AnDHN, a Dehydrin Protein From Ammopiptanthus nanus, Mitigates the Negative Effects of Drought Stress in Plants.

Yibo Sun,Muhammad Irfan,Linghao Liu,Lijing Chen,Shaokun Sun,Li Zhang,Wangzhen Han,Xiaojia Zhang

doi:10.3389/fpls.2021.788938

Yibo Sun, Muhammad Irfan + Show 6 more

Open Access

https://doi.org/10.3389/fpls.2021.788938

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Abstract

Dehydrins (DHNs) play crucial roles in a broad spectrum of abiotic stresses in model plants. However, the evolutionary role of DHNs has not been explored, and the function of DHN proteins is largely unknown in Ammopiptanthus nanus (A. nanus), an ancient and endangered legume species from the deserts of northwestern China. In this study, we isolated a drought-response gene (c195333_g1_i1) from a drought-induced RNA-seq library of A. nanus. Evolutionary bioinformatics showed that c195333_g1_i1 is an ortholog of Arabidopsis DHN, and we renamed it AnDHN. Moreover, DHN proteins may define a class of proteins that are evolutionarily conserved in all angiosperms that have experienced a contraction during the evolution of legumes. Arabidopsis plants overexpressing AnDHN exhibited morpho-physiological changes, such as an increased germination rate, higher relative water content (RWC), higher proline (PRO) content, increased peroxidase (POD) and catalase (CAT) activities, lower contents of malondialdehyde (MDA), H2O2 and O2–, and longer root length. Our results showed that the transgenic lines had improved drought resistance with deep root system architecture, excellent water retention, increased osmotic adjustment, and enhanced reactive oxygen species (ROS) scavenging. Furthermore, the transgenic lines also had enhanced salt and cold tolerance. Our findings demonstrate that AnDHN may be a good candidate gene for improving abiotic stress tolerance in crops.Key Message: Using transcriptome analysis in Ammopiptanthus nanus, we isolated a drought-responsive gene, AnDHN, that plays a key role in enhancing abiotic stress tolerance in plants, with strong functional diversification in legumes.

Highlights

For plant scientists, dramatically improving crop yields to meet the needs of an ever-increasing human population is an urgent matter at present and will become more pressing in the near future (Eshed and Lippman, 2019; Zhang et al, 2020a)
Our results show that AnDHN positively improves drought tolerance through morphological and physiological changes in A. nanus
Our data demonstrate that AnDHN is a membrane protein (Figure 3B), suggesting that AnDHN could be an upstream gene involved in drought tolerance

Summary

Introduction

Dramatically improving crop yields to meet the needs of an ever-increasing human population is an urgent matter at present and will become more pressing in the near future (Eshed and Lippman, 2019; Zhang et al, 2020a). Drought tolerance is the most critical strategy to prevent water loss and involves a series of physiological processes: (1) stomatal closure (reducing water loss), (2) increased root density and root length (increasing absorption of water), and (3) adjusting osmotic conditions at the cellular level by promoting the production of osmolytes, such as proline (PRO) and trehalose (Xie et al, 2006; Comas et al, 2013; Zhang et al, 2020b; Zhou et al, 2020) These key physiological responses and the expression of numerous downstream responsive genes under drought stress are mainly controlled by the hormone abscisic acid (ABA; Ullah et al, 2017; Gupta et al, 2020). The functions of proteins encoded by genes involved in drought resistance remain largely unknown in many diverse plant species

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