Developmental mechanism of fusoid cells in the grass leaf and its response to light exposure

Abstract

Poaceae is a diverse, ecologically dominant family in which fusoid cells have been reported in seven of its 12 subfamilies: the early-diverging lineages Anomochlooideae, Pharoideae, Puelioideae; Oryzoideae, Bambusoideae and Pooideae; and Panicoideae. Anatomical studies have suggested that the development of fusoid cells is highly associated with shaded habitats. During leaf blade differentiation, fusoid cells increase in size and collapse at maturity, leading to speculation of a putative developmental programmed cell death (PCD) process. In contrast, the development of fusoid cells in leaf sheaths has never been satisfactory explained. This research plan aims to study the leaf sheath development with an emphasis on fusoid cells based on a phylogenetic framework. Ecological experiments will be carried out to test the influence of light exposure on the development of fusoid cells, as well as the occurrence of a PCD process. The results will be interpreted employing an ecological evolutionary developmental biology approach (eco-evo-devo), contributing towards growing knowledge on grass evolution and diversification.