Two SNP Mutations Turned off Seed Shattering in Rice.

Area of Science:

• Plant genetics
• Agronomy
• Evolutionary biology

Background:

• Seed shattering is a key trait influencing rice domestication and harvesting efficiency.
• Understanding the genetic basis of seed shattering is crucial for crop improvement.

Purpose of the Study:

• To investigate the genetic mechanism behind hybrid seed shattering in rice.
• To identify the gene responsible for this phenomenon and its role in domestication.

Main Methods:

• Utilized a near-isogenic line (NIL-hs1) derived from Oryza barthii.
• Genetic mapping to locate the causal gene on chromosome 4.
• Sequence analysis and comparative genomics of the HS1/SH4 gene.

Main Results:

• Identified the hybrid shattering 1 (HS1) gene, identical to SH4, as the cause of hybrid shattering.
• HS1 controls shattering through an ancestral haplotype with specific alleles (G at G237T, C at C760T).
• Homozygous domestic haplotypes confer non-shattering, while heterozygotes with the ancestral haplotype exhibit shattering.

Conclusions:

• The HS1 gene's ancestral haplotype drives hybrid shattering in rice.
• This finding elucidates the genetic nature of seed shattering during rice domestication.
• Results can aid in developing rice varieties with moderate shattering for mechanized harvesting.