Novel Finding on How Melatonin and Nanoselenium Alleviate 2,4‑D Butylate Stress in Wheat Plants

Nanoselenium (nano-Se) or melatonin (MT) foliar spray
reduces pesticide
stress by stimulating plant secondary metabolism and antioxidant capacity.
However, the effects of nano-Se and MT biofortification on the interaction
between plant secondary metabolic pathways and rhizosphere microbes
in mitigating 2,4-D butyrate stress remain unknown. Compared
to nano-Se or MT treatment alone, nano-Se and MT combined application
increased the antioxidant enzyme activities and decreased the MDA
(25.0%) and H2O2 (39.3%) contents with 2,4-D
butylate exposure. Importantly, they enhance the soil enzymes (S-FDA
by 53.1%), allelochemicals (luteolin by 164.1% and tricin by 147.3%),
as well as plant secondary metabolites (JA by 63.3% and 193.3% in
leaves and roots) levels. It also improved the beneficial microbial
abundance of Comamonadaceae, Sphingomonadaceae, and Rhodobacteraceae in the rhizosphere soil.
In conclusion, nano-Se and MT alleviate 2,4-D butylate stress in wheat
plants by enabling the interaction between rhizosphere microorganisms,
allelopathic substances, and secondary metabolites.