TB1like

TB1like refers to a group of genes homologous to TEOSINTE BRANCHED1 (TB1), the classic plant regulator of shoot architecture. In plants, TB1like genes are typically members of the TCP transcription factor family, and they are found across many angiosperm species. They encode transcription factors that influence the development and activity of axillary buds, shoot branching, and inflorescence architecture, contributing to overall plant form and resource allocation.

The TB1like gene family is characterized by the conserved TCP domain, a basic-helix-loop-helix DNA-binding motif critical for protein–DNA interactions. The N- and C-terminal regions of TB1like proteins are more variable, which underpins functional diversification among species. In many plants, TB1like genes are classified as class II TCPs and are expressed in shoot apical meristems, axillary buds, and developing inflorescences, where they modulate growth in response to internal signals and environmental cues.

Functional roles attributed to TB1like genes include suppression or modulation of axillary bud outgrowth, leading to reduced branching or altered plant stature. Notable examples include OsTB1 in rice, which reduces tillering and shapes panicle architecture, and BRANCHED1 (BRC1) in Arabidopsis, a TB1like regulator of bud outgrowth. In tomato and other crops, TB1like activity similarly affects branching patterns and plant habit, with implications for yield and breeding.

TB1like regulation involves hormonal and signaling networks, including interactions with auxin transport, strigolactones, cytokinins, and environmental signals such as light and nutrient status. Comparative studies of TB1like genes provide insights into domestication, evolutionary conservation, and the genetic basis of plant architecture, informing crop improvement and breeding strategies.