MOLECULAR MECHANISMS CONTROLLING EARLY DEVELOPMENT IN ARABIDOPSIS

VACS, PAULA; RASIA, RODOLFO; GONZALEZ SCHAIN, NAHUEL

Rosario

Congreso; XXXIV Reunión de la Sociedad Argentina de Fisiología Vegetal; 2023

Seedlings germinating under the soil surface have evolved to an exquisite developmental program termed skotomorphogenesis. In darkness, seedlings rapidly elongate the hypocotyl toward the surface in a desperate search of light, while protecting the apical meristem against mechanical damage by forming a hook between the hypocotyl and the two closed cotyledons. A proper skotomorphogenic growth must be achieved until seedlings reach the light to ensure survival as they depend on limited seed reserves.In our previous work, by studying mutants in the core components of miRNA microprocessor, we uncovered a microprocessor-independent function of HYPONASTIC LEAVES 1 (HYL1) as a repressor of hook development. Our findings have led to hypothesized a possible connection between HYL1 action in skotomorphogenesis and the well-established and crucial function of the phytohormones auxins in hook development. We discovered that HYL1 plays a crucial role in establishing the auxin gradient in apical hooks, however, the precise mechanism responsible for this process remains unknown.Polar auxin transport (PAT) is essential for generating hormone gradients in different plant tissues and mainly depends on the polarized localization of PIN auxin transporters in the plasma membrane. PAT is regulated by several mechanisms, and flavonoids such as quercetin and kaempferol have been proposed as possible PAT modulators. In this work, we study the localization of auxin transporter PIN3 in hooks of HYL1 mutants and also seek for possible alterations in the flavonoid pathway.