Application of Plant Growth-Promoting Bacteria from Cape Verde to Increase Maize Tolerance to Salinity

Abstract

Salinity constitutes a major abiotic factor that negatively affects crop productivity. Inoculation with plant growth-promoting bacteria (PGPB) is proven to increase plant tolerance to abiotic stresses and enhance plant growth, development and productivity. The present study aims to increase the resilience of crops to salinity using bacteria from the microbiome of plants growing in saline environments. For that, the halotolerance of bacteria present in the roots of natural plants growing on Sal Island, which is characterized by its arid environment and maritime influence, was determined, with some strains having extreme halotolerance. Their ability to produce plant growth-promoting traits was evaluated, with most strains increasing indole acetic acid (26–418%), siderophore (>300%) and alginate (2–66%) production and phosphate solubilization (13–100%) under salt stress. The strains evidencing the best performance were inoculated in maize (Zea mays L.) plants and their influence on plant growth and biochemical status was evaluated. Results evidenced bacterial ability to especially increase proline (55–191%), whose osmotic, antioxidant and protein-protecting properties reduced protein damage in salt-stressed maize plants, evidencing the potential of PGPB to reduce the impact of salinity on crops. Enhanced nutrition, phytohormone production and osmolyte synthesis along with antioxidant response all contribute to increasing plant tolerance to salt stress.

Parallel Evolution of Salinity Tolerance inArabidopsis thalianaAccessions from Cape Verde Islands

“…Only 1% of all plants can tolerate high salt concentrations, complicating cultivation in saline areas such as islands or coastal regions (Garcia-Caparros et al, 2023). The Cape Verde Islands are located 600 km from its closest mainland off the coast of Africa and have high salinity both in their soil and inland water sources (Zhao and Filker, 2018; Cruz et al, 2023). The Cvi-0 accession of the model plant Arabidopsis thaliana was collected in these islands in the 1990s and has been extensively studied because of its unique characteristics (Alonso-Blanco et al, 2003; Alonso-Blanco et al, 2005; Jakobson et al, 2016; Durand et al, 2021; Shahzad et al, 2024).…”