Detection of abscisic acid and relative transcript abundance in Syntrichia caninervis Mitt.

ABSTRACT Introduction. Abscisic acid (ABA) is a plant hormone known to regulate environmental stress responses in various species. Endogenous ABA has been detected in only a limited number of bryophyte species. Methods. Samples of the desiccation-tolerant moss Syntrichia caninervis Mitt. were analysed by ultra-performance liquid chromatography–mass spectrometry to determine the endogenous ABA content of the gametophores. Quantitative real-time PCR was conducted to investigate the transcript abundance of ABA-related genes (ZEP, NCED3, SnRK2, ABI1 and ABI5) during dehydration and rehydration and in response to exogenous ABA and cold stress. Key results. Over a 24 h period of dehydration, the mean ABA concentration of the gametophores ranged from 7.96 to 30.87 ng/g dry weight, being maximal at 6 h. The expression of ABA-related genes changed in response to abiotic stress. Conclusions. The results show that Syntrichia caninervis can generate ABA and suggest that ABA has crucial functions in the stress responses of this species. Our findings establish a foundation for further research on the physiological roles of ABA in S. caninervis and help extend our understanding of the biosynthetic, metabolic and signalling pathways of ABA in bryophytes.