Authors: Maryam Hadi; Anne Villacastin; Elizabeth Stacy
Affiliation: University of Nevada, Las Vegas
Keywords: Comparative genomics & genome evolution
The WRKY gene family is primarily a green lineage-specific group of genes that encode regulators involved in growth, development, and response to various biotic and abiotic stress. Variation in the structure and arrangement of WRKY genes has important implications for their roles in stress response and modulation in other gene regulatory networks. The WRKY gene family is well characterized in model species such as Arabidopsis thaliana and Oryza sativa, however, it has not yet been examined in an island adaptive radiation. Metrosideros (Myrtaceae) is the dominant woody genus in the Hawaiian Islands and a model island adaptive radiation. This monophyletic group comprises >20 taxa or morphotypes that are non-randomly distributed across the islands’ heterogeneous landscape and show heritable phenotypes and evidence of differential local adaptation. Recent studies have produced a high-quality chromosome-level reference genome assembly for Metrosideros polymorpha var. incana and shown divergent selection as a primary mechanism of diversification within the group. We posit that selection also drives variation in the structure and arrangement of WRKY genes across taxa. Using published reference genomes for M. polymorpha var. incana, M. polymorpha var. glaberrima, the Eucalyptus grandis (also Family Myrtaceae), and the model species, A. thaliana, we are performing a genome-wide search to identify, classify and determine the chromosomal localization of WRKY genes. Further, we will investigate the origin of gene duplication and loss, the mechanisms behind genomic rearrangements, type of selection, and homologous regions of the WRKY gene family across these genomes.
This study aims to find a relationship between the evolution of the WRKY gene family and differential local adaptation of taxa within an island adaptive radiation. This information will further our understanding of the molecular mechanisms underlying stress tolerance and adaptive divergence in trees.