Catechol O-methyltransferase homologs in Schizosaccharomyces pombe are response factors to alkaline and salt stress

Assessment of Yeasts as Potential Probiotics: A Review of Gastrointestinal Tract Conditions and Investigation Methods

Probiotics are microorganisms (including bacteria, yeasts and moulds) that confer various health benefits to the host, when consumed in sufficient amounts. Food products containing probiotics, called functional foods, have several health-promoting and therapeutic benefits. The significant role of yeasts in producing functional foods with promoted health benefits is well documented. Hence, there is considerable interest in isolating new yeasts as potential probiotics. Survival in the gastrointestinal tract (GIT), salt tolerance and adherence to epithelial cells are preconditions to classify such microorganisms as probiotics. Clear understanding of how yeasts can overcome GIT and salt stresses and the conditions that support yeasts to grow under such conditions is paramount for identifying, characterising and selecting probiotic yeast strains. This study elaborated the adaptations and mechanisms underlying the survival of probiotic yeasts under GIT and salt stresses. This study also discussed the capability of yeasts to adhere to epithelial cells (hydrophobicity and autoaggregation) and shed light on in vitro methods used to assess the probiotic characteristics of newly isolated yeasts.

Screening and identification of salt-tolerance genes in Sophora alopecuroides and functional verification of SaAQP

Overexpression of SaAQP can improve the salt tolerance of transgenic soybean hairy roots and A. thaliana. Salt stress severely affects crop yield and food security. There is a need to improve the salt tolerance of crops, but the discovery and utilization of salt-tolerance genes remains limited. Owing to its strong stress tolerance, Sophora alopecuroides is ideal for the identification of salt-tolerance genes. Therefore, we aimed to screen and identify the salt-tolerance genes in S. alopecuroides. With a yeast expression library of seedlings, salt-tolerant genes were screened using a salt-containing medium to simulate salt stress. By combining salt-treatment screening and transcriptome sequencing, 11 candidate genes related to salt tolerance were identified, including genes for peroxidase, inositol methyltransferase, aquaporin, cysteine synthase, pectinesterase, and WRKY. The expression dynamics of candidate genes were analyzed after salt treatment of S. alopecuroides, and salt tolerance was verified in yeast BY4743. The candidate genes participated in the salt-stress response in S. alopecuroides, and their overexpression significantly improved the salt tolerance of yeast. Salt tolerance mediated by SaAQP was further verified in soybean hairy roots and Arabidopsis thaliana, and it was found that SaAQP might enhance the salt tolerance of A. thaliana by participating in a reactive oxygen species scavenging mechanism. This result provides new genetic resources in plant breeding for salt resistance.