TASSELSHEATH4: A familiar player in maize development joins the domestication club

Abstract

The domestication of crops represents a cornerstone of human history, with one remarkable example being the evolution of maize (Zea mays) from its wild ancestor, teosinte. Researchers have identified several domestication genes in maize, such as TEOSINTE BRANCHED1 (TB1), GRASSY TILLERS1 (GT1), TASSELS REPLACE UPPER EARS1 (TRU1), and TEOSINTE GLUME ARCHITECTURE1 (TGA1), but little is known about higher-tier regulatory genes. Recent research by Dong and colleagues identified TASSELSHEATH4 (TSH4), a previously characterized gene that establishes developmental boundaries in maize, as a central player in maize domestication. Using recombinant inbred lines (RILs) and teosinte nested association mapping (TeoNAM) populations, the authors mapped TSH4 to a locus that controls key domestication traits. Functional analysis revealed that TSH4, along with its paralogs UNBRANCHED2 (UB2) and UB3, regulates the formation of vegetative and reproductive boundaries. Additionally, TSH4 targets known domestication genes, such as TB1, TRU1, and TGA1, demonstrating its central role in shaping the architecture of modern maize. This work identifies TSH4 as a key component of the domestication regulatory network and advances our understanding of the genetic mechanisms driving domestication and developmental boundary formation in plants.