Format: ORAL

Ian S. Gilman1,2 and Robert VanBuren1,2

1 Department of Horticulture, Michigan State University, East Lansing, MI, USA 2 Plant Resilience Institute, Michigan State University, East Lansing, MI, USA

The evolution of stress response mechanisms and their regulation have broad implications from the origins of evolutionary novelties to climate change adaptability across the tree of life. Crassulacean acid metabolism (CAM) is an adaptation to water and CO2 limitation that has evolved convergently in many dozens of plant lineages through the co-option of core carbon metabolic pathways. Despite the near-universal set of gene families exapted in each CAM origin, a diverse landscape of CAM phenotypes has evolved that vary along multiple axes, including the extent of nocturnal stomatal conductance, the amount of CO2 sequestered as malic acid, and the degree to which CAM is facultative or constitutive. The mounting genomic resources for CAM species across the vast number of convergent CAM origins makes CAM an ideal system for understanding the evolution of stress response gene regulation, and how such facultative responses can become constitutive. Here, we compare the regulatory elements of CAM gene networks from multiple independent origins of facultative and constitutive CAM plants to identify convergent patterns of regulatory evolution.