A Megabase-Scale Deletion Is Associated with Phenotypic Variation of Multiple Traits in Maize.

Genomic deletions are pervasive in the maize ( Zea mays L . ) genome and play important roles in phenotypic variation and adaptive evolution. However, little is known about the biological functions of these genomic deletions. Here, we reported the biological function of a megabase-scale deletion, which we identifed by position-based cloning of the multi-trait weakened ( muw ) mutant, which is inherited as a single recessive locus. MUW was mapped to a 5.16-Mb region on chromosome 2. The 5.16-Mb deletion in the muw mutant led to the loss of 48 genes and was responsible for a set of phenotypic abnormities, including wilting leaves, poor yield performance, reduced plant height, increased stomatal density, and rapid water loss. While muw appears to have resulted from double-stranded break repair that was not dependent on intragenomic DNA homology, extensive duplication of maize genes may have mitigated its effects and facilitated its survival.