MCTP controls nucleocytoplasmic partitioning of AUXIN RESPONSE FACTORs during lateral root development

The role of multiple C2 domain and transmembrane region proteins in mediating tomato development

Multiple C2 domain and transmembrane region proteins (MCTPs) are an evolutionarily conserved family involved in protein trafficking and signal transduction. Although several investigations have demonstrated that MCTPs play crucial roles in plant growth and development, their specific biological functions within tomatoes (Solanum lycopersicum L.) remain predominantly mysterious. In this study, we identify and characterize 14 SlMCTP genes derived from tomatoes. Chromosome mapping, gene structure, phylogenetic connections, and subcellular localization are presented herein. Meanwhile, the varied expression patterns of SlMCTPs within different tissues and under diverse hormonal and NaCl treatment conditions are revealed. Moreover, we find that SlMCTP10, SlMCTP11, and SlMCTP12, which belong to the same clade, display high expression levels at the main stem apex, suggesting their potential functions in shoot development. Furthermore, we knock out the SlMCTP10 gene in tomato using CRISPR-Cas9. The Slmctp10 seedlings exhibit defects in shoot meristem development, manifested by abnormal cotyledons and shorter internodes. Together, our findings offer fundamental insights into the SlMCTP family and uncover the role of SlMCTP proteins in regulating shoot meristem development in tomato plants.

Mechanisms of auxin action in plant growth and development

The phytohormone auxin is a major signal coordinating growth and development in plants. The variety of its effects arises from its ability to form local auxin maxima and gradients within tissues, generated through directional cell-to-cell transport and elaborate metabolic control. These auxin distribution patterns instruct cells in a context-dependent manner to undergo predefined developmental transitions. In this Review, we discuss advances in auxin action at the level of homeostasis and signalling. We highlight key insights into the structural basis of PIN-mediated intercellular auxin transport and explore two novel non-transcriptional auxin signalling mechanisms: one involving intracellular Ca2+ transients and another involving cell-surface auxin perception that mediates global, ultrafast phosphorylation. Furthermore, we examine emerging evidence indicating the involvement of cyclic adenosine monophosphate as a second messenger in the transcriptional auxin response. Together, these recent developments in auxin research have profoundly deepened our understanding of the complex and diverse activities of auxin in plant growth and development.

Genome-Wide Identification and Phylogenetic Characterization of the FTIP Gene Family in Maize (Zea mays)

The maize FT-interacting protein (FTIP) gene family represents a group of multiple C2 domain and transmembrane proteins (MCTPs), characterized by their unique structural motifs and membrane-spanning regions., plays crucial roles in intercellular communication and stress responses. Here, we systematically characterized 27 ZmFTIP genes unevenly distributed across 10 maize chromosomes. Phylogenetic analysis with rice, soybean, and Arabidopsis homologs revealed five evolutionary clades with monocot-specific conservation patterns. Promoter cis-element profiling identified hormone-responsive (ABA, JA, auxin) and stress-related motifs, corroborated by differential expression under abiotic stresses and phytohormone treatments. Notably, ZmFTIP18 and ZmFTIP25 showed sustained upregulation under cadmium exposure, while ZmFTIP13 exhibited downregulation. Synteny analysis demonstrated strong conservation with monocot FTIPs, suggesting ancient evolutionary origins. This comprehensive study provides foundational insights into ZmFTIP functional diversification and potential biotechnological applications.

Endoplasmic reticulum-anchored proteins in control of AUXIN RESPONSE FACTOR condensation

Sequestration of AUXIN RESPONSE FACTOR (ARF) transcription factors in cytoplasmic condensates represents a specialized mechanism for modulating cellular auxin responsiveness. In this issue of Developmental Cell, Xuan et al. show that MULTIPLE C2-DOMAIN AND TRANSMEMBRANE REGION PROTEIN (MCTP) proteins stimulate lateral root development by antagonizing ARF7 and ARF19 condensation.