Lee, Madeline2026-04-242026-04-242026-03-252026-03-252026-04-242026-04-24http://hdl.handle.net/1993/39766Climate change is increasing the frequency of flooding worldwide, which can damage crop plants by inhibiting gas exchange in below ground tissue. Low oxygen stress (hypoxia) in root tissue causes an increase in the levels of nitric oxide (NO) which interferes with epigenetic regulation through S-nitrosylation and inactivation of histone deacetylases such as HDA6. It is hypothesized that hypoxic stress could lead to an increase in both H3K9ac and H3K14ac because of elevated HDA6 S-nitrosylation by NO. To test this hypothesis the acetylation levels of lysine 9 and 14 of histone H3 (H3K9 and H3K14) were measured in root tips of WT plants and plants dysregulating the NO scavenger PHYTOGLOBIN 1. Low oxygen stress enhanced global acetylation levels H3K9 and H3K14. This effect was attenuated when PGB1 was constitutively expressed and exacerbated when PGB1 level was reduced. The Pgb1 modulation of H3K9ac and H3K14ac levels under hypoxia was consistent with NO being an epigenetic modifier in Arabidopsis root tips. The potential inhibition of HDA6 S-nitrosylation and mitigation of enhanced global levels of H3K9ac and H3K14ac by Pgb1 can protect the epigenome during hypoxic stress. Further understanding of the relationship between Pgb1 and the epigenome is important for elucidating how stress responses can be modified or accommodated to improve survival under waterlogging.engEpigeneticsArabidopsisHypoxiaHistone Acetylation