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

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.