PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS, vol.1, pp.1-10, 2022 (SCI-Expanded)
Mercury (Hg) toxicity is an increasing problem
worldwide, with a negative impact on the environment and
living organisms including both animals and plants. In this
study, we analyzed molecular and biochemical changes
related to Hg toxicity in wheat (Triticum aestivum L.)
seedlings. Seven-day-old seedlings were exposed to various concentrations (5, 10, and 20 lM) of HgCl2 for 24 and
48 h. Our results showed that HgCl2 treatments led to an
increase in the Hg content of wheat leaves in a time- and
concentration-dependent manner. Furthermore, significant
increases were observed in hydrogen peroxide, malondialdehyde, and proline contents in response to Hg toxicity.
While all HgCl2 treatments decreased the level of superoxide dismutase (SOD), the level of catalase (CAT) was
reduced only in seedlings exposed to 5 lM of HgCl2.
Mercury stress caused a decline in the expression of Cu/ZnSOD, Fe-SOD, TaWRKY19, and TaDREB1 genes at both
exposure times. On the other hand, 10 and 20 lM HgCl2
treatments caused significant induction (1.9 to 6.1-fold) in
the expression of the CAT gene in wheat leaves. The
mRNA level of the Mn-SOD and TaWRKY2 genes showed
different patterns depending on the concentration and
exposure period of HgCl2. In conclusion, the findings of
this work demonstrate that Hg toxicity causes oxidative
damage in wheat seedlings and changes the expression of
some genes encoding WRKY and DREB transcription
factor families, which have important functions in abiotic
stress response.