Functional characterization of AarMIXTAs as essential regulators in T-shaped non-glandular trichome development of Artemisia argyi.

Trichomes are crucial for plant defense and secondary metabolite biosynthesis. In Artemisia argyi, T-shaped non-glandular trichomes (TSTs) are a defining morphological feature and the primary structural component of moxa floss. We observed pronounced TST accumulation on the lower leaf surfaces. To elucidate the genetic regulation of TST development, we performed comparative transcriptomics of TSTs and non-TST tissues. This identified several MIXTA-like transcription factors (named AarMIXTAs) as key regulators of TST differentiation. Phylogenetic analyses revealed gene expansion and functional divergence between the AarMIXTAs and their homologs in Artemisia annua. Heterologous overexpression of AarMIXTA1.2 in Arabidopsis significantly increased TST density, demonstrating its positive regulatory role via transcriptional activation of downstream targets. These findings elucidate molecular mechanisms underlying TST morphogenesis and provide a genetic framework for enhancing moxa floss yield in A. argyi cultivars.