Germination under stress conditions: the potential role of bbx24

CHIRIOTTO TS; BOTTO JAVIER

CABA

Congreso; Reunión conjunta de sociedades de biociencias; 2017

Reunión conjunta de sociedades de biociencias

The B-Box family of transcription factors consisted in 32 members (BBX1-BBX32) that play diverse functions in plant development. BBX transcription factors participate in germination, flowering, photomorphogenesis, shade avoidance syndrome, etc. Under stressconditions, BBX21 promotes the germination of Arabidopsis thaliana seeds through the abscisic acid (ABA) pathway inhibiting HY5 activity and preventing ABI5 expression (Xu et al., 2014). However, it is hardly known if other BBX proteins are involved in the regulation of germination under suboptimal conditions. The objective of this work is to investigate the role of BBX24 during germination under stress conditions. Wild-type (WT, Columbia), bbx24 null mutant and bbx24OX overexpressor seeds were sowed in agar medium with ABA, sodium chloride and polyethylene glycol. After chillling for three days, the boxes with seeds were exposed to white light/dark daily cycles of 12/12 h. Germination was recorded every 48 hours. Gene expression was evaluated using QRT-PCR technique in control and ABA-treated seeds exposed for 12 h in white light. However, both genotypes germinated at the same rates in water, bbx24 seeds germinated significantly lower than WT in ABA, sodium chloride and polyethylene glycol. We found a significant increase in the expression of genes related to ABA signaling pathway in bbx24 seeds with respect to WT. We conclude that BBX24 can promote germination under stress conditions through ABA signaling pathway.Keywords: B-box, germination, abscisic acid, stress conditions.