GWAS identifies candidate genes controlling adventitious rooting in Populus trichocarpa

Area of Science:

• Plant Biology
• Genetics
• Forestry

Background:

• Adventitious rooting (AR) is crucial for tree propagation, breeding, and genetic engineering.
• The genetic basis for AR heritability and polygenic nature is largely unknown.
• Understanding AR regulators is vital for improving tree traits.

Purpose of the Study:

• To identify genetic regulators of adventitious rooting (AR) in *Populus trichocarpa*.
• To overcome limitations in high-throughput phenotyping for AR traits.

Main Methods:

• Conducted a genome-wide association study (GWAS) on 1148 *Populus trichocarpa* genotypes.
• Developed a computer vision system for high-throughput measurement of AR traits (root length, area).
• Employed multiple GWAS methods to handle statistical challenges and enhance power.

Main Results:

• Identified 277 unique genetic associations related to AR.
• Discovered candidate genes involved in hormone signaling, cell division, ROS signaling, and other root development processes.
• Found numerous genes with previously uncharacterized or cryptic roles in AR.

Conclusions:

• The study reveals key genetic regulators underlying the complex polygenic control of AR in poplar.
• Identified candidate genes provide targets for future functional and physiological analyses.
• Advances understanding of AR for tree improvement and genetic applications.