Analysis of expression characteristics and identification of interaction proteins of transcription factor BnaABI5 in <i>Brassica napus</i>.

Rapeseed is one important oil crop in China. However, its planting benefit is frequently affected by environmental stresses such as drought in the northwest region of China. The abscisic acid(ABA) signaling pathway plays an important role in plant abiotic stress response and tolerance, and ABFs/AREBs(ABA-responsive element binding factors/ABA-responsive element binding proteins) are the core transcription factors that regulate the expression of ABA-responsive genes. To dissect the key transcription factors mediated abiotic stress, we mainly characterized abscisic acid insensitive 5(BnaABI5) in rapeseed, including its subcellular localization, expression pattern in response to various stress and tissue-specific expression analysis, transcriptional activity analysis as well as interaction screening with BnaMPKs(mitogen-activated protein kinases). Our results showed that the BnaABI5-GFP fusion protein was localized in the nucleus, and its transcript level is induced by drought stress and was mainly expressed in the roots of rapeseed. Furthermore, BnaABI5 showed transcriptional activation activity through a yeast transactivation assay and it also activated the promoter activity of <i>EM6</i> target gene in the transient expression system in tobacco leaves. Moreover, BnaABI5 interacted with BnaMPK6 and BnaMPK13 through BiFC and Y2H analysis. This study preliminarily explored the expression characteristics of transcription factor BnaABI5 and its interaction with BnaMPKs, which might help us for further understanding the function of BnaABI5.