ABSTRACT
Salinity stress is one of the most important problems in crop productivity. Plant growth-promoting bacteria (PGPB) can also confer stress tolerance in plants under saline soil conditions. In a previous work, it was reported that bacteria strains isolated from hypersaline sites mitigated salt stress in chili pepper (Capsicum annuum var. Caballero) plants and promoted plant growth in some cases. The aim of this study was to evaluate the modulation of gene expression in C. annuum plants by bacteria strains isolated from saline environments. Two bacteria strains from high salinity ponds in Guerrero Negro, BCS, Mexico (Bacillus sp. strain 32 and Staphylococcus sp. strain 155) and Azospirillum brasilense Cd (DSM 1843) were used. Significant improvement in fresh weight yield (stem (28%), root (128.9%), and leaves (20%)) was observed in plants inoculated with Bacillus sp. strain 32. qPCR analysis showed that both strains modulated the expression of stress-responsive genes (MYB, ETR1, JAR1, WRKY, and LOX2) as well as heat shock factors and protein genes (CahsfA2, CahsfA3, CahsfB3a, CaDNaJ02, and CaDNaJ04). Finally, the expression levels of genes related to early salt stress and ISR showed differences in plants with dual treatment (bacteria-inoculated and salt-stressed) compared to plants with simple salinity stress. This work confirmed the differential modification of the transcriptional levels of genes observed in plants inoculated with bacteria under salinity stress.
ABSTRACT
Bivalve mollusks bioaccumulate toxins via ingestion of toxic dinoflagellates. In this study, Crassostrea gigas was used to investigate the effects related to Prorocentrum lima exposure. Oysters were fed with three diets Isochrysis galbana (2 × 10(6) cell mL(-1)) control treatment; algal mix of I. galbana (2 × 10(6)) and P. lima (3 × 10(3) cell mL(-1)); and P. lima alone (3 × 10(3) cell mL(-1)). Feeding behavior changes, histopathological alterations, and expression patterns changes of genes involved in cell cycle (p21, cafp55, p53), cytoskeleton (tub, act), and inflammatory process (casp1) were evaluated. Results indicated that the presence of diarrheic shellfish poisoning by P. lima cells decreased the clearance rate (p < 0.05), induced structural loss, significantly decreased tubule area of the digestive gland (p < 0.05), and up-regulated in expression all gene (p < 0.05), suggesting that toxic cells might trigger inflammatory tissue process, disturb cell cycle and cytoskeleton representing a risk to oysters integrity.
