Oxidative stress causes cellular damage and genomic instability through the accumulation of reactive oxygen species (ROS) in plants, resulting in reduced crop production. Chemical priming, which can enhance plant tolerance to environmental stress using functional chemical compounds, is expected to improve agricultural yield in various plants without genetic engineering. In the present study, we revealed that non-proteogenic amino acid N-acetylglutamic acid (NAG) can alleviate oxidative stress damage in Arabidopsis thaliana (Arabidopsis) and Oryza sativa (rice). Exogenous treatment with NAG prevented chlorophyll reduction induced by oxidative stress. The expression levels of ZAT10 and ZAT12, which are regarded as master transcriptional regulators in response to oxidative stress, increased following NAG treatment. Additionally, Arabidopsis plants treated with NAG showed enhanced levels of histone H4 acetylation at ZAT10 and ZAT12 with the induction of histone acetyltransferases HAC1 and HAC12. The results suggest that NAG could enhance tolerance to oxidative stress through epigenetic modifications and contribute to the improvement of crop production in a wide variety of plants under environmental stress.

Humulus lupulus (hop) is a necessary material for beer brewing. Improved breeding cultivars of hops with enhanced tolerance to environmental stresses, such as drought and heat stress, accompanying climate change have been developed. However, a propagation system, which is needed for the proliferation of new cultivars, is not currently available for hops. In this study, we found that treatment of stem explants with 0.01–0.05 ppm gibberellic acid (GA3) induced the development of axillary buds in the hop cultivar Kirin-2, resulting in the proliferation of shoot branching. Additionally, 0.01 ppm benzyl adenine (BA) enhanced the development of axillary buds formed in response to 0.05 ppm GA3 in various hop cultivars, particularly Nugget. The development of axillary buds was strongly repressed by the application of 0.05 ppm BA at a concentration equal to the 0.05 ppm GA3 concentration, which showed the possibility that a high concentration of cytokinin preferentially prevents the effect of GA3 on the development of axillary buds in hops. These results indicated that combined treatment of stem explants with GA3 and cytokinin at appropriate concentrations is effective for the propagation of proliferated hop cultivars through shoot branching.