AUTHOR=Deng Huiwen , Wang Bin , Liu Yongxiang , Ma Li , Zong Yuanyuan , Prusky Dov , Bi Yang 

TITLE=Sodium Hydrosulfide Induces Resistance Against Penicillium expansum in Apples by Regulating Hydrogen Peroxide and Nitric Oxide Activation of Phenylpropanoid Metabolism

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.720372

DOI=10.3389/fmicb.2021.720372

ISSN=1664-302X

ABSTRACT=<p>As a multifunctional signaling molecule, hydrogen sulfide (H<sub>2</sub>S) has been reported to induce plant responses to a variety of abiotic stresses. However, there are no reports on H<sub>2</sub>S treatment inducing resistance in apples against <italic>Penicillium expansum</italic>, a biotic factor, and its possible mechanism of action. In this study, fumigating apples with 5 mM sodium hydrosulfide (NaHS), the exogenous donor of H<sub>2</sub>S, for 12 h reduced the diameter of lesions in fruit colonized by <italic>P. expansum</italic>. NaHS treatment markedly promoted the synthesis of endogenous H<sub>2</sub>S, hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), and nitrogen oxide (NO). <italic>In vivo</italic> NaHS treatment enhanced the activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, <italic>p</italic>-coumarate:coenzyme A ligase isoenzymes, caffeoyl-CoA-O-methyltransferase, caffeic acid-O-methyltransferase, ferulic acid-5-hydroxylase, cinnamyl-CoA reductase, and cinnamyl-alcohol dehydrogenase. The treatment also facilitated the production of specific phenolic acids, such as cinnamic acid, <italic>p</italic>-coumaric acid, caffeic acid, ferulic acid, and sinapic acid; total phenolic compounds; <italic>p-</italic>coumaryl alcohol; coniferyl alcohol; sinapyl alcohol; and lignin. NaHS treatment induced resistance against <italic>P. expansum</italic> in apples through H<sub>2</sub>O<sub>2</sub>- and NO-mediated activation of phenylpropanoid metabolism.</p>