Molecular characterization of the genome-wide BOR transporter gene family and genetic analysis of BnaC04.BOR1;1c in Brassica napus.

BACKGROUND

Boron (B) deficiency is an agricultural problem that causes significant losses of crop yield in many areas of the world. However, systematic analysis of BOR family genes for B transport in rapeseed is still lacking. We aimed to identify and characterize BOR transporters in Brassica napus and the potential role of these transporters in B homeostasis in response to B deficiency.

RESULTS

Here, we identified 20 BOR transporters from the Brassica napus genome, which were classified into six distinct groups that represent clear orthologous relationships to their family members in Arabidopsis. qRT-PCR revealed distinct expression profiles for BnBORs in different tissues and in response to external B levels. The B-efficient cultivar QY10 accumulated more B in shoots than the B-inefficient cultivar W10, and overexpression of BnaBOR1;1c could alleviate shoot B-deficiency symptoms in W10 by distributing more B from roots to shoots. Additionally, BnBOR1;1c expression was up-regulated by B deficiency, and the induction of BnBOR1;1c was more intense in QY10. Moreover, two conserved InDels were found in the promoter regions of BnBOR1;1c within different B-efficient genotypes.

CONCLUSIONS

Overall, the molecular characterization of the BnBOR genes of two B-efficient cultivars and their responses to B deficiency highlights the diversity of the family members in B. napus, and BnaC4.BOR1;1c has potential as a candidate gene for improving B nutrition.