RESUMEN
The bile acid sodium symporter (BASS) family plays an important role in transporting substances and coordinating plants' salt tolerance. However, the function of BASS in Brassica rapa has not yet been elucidated. In this study, eight BrBASS genes distributed on five chromosomes were identified that belonged to four subfamilies. Expression profile analysis showed that BrBASS7 was highly expressed in roots, whereas BrBASS4 was highly expressed in flowers. The promoter element analysis also identified several typical homeopathic elements involved in abiotic stress tolerance and stress-related hormonal responses. Notably, under salt stress, the expression of BrBASS2 was significantly upregulated; under osmotic stress, that of BrBASS4 increased and then decreased; and under cold stress, that of BrBASS7 generally declined. The protein-protein interaction analysis revealed that the BrBASS2 homologous gene AtBASS2 interacted with Nhd1 (N-mediated heading date-1) to alleviate salt stress in plants, while the BrBASS4 homologous gene AtBASS3 interacted with BLOS1 (biogenesis of lysosome-related organelles complex 1 subunit 1) via co-regulation with SNX1 (sorting nexin 1) to mitigate an unfavorable growing environment for roots. Further, Bra-miR396 (Bra-microRNA396) targeting BrBASS4 and BrBASS7 played a role in the plant response to osmotic and cold stress conditions, respectively. This research demonstrates that BrBASS2, BrBASS4, and BrBASS7 harbor great potential for regulating abiotic stresses. The findings will help advance the study of the functions of the BrBASS gene family.
RESUMEN
Nitrate transporter 2 (NRT2) proteins play vital roles in both nitrate (NO3-) uptake and translocation as well as abiotic stress responses in plants. However, little is known about the NRT2 gene family in Brassica rapa. In this study, 14 NRT2s were identified in the B. rapa genome. The BrNRT2 family members contain the PLN00028 and MATE_like superfamily domains. Cis-element analysis indicated that regulatory elements related to stress responses are abundant in the promoter sequences of BrNRT2 genes. BrNRT2.3 expression was increased after drought stress, and BrNRT2.1 and BrNRT2.8 expression were significantly upregulated after salt stress. Furthermore, protein interaction predictions suggested that homologs of BrNRT2.3, BrNRT2.1, and BrNRT2.8 in Arabidopsis thaliana may interact with the known stress-regulating proteins AtNRT1.1, AtNRT1.5, and AtNRT1.8. In conclusion, we suggest that BrNRT2.1, BrNRT2.3, and BrNRT2.8 have the greatest potential for inducing abiotic stress tolerance. Our findings will aid future studies of the biological functions of BrNRT2 family genes.