# A single-nucleotide mutation of G301A in GaIAA14 confers leaf curling in Gossypium arboreum

## TL;DR

A single mutation in the GaIAA14 gene causes leaf curling in Gossypium arboreum cotton, impacting leaf morphology and offering insights for crop improvement.

## Contribution

A single-nucleotide mutation in GaIAA14 is identified as the cause of leaf curling in Gossypium arboreum, revealing its role in auxin signaling.

## Key findings

- A G301A mutation in GaIAA14 leads to valine-to-isoleucine substitution, causing leaf curling in Gossypium arboreum.
- Silencing GaIAA14 in the mutant results in flattened leaves, confirming its role in leaf curling.
- Transcriptomic analysis shows altered expression of auxin-related genes due to the mutation.

## Abstract

Cotton is a crucial fiber and oil crop, playing a significant role in the textile and food industries. Its yield heavily relies on photosynthesis, a process that primarily occurs in the leaves. Consequently, leaf morphology stands as a vital agronomic trait in cotton breeding. However, research on the molecular mechanisms underlying cotton leaf morphogenesis remains relatively limited. Here we identified a curly leaf mutant (CU) in Gossypium arboreum by ethyl methylsulfonate (EMS) mutagenesis. The genetic analysis revealed that the curly leaf trait in this mutant is a semi-dominant characteristic controlled by a single gene. The map-based cloning of the CU locus showed a single-nucleotide mutation from G to A at the 301st positions in AUX/IAA14 protein (GaIAA14), which resulted in an amino acid substitution from valine (V) to isoleucine (I). After silencing GaIAA14 through virus-induced gene silencing (VIGS) technology in CU mutant, the leaves exhibited a flattened phenotype, indicating that GaIAA14 is a key gene regulating leaf curling in cotton. Comparative transcriptomic RNA-Seq analysis revealed significant changes in the expression levels of most auxin-related genes, suggesting that the mutation disrupts auxin signaling transduction. These findings establish a foundation for further functional studies of this gene and provide research strategies for leaf morphology improvement.