomonas, Virgibacillus, Exiguobacterium, and Vibrio. However, Bacillus pumilus AM11 and Exiguobacterium sp. AM25 showed significantly higher growth in saline media. In response to salinity stress, tomato plants treated with AM11 and AM25 showed significantly higher (∼15-23%) biomass, photosynthetic rate and pigment accumulation compared to controls. Salinity-exposed plants had significantly reduced growth and increased (three-fold) lipid peroxidation, whilst glutathione, catalase, and peroxidase activities were significantly reduced. In contrast, AM11, AM25, and methionine improved these physiochemical attributes. The study concludes that the application of bacterial endophytes from plants growing in saline conditions can offer other plants similar stress-resistance potential. Such halophytic bacterial strains can be used to improve plant growth in saline conditions. ARTICLE HISTORY

Culturable Bacterial Endophytes Associated With Shrubs Growing Along the Draw-Down Zone of Lake Bogoria, Kenya: Assessment of Antifungal Potential Against Fusarium solani and Induction of Bean Root Rot Protection

“…Identification of the isolates based on their 16S rRNA gene sequence revealed a bias in the isolation of the genus, Bacillus. The tendency to isolate the endophytic Bacillus species was previously noted from a variety of plants (Ali A. et al, 2017;Mohamad et al, 2020;Sendi et al, 2020). Isolation of endophytic bacteria from two mangrove systems in Brazil by Castro et al (2014) also resulted in Bacilli as the most isolated genera followed by Gamma Proteobacteria, coinciding with our results.…”

“…Inoculation of bacterial endophytes into crop plants confers similar benefits to the plants in ameliorating the stress conditions, thereby promoting growth and productivity. For example, inoculation of tomatoes with bacterial endophytes having indole acetic acid (IAA) and catalase production capabilities (Ali A. et al, 2017 ) from the mangrove, Avicennia marina resulted in reduced effects of salinity stress and increased biomass and chlorophyll content in Solanum lycopersicum . Bacterial endophytes from three different halophytes by Kearl et al ( 2019 ) were able to enhance both root and shoot growth of alfalfa in the presence of salt.…”

Setting a Plausible Route for Saline Soil-Based Crop Cultivations by Application of Beneficial Halophyte-Associated Bacteria: A Review

“…For instance, the introduction of HT-PGPB with antioxidative properties enhanced soybeans’ gene expression of APX, CAT, and SOD when exposed to saline stress [ 140 ]. HT-PGPB with antioxidative activities reported also includes increased catalase and glutathione activities by Bacillus cereus , Bacillus subtilis , and Pantoea ananatis obtained from roots of Rhizophora apiculata [ 141 ], and Bacillus pumilus with catalase, glutathione, and polyphenol oxidase activities isolated from Avicenna marina [ 118 ].…”

“…Generally, HT-PGPB-inoculated crops yield superior outcomes in terms of enhanced salinity tolerance. The inoculated glycophytes will have a better relative water content, higher or reduced proline accumulations (that varies among various researches due to the different nature of the HT-PGPB and the status of the inoculated plant), optimal K + /Na + ratio, higher chlorophyll pigments content, and lowered lipid peroxidation activities [ 118 , 141 , 153 , 154 ].…”

Alleviation of Salinity Stress in Peanut by Application of Endophytic Bacteria

“…Although breeding of tolerant crop varieties is an option, to date there has been limited success in developing such salt-tolerant crop plants (Schubert et al, 2009), necessitated alternate ameliorating or management strategies to achieve sustainable crop growth in soils affected by salinity. The modification in root growth, enhanced uptake of K + concomitantly with a reduction in Na + intake, and up or downregulation of other metabolic processes (Compant et al, 2005;Ryan et al, 2008;Khaliq et al, 2015;Ali et al, 2017;Li et al, 2019;Fan et al, 2020) are also responsible for imparting salinity tolerance. Application of epigallocatechin-3-gallate, salicylic acid, kinetin, silicon, aspirin, Ag-nanoparticals, and spermidine externally have also been found to alleviate abiotic stresses in many plants (Ahammed et al, 2018;Ahanger et al, 2018Ahanger et al, , 2020Hussain et al, 2018;Kaur et al, 2018;Zhang et al, 2018;Alam et al, 2019;Ahmad et al, 2019;Khan et al, 2020).…”