Daily humidity oscillation regulates the circadian clock to influence plant physiology

• Published in: Nature communications Vol. 9; no. 1; pp. 4290 - 10
• Main Authors: Mwimba, Musoki, Karapetyan, Sargis, Liu, Lijing, Marqués, Jorge, McGinnis, Erin M., Buchler, Nicolas E., Dong, Xinnian
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16-10-2018; Nature Publishing Group; Nature Portfolio
• Subjects: 38/5; 38/77; 38/88; 631/449/1659; 631/449/2169; Arabidopsis - microbiology; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Biological clocks; Circadian Clocks - physiology; Circadian rhythm; Circadian rhythms; DNA-Binding Proteins - genetics; Fitness; Gene Expression Regulation, Plant; Humanities and Social Sciences; Humidity; Immunity; Light effects; multidisciplinary; Mutation; Photoperiod; Physiology; Plant Immunity; Plant physiology; Plants, Genetically Modified; Repressor Proteins - genetics; Science; Science (multidisciplinary); Transcription Factors - genetics; Virulence
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-06692-2

Early circadian studies in plants by de Mairan and de Candolle alluded to a regulation of circadian clocks by humidity. However, this regulation has not been described in detail, nor has its influence on physiology been demonstrated. Here we report that, under constant light, circadian humidity oscillation can entrain the plant circadian clock to a period of 24 h probably through the induction of clock genes such as
CIRCADIAN CLOCK ASSOCIATED 1
. Under simulated natural light and humidity cycles, humidity oscillation increases the amplitude of the circadian clock and further improves plant fitness-related traits. In addition, humidity oscillation enhances effector-triggered immunity at night possibly to counter increased pathogen virulence under high humidity. These results indicate that the humidity oscillation regulates specific circadian outputs besides those co-regulated with the light-dark cycle.
Humidity has been shown to influence many aspects of plant physiology. Here Mwimba et al. show that oscillating humidity entrains the circadian clock under constant light conditions and enhances clock amplitude in simulated natural environments, while also improving immunity and overall growth.