Application of the salt stress to the protoplast cultures of the carrot (Daucus carota L.) and evaluation of the response of regenerants to soil salinity

Agnieszka Kiełkowska,Katarzyna Maćkowska,Agnieszka Lis-Krzyścin,Ewa Grzebelus

doi:10.1007/s11240-019-01578-7

Agnieszka Kiełkowska, Katarzyna Maćkowska + Show 2 more

Open Access

https://doi.org/10.1007/s11240-019-01578-7

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Abstract

This is the first study to generate carrot plants for enhanced salinity tolerance using a single-cell in vitro system. Protoplasts of three carrot accessions were exposed to treatment by seven different concentrations of NaCl (10–400 mM). Salt concentrations higher than 50 mM decreased plating efficiency and those of 200–400 mM of NaCl completely arrested mitotic divisions of cultured cells. The protoplast-derived plants from the control and 50–100 mM NaCl treatment were subjected to an 8-week salt stress in greenhouse conditions induced by salinized soil (EC 3 and 6 mS cm−1). 50 mM NaCl stress applied in vitro induced polyploidy among regenerated plants. The regenerants obtained from the 50 and 100 mM NaCl-treated protoplast cultures grown in saline soil had a higher survival rate compared to the regenerants from the control cultures. The salt-stressed plants accumulated anthocyanins in petioles and produced denser hairs on leaves and petioles in comparison to the control plants. Salt stress influenced pollen viability and seed setting of obtained regenerants. The results suggest that salt stress applied in vitro in protoplast cultures creates variation which allows alleviating the negative effects of salt stress on the development and reproduction of the carrot.

Highlights

Salt-affected soils, are characterized by an excessive amount of soluble salts and having an effect on growing in it plants
10-day-old control cultures the number of cell colonies expressed by plating efficiency varied from 5.3% (NL) to 9.2% (Dolanka)
A significant decrease in plating efficiency in comparison to the control was observed on the media supplemented with NaCl at the concentration of 50 mM and higher; concentrations of 200 mM NaCl and higher completely arrested mitotic divisions as verified during three time-point observations of the culture (Table 2; Figs. 2g, 3)

Summary

Introduction

Salt-affected soils, are characterized by an excessive amount of soluble salts (i.e. chlorides and sulphates of sodium, calcium and magnesium) and having an effect on growing in it plants. The osmotic effects of salinity stress cause plasmolysis, inhibited cell expansion and cell death in roots, stems and young leaves, and stomatal closure (Flowers 2004; Kiełkowska 2017a, b). The plant’s response to both osmotic and ionic effects of salinity stress triggers enhanced demands on energy resources and energy metabolism; production of energy is usually severely reduced under salinity due to the reduction in photosynthetic rate, which can increase the production of reactive oxygen species (ROS) (Chen et al 2018). The salt tolerance mechanism in plants comprises sensing and signaling: transcriptomic response to stress, chromatin modifications, epigenetic and post-transcriptional regulation, transport and partitioning of Na+, and accumulation of osmolytes (Eryılmaz 2006; Deinlein et al 2014; Reguera et al 2014; Mansour and Ali 2017; Golkar and Taghizadeh 2018)

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