Construction of the KNOX-BELL interaction network and functional analysis of CmBLH2 under cold stress in Chrysanthemum morifolium.

The three-amino-acid-loop-extension (TALE) homeodomain transcription factor family, including the KNOX and BELL subfamilies, is one of the largest gene families in plants. This family encodes plant-specific transcription factors that play critical roles in regulating plant growth, development, and stress responses. However, their interaction network, as well as resistant functional mechanism in is rarely reported. In this study, 60 members of the TALE transcription factor family in chrysanthemum (Chrysanthemum morifolium) were systematically identified. These genes are distributed across 27 chromosomes, with most originating from whole-genome duplication events. Through comprehensive analyses of evolution, gene structure, and cis-regulatory elements, the expression patterns of these genes were elucidated, highlighting their roles in various developmental stages and stress responses, thereby expanding our understanding of the TALE gene family's functions in plants. Additionally, a KNOX-BELL protein interaction network in chrysanthemum was constructed, revealing 31 interaction pairs, including seven previously unreported combinations. The study also finds that the overexpression of CmBLH2 enhanced the activity of antioxidant system, reducing cellular damage under cold stress, while RNAi lines exhibited lower reactive oxygen species scavenging capacity. This research lays the foundation for further investigation of the TALE gene family's roles in development and stress responses in chrysanthemum and other species.