Parallel domestication of the Shattering1 genes in cereals

Area of Science:

• Plant genetics
• Crop domestication
• Molecular evolution

Background:

• Seed shattering is a crucial trait lost during crop domestication.
• Understanding the genetic basis of this trait is key to crop improvement.

Purpose of the Study:

• To identify the gene controlling seed shattering in sorghum.
• To investigate the evolutionary origins of non-shattering mutations in sorghum, rice, and maize.

Main Methods:

• Gene identification and characterization in sorghum.
• Analysis of mutations in regulatory and coding regions of the Shattering1 (Sh1) gene.
• Comparative genomics and phylogenetic analysis of Sh1 orthologs in rice and maize.

Main Results:

• Sorghum seed shattering is controlled by the YABBY transcription factor gene, Shattering1 (Sh1).
• Domesticated sorghums possess three distinct non-shattering Sh1 mutations: promoter/intronic variants, a 2.2-kb deletion, and an exon-skipping splice-site variant.
• These mutations likely represent three independent domestication events.
• Orthologs in rice (OsSh1) and maize (ZmSh1) confirm the gene's role in shattering.

Conclusions:

• The Sh1 gene is a major target for seed shattering control in cereals.
• Parallel selection on Sh1 occurred during the domestication of sorghum, rice, and maize.
• These findings provide insights into the genetic mechanisms underlying crop domestication.