Silencing of VLG, a DC1 protein, causes flavonoid accumulation during senescence in Arabidopsis

DIPPÓLITO S; PICCOLI P; FRIK J; FONTANA A; ARIAS LA; CASALONGUE, CA; FIOL DF

Salta

Congreso; LV Annual SAIB Meeting and XIV PABMB Congress; 2019

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