Genome-Wide Identification Reveals That BZR1 Family Transcription Factors Involved in Hormones and Abiotic Stresses Response of Lotus (Nelumbo)

Abstract

The brassinazole-resistant (BZR) transcription factors (TFs) are key components of brassinosteroid (BR) signaling, which play an important role in regulating plant growth and development as well as responding to abiotic stress. However, a functional study of BZR transcription factors in lotuses has not been reported. A total 10 BZR1 genes (four NnBZR1 and six NlBZR1) were identified from the genomes of two lotus species (Nelumbo nucifera and Nelumbo lutea). The construction of the phylogenetic tree showed that the 10 BZR1 genes of the lotus were divided into four groups; the NnBZR1s and NlBZR1s were unevenly distributed on three and four chromosomes, respectively. Gene structure analysis showed that motif 1 and motif 9 are highly conserved in the lotus BZR1 protein, which might be related to the conserved domain BES_N of BZR1. The analysis of promoter cis-acting elements showed that the promoters of most of the BZR1 genes in the lotus contained elements related to light-responsive, ABA-responsive and abiotic stress-responsive factors, indicating that the BZR1 gene of the lotus played an important role in its response to abiotic stress. The responses of BZR1 genes to BR, ABA and four abiotic stresses (Cold, PEG6000, Cd and NaCl) were analyzed by qRT-PCR. The qRT-PCR results further verified that the lotus BZR1 genes play an important role in responding to hormone signals and resisting abiotic stress. This study laid the foundation for further research on the function of lotus BZR1 genes and provided a theoretical basis for future breeding and horticultural applications.