Genome-wide analysis of LBD transcription factors reveals PvLBD12 expression profile involved in salt stress in switchgrass (Panicum virgatum L.)

Abstract Abiotic stresses seriously limit plant development and productivity and harm the agricultural economy. It is important, therefore, to understand the mechanism of salt tolerance in plants. Lateral organ boundaries domain (LBD) proteins are plant-specific transcription factors that have been reported to regulate plant lateral organ development, plant regeneration, and abiotic stress. In this study, we identify 69 LBD family members from switchgrass genome-wide sequences, and classify them according to their homology with LBD genes in Arabidopsis. Sixty-two cis-acting elements were identified from switchgrass LBD genes, and we found that most cis-acting elements can respond to light, control plant growth and development, regulate circadian rhythm, and respond to stress. Similarly, the results of qRT-PCR showed that PvLBD genes had different expression patterns under abiotic stress conditions, indicating that they may play important roles in stress response. In addition, candidate PvLBD target genes were enriched in many GO and KEGG pathways that play vital roles in the whole growth process and environmental stress response. PvLBD12 was selected as a candidate gene for functional analysis, and overexpression of PvLBD12 enhanced salt tolerance of transgenic switchgrass by altering a wide range of physiological responses. Overall, this study provides valuable information for better understanding the potential biological functions of LBD genes in plants.