Genome‑wide identifcation and expression analysis of growth-regulating factors under drought in Brassica juncea

Growth-regulating factors (GRFs) are plant-specific transcription factors involved in the regulation of plant growth, development, and abiotic stress processes. However, the function of Brassica juncea (L.) Czern & Coss GRFs remain largely unknown. In this study, 34 BjGRF genes were identified in B. juncea. BjGRF members of the same subfamily were found to share a similar motif composition and gene structure. In total, 663 cis-acting elements were found in the promoter regions of BjGRF genes, which were related to light response, hormone response, environmental stresses, and plant growth/development. Additionally, 48 pairs of segmental duplication genes were identified during gene duplication events, and no tandemly duplicated genes were identified. qRT-PCR analysis showed that the 34 BjGRF genes were primarily expressed in the roots, followed by the leaves. Furthermore, the 10 BjGRF genes were screened in response to drought stress, and the expression patterns of the genes were relatively consistent, with a maximum expression level at 3 or 24 h, and the selected BjGRF03 and BjGRF32 might be involved in drought stress. This preliminary study clarifies the response of the BjGRF gene family to drought stress and provides ideas for further analyses of the biological functions of BjGRF genes.