Pseudocrossidium replicatum (Taylor) R.H. Zander is a fully desiccation-tolerant moss that expresses an inducible molecular mechanism in response to severe abiotic stress

Selma Ríos-Meléndez,Claudio Delgadillo,Martha Bibbins-Martínez,Mario A Martínez-Núñez,Ignacio E Maldonado-Mendoza,Maria L Luna-Guevara,Emmanuel Valadez-Hernández,Mishael Sánchez-Pérez,Analilia Arroyo-Becerra,José L Martínez-Y-Pérez,Miguel Angel Villalobos-López,Luis Cárdenas

doi:10.1007/s11103-021-01167-3

Abstract

Key messageThe moss Pseudocrossidium replicatum is a desiccation-tolerant species that uses an inducible system to withstand severe abiotic stress in both protonemal and gametophore tissues.Desiccation tolerance (DT) is the ability of cells to recover from an air-dried state. Here, the moss Pseudocrossidium replicatum was identified as a fully desiccation-tolerant (FDT) species. Its gametophores rapidly lost more than 90% of their water content when exposed to a low-humidity atmosphere [23% relative humidity (RH)], but abscisic acid (ABA) pretreatment diminished the final water loss after equilibrium was reached. P. replicatum gametophores maintained good maximum photosystem II (PSII) efficiency (Fv/Fm) for up to two hours during slow dehydration; however, ABA pretreatment induced a faster decrease in the Fv/Fm. ABA also induced a faster recovery of the Fv/Fm after rehydration. Protein synthesis inhibitor treatment before dehydration hampered the recovery of the Fv/Fm when the gametophores were rehydrated after desiccation, suggesting the presence of an inducible protective mechanism that is activated in response to abiotic stress. This observation was also supported by accumulation of soluble sugars in gametophores exposed to ABA or NaCl. Exogenous ABA treatment delayed the germination of P. replicatum spores and induced morphological changes in protonemal cells that resembled brachycytes. Transcriptome analyses revealed the presence of an inducible molecular mechanism in P. replicatum protonemata that was activated in response to dehydration. This study is the first RNA-Seq study of the protonemal tissues of an FDT moss. Our results suggest that P. replicatum is an FDT moss equipped with an inducible molecular response that prepares this species for severe abiotic stress and that ABA plays an important role in this response.

Highlights

Due to climate change, rainfall frequency has decreased, and global temperatures have increased in recent years, resulting in an imbalanced ecosystem and hampering crop productivity (Fedoroff et al 2010)
We show that the moss P. replicatum is an fully desiccation-tolerant (FDT) species harbouring an inducible and rapid molecular mechanism that prepares it for desiccation
P. replicatum is a moss belonging to the Pottiaceae family that grows on soil or rocks of calcareous origin and has green stems ranging from 3 to 15 mm in height with a central strand (Fig. 1d)

Summary

Introduction

Rainfall frequency has decreased, and global temperatures have increased in recent years, resulting in an imbalanced ecosystem and hampering crop productivity (Fedoroff et al 2010). Effects of exogenous ABA on the dehydration and rehydration kinetics and Fv/Fm of P. replicatum gametophores In P. patens and other mosses, ABA induces an increase in tolerance to diverse abiotic factors (Werner et al 1991; Beckett et al 2000; Beckett 2001; Minami et al 2005; Nagao et al 2005; Frank et al 2005; Khandelwal et al 2010; Koster et al 2010; Komatsu et al 2013).

Results

Conclusion