Abstract
BackgroundChrysanthemum, a leading ornamental species, does not tolerate salinity stress, although some of its related species do. The current level of understanding regarding the mechanisms underlying salinity tolerance in this botanical group is still limited.ResultsA comparison of the physiological responses to salinity stress was made between Chrysanthemum morifolium ‘Jinba’ and its more tolerant relatives Crossostephium chinense, Artemisia japonica and Chrysanthemum crassum. The stress induced a higher accumulation of Na+ and more reduction of K+ in C. morifolium than in C. chinense, C. crassum and A. japonica, which also showed higher K+/Na+ ratio. Homologs of an Na+/H+ antiporter (SOS1) were isolated from each species. The gene carried by the tolerant plants were more strongly induced by salt stress than those carried by the non-tolerant ones. When expressed heterologously, they also conferred a greater degree of tolerance to a yeast mutant lacking Na+-pumping ATPase and plasma membrane Na+/H+ antiporter activity. The data suggested that the products of AjSOS1, CrcSOS1 and CcSOS1 functioned more effectively as Na+ excluders than those of CmSOS1. Over expression of four SOS1s improves the salinity tolerance of transgenic plants and the overexpressing plants of SOS1s from salt tolerant plants were more tolerant than that from salt sensitive plants. In addition, the importance of certain AjSOS1 residues for effective ion transport activity and salinity tolerance was established by site-directed mutagenesis and heterologous expression in yeast.ConclusionsAjSOS1, CrcSOS1 and CcSOS1 have potential as transgenes for enhancing salinity tolerance. Some of the mutations identified here may offer opportunities to better understand the mechanistic basis of salinity tolerance in the chrysanthemum complex.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0781-9) contains supplementary material, which is available to authorized users.
Highlights
Chrysanthemum, a leading ornamental species, does not tolerate salinity stress, some of its related species do
Variation for salinity tolerance in the chrysanthemum complex Most of the leaves of C. morifolium plants became wilted and chlorotic following a ten day exposure to the salinity stress, and their lower leaves were largely necrotic C. crassum plants were less severely affected by the treatment, while there was no evidence of any damage to either C. chinense or A. japonica plants, the leaves of which stayed green, with the plants maintaining a nearnormal level of growth for up to 14 days (Fig. 1)
The mean increase was notably lower for C. chinense and A. japonica: in these two species, the Na+ content in the roots rose by only 142.0 % and 156.0 % respectively, while for C. crassum and C. morifolium plants, the increase was 300.0 % and 324.0 % (Fig. 2a)
Summary
Chrysanthemum, a leading ornamental species, does not tolerate salinity stress, some of its related species do. The current level of understanding regarding the mechanisms underlying salinity tolerance in this botanical group is still limited. Soil salinity is becoming a severe environmental stress all over the world. Over 800 million hectares of the world’s arable land are adversely affected by salinity [1]. The major toxic cation present in saline soils is Na+, so under saline conditions, plants must minimize their cytosolic Na+ concentration to withstand the stress [2]. Under moderate salinity, sos mutant accumulated less Na+ in its shoots than WT (wild-type) plants, indicating that SOS1 participates in loading of Na+ into the xylem
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
