# Detailing Early Shoot Growth Arrest in Kro-0 x BG-5 Hybrids of Arabidopsis thaliana

## TL;DR

This study explores how hybrid Arabidopsis plants respond to cold temperatures by slowing shoot growth, revealing genetic and environmental factors involved.

## Contribution

The study identifies the Kro-0 allele of DRP3B as a key factor in shoot growth repression in Arabidopsis hybrids under cold conditions.

## Key findings

- The Kro-0 allele of DYNAMIN-RELATED PROTEIN 3B causes stunted shoot growth in the BG-5 background.
- Shoot growth repression in hybrids is most pronounced at the apex under low temperatures.
- Strigolactone hormones are associated with the dwarf phenotype in shoot growth repression.

## Abstract

Shoot growth directly impacts plant productivity. Plants adjust their shoot growth in response to varying environments to maximize resource capture and stress resilience. While several factors controlling shoot growth are known, the complexity of the regulation and the input of the environment are not fully understood. We have investigated shoot growth repression induced by low ambient temperatures in hybrids of Arabidopsis thaliana Kro-0 and BG-5 accessions. To continue our previous studies, we confirmed that the Kro-0 allele of DYNAMIN-RELATED PROTEIN 3B causes stunted shoot growth in the BG-5 background. We also found that shoot growth repression was most pronounced near the apex at a lower temperature and that the cells in the hybrid stem failed to elongate correctly. Furthermore, we observed that shoot growth repression in hybrids depended on light availability. Global gene expression analysis indicated the involvement of hormones, especially strigolactone, associated with the dwarf phenotype. Altogether, this study enhances our knowledge on the genetic, physiological and environmental factors associated with shoot growth regulation.