The temporal expression pattern of MND1 and key regulators of floral transition in annual and perennial Pooideae species

Abstract

The molecular mechanisms underlying differences in annual and perennial life-history strategies are poorly understood. However, studies have shown that perennials often exhibit delayed flowering compared to related annuals. Flowering is enabled by the transition from vegetative juvenile to the vegetative adult stage (vegetative phase change), whereby plants become competent to initiate floral development (floral transition). In Brassicaceae, these phase transitions are regulated by temporal changes in the expression of miR156, miR172, and various SPLs. Recently, the newly characterized gene, MND1, was proposed as a floral promoter in Hordeum vulgare by modulating the transcript levels of miR156 and miR172. Here, I have investigated the temporal expression pattern of these genes to study the molecular differences in life-history strategies in the grass subfamily Pooideae. I found that MND1 is a possible candidate for explaining differences in developmental transitions in Brachypodium, while I did not find support for this in Hordeum. However, in most species, linear regression models supported that MND1 might act as a regulator within this flowering pathway.