Structure, evolution, phylogeny, and analysis of domain-deficient genes in the IQD gene family of Brassica juncea

The plant IQD gene family plays crucial roles in abiotic stress response and plant growth regulation. However, the biological functions of IQD genes in Brassica juncea remain largely unknown. Here, we conducted biological analyses to identify and characterize the IQD gene family in B. juncea, providing new insights for future research on the IQD gene family. We identified 107 IQD genes in B. juncea, which are distributed across 18 chromosomes. Collinearity analysis reveals that segmental duplication was the primary mode of replication for IQD genes during evolution. The Ka/Ks ratio indicates that the BjIQD genes underwent strong purifying selection during evolution. GO functional annotation analysis shows that protein binding, tubulin binding, and microtubule binding are the most enriched GO terms. qRT-PCR analysis reveals that the BjIQD genes are regulated in response to Zn stress. Furthermore, some genes lacking the key IQ and DUF4005 domains were analyzed, and we hypothesize that these domain-deficient genes may still perform certain biological functions. This study analyzed the B. juncea IQD gene family from multiple perspectives and explored members lacking key domains. These findings provide insights into the evolution of the BjIQD genes and the analysis of different gene families.