Abstract
Archaea as one of the three domains of life are prokaryotes that are similar to bacteria, yet have distinct properties that separate them from Bacteria and Eukaryota. Most archaea and bacteria cells are similar in shape and size, but there are exceptions like the Haloquadratum walsbyi, which has flat and square-shaped cells. Archaea are the predominant living organisms that thrive in extreme environments, such as hot springs and salt lakes. Being one of the major extremophiles, haloarchaea are salt-loving organisms that live in high-salinity environments where the salt concentration typically ranges from 3M to 5M, which is more than five times the salinity of seawater. Haloarchaea is known to be pleomorphic, meaning they can take on a wide range of cell morphologies. It was also recently discovered that some of the Haloarchaea species experience shape transition as they go through different growth phases. In this study, we aim to explore the morphology of haloarchaea and their shape transition by observing 100 haloarchaea species across multiple time points of their growth using a confocal microscope. Combining these data with the phylogeny of haloarchaea, we aim to understand the pattern of cell morphology among haloarchaea genera and how their evolutionary pathway shaped it.