SILENCING OF VLG, A DC1 PROTEIN, CAUSES FLAVONOID ACCUMULATION DURING SENESCENCE IN ARABIDOPSIS

ARIAS, L.; FRIK, J.; D IPPÓLITO, SEBASTIAN; CASALONGUE, C.; FONTANA, A; PICCOLI, P; FIOL, D

Salta

Congreso; SAIB PABMB 2019; 2019

SAIB

VLG (vacuoleless gametophytes) is a DC1 domain protein involved in vacuole formation during gametophytic development. DC1 domains are zinc fingers motives unique to plants that have been associated with several stress responses. In previous studies analyzing vlg promoter-GUS reporter lines subjected to different biotic and abiotic stress treatments, we showed that VLG is differentially regulated by numerous stress conditions in an organ specific manner. As vlg is a gametophytic mutation and homozygous mutants couldn?t be recovered, we generated a miRNA silenced lines to further study VLG function during stress. Although in normal growing conditions VLG silenced plants don?t seem to display abnormal phenotypes besides slight increase in leaf length, during senescence their leaves turn strong purple indicating accumulation of flavonoid compounds. Flavonoids are antioxidant compounds that prevent oxidative damage to some extent during senescence and other stress conditions. In order to investigate this, we quantified leaf pigments in a spectrophotometer, revealing that vlg silenced lines have less total chlorophyll content and more anthocyanin content compared to WT. Moreover, we further analyzed the metabolic profile of senescent leaf extracts through HPLC, particularly low molecular weight compounds and anthocyanins, and we show that vlg silenced plants display altered secondary metabolites composition compared to WT. In sum, results suggest that vlg silenced lines might suffer from higher oxidative stress during senescence, which causes chlorophyll degradation and flavonoid accumulation as a response. Funded by ANPCyT, Conicet, UNMdP, CIC.