A regulatory network controlling developmental boundaries and meristem fates contributed to maize domestication

Area of Science:

• Genetics
• Plant Biology
• Agricultural Science

Background:

• Maize domestication involved selecting for traits like yield and architecture, but identifying genes controlling these traits is complex due to gene interactions.
• Previous research faced challenges in pinpointing causative genes because of epistasis and functional redundancy among domestication loci.

Purpose of the Study:

• To identify a key developmental regulator controlling both vegetative and reproductive traits in maize during domestication.
• To elucidate the molecular mechanism by which this regulator influences meristem fate and downstream domestication genes.

Main Methods:

• Utilized chromatin immunoprecipitation sequencing (ChIP-seq) to identify DNA-binding proteins.
• Integrated ChIP-seq data with genome-wide association analysis (GWAS) to pinpoint regulatory loci.
• Investigated gene function through analysis of gene interactions, including feedback loops and redundancy with homologs.

Main Results:

• Discovered a novel maize domestication gene, tasselsheath4 (tsh4), which acts upstream of multiple domestication loci.
• TSH4 establishes developmental boundaries and specifies meristem fates indirectly, without being expressed in the meristem itself.
• TSH4 employs a double-negative feedback loop involving microRNAs to regulate its own activity.
• TSH4 functions redundantly with homologs to positively regulate domestication loci, significantly contributing to doubled seed yield and ideal crop architecture.

Conclusions:

• Tasselsheath4 (tsh4) is a critical gene in maize domestication, playing a central role in yield enhancement and shaping plant architecture.
• The discovery of TSH4 provides insight into the genetic basis of crop improvement and the complex genetic architecture underlying domestication.