Salinity is considered the most limiting abiotic stress affecting both ecosystems and global agriculture by hampering plant growth and development, thus seriously limiting plant productivity and survival. Therefore, investigating the response to salt stress in plants is pivotal to understanding how ecosystems will face the effects of climate change. Salt stress is a very likely event in coastal ecosystems. The Mediterranean coastal ecosystems, such as salt marshes, host valuable plant species with heterogeneous degrees of tolerance to salt. La Albufera Natural Park in Valencia, Spain, is home to several species of Plantago known for their ability to withstand salt stress, such as P. coronopus and P. crassifolia, which are more tolerant than species like P. lanceolata or P. major. Moreover, some Plantago species are known to host diverse microbial endophyte species with potential beneficial effects.

The main objective of this research is to understand the molecular dynamics of salt stress gene expression when exposing Plantago species with different ecological strategies (glycophyte or halophyte) to 400 mM NaCl salt stress. Additionally, we will investigate the potential role of local soil microbiota on the plants’ response. RNA expression of salt-tolerant genes will be quantified at times 0, 2, 4, 8, 24 h, and when plants start to wilt. Morphological, physiological, and molecular stress markers will be recorded for each plant.

We found a heterogenous response of the biochemical markers of stress depending on the treatment or the Plantago species. Moreover, we found several fungal endophytes associated with the roots and leaves from wild P. crassifolia. We further discuss the different levels of gene expression.