Lu Lu, Xinying Chen, Pengkai Wang, Ye Lu, Jingbo Zhang, Xiuyan Yang, Tielong Cheng, Jisen Shi & Jinhui Chen

BMC Plant Biology; 21, Article number: 123 (2021); March 1 2021.

ABSTRACT

The CIPKs are a group of plant-specific Ser/Thr protein kinases acting in response to calcium signaling, which plays an important role in the physiological and developmental adaptation of plants to adverse environments. However, the functions of halophyte-derived CIPKs are still poorly understood, that limits a potential application of CIPKs from halophytes for improving the tolerance of glycophytes to abiotic stresses.

Results

In this study, we characterized the NtCIPK11 gene from the halophyte Nitraria tangutorum and subsequently analyzed its role in salt and drought stress tolerance, using Arabidopsis as a transgenic model system. NtCIPK11 expression was upregulated in N. tangutorum root, stem and blade tissues after salt or drought treatment. Overexpressing NtCIPK11 in Arabidopsis improved seed germination on medium containing different levels of NaCl. Moreover, the transgenic plants grew more vigorously under salt stress and developed longer roots under salt or drought conditions than the WT plants. Furthermore, NtCIPK11 overexpression altered the transcription of genes encoding key enzymes involved in proline metabolism in Arabidopsis exposed to salinity, however, which genes showed a relatively weak expression in the transgenic Arabidopsis undergoing mannitol treatment, a situation that mimics drought stress. Besides, the proline significantly accumulated in NtCIPK11-overexpressing plants compared with WT under NaCl treatment, but that was not observed in the transgenic plants under drought stress caused by mannitol application.

Conclusions

We conclude that NtCIPK11 promotes plant growth and mitigates damage associated with salt stress by regulating the expression of genes controlling proline accumulation. These results extend our understanding on the function of halophyte-derived CIPK genes and suggest that NtCIPK11 can serve as a candidate gene for improving the salt and drought tolerance of glycophytes through genetic engineering.

See: https://bmcplantbiol.biomedcentral.com/articles/10.1186/s12870-021-02878-x

Figure 1: N. tangutorum morphologically and biochemically responded to NaCl stress. a-h Morphology of N. tangutorum during salt treatment: 0 mM NaCl (Left) and 400 mM NaCl (right) treated plants for 0 day (a), 1 day (b), 2 days (c), 3 days (d), 4 days (e) and 8 days (f); the appearance of the plants after the 8-day treatment as described above and 1-day re-watering (g) and 10-day re-watering (h and h′) with tap water; red arrowheads indicate withering leaves; red stars indicate new leaves; scale bar: 1 cm. i-m Effect of NaCl stress on biochemical parameters: activities of POD (i), SOD (j), and CAT (k), proline content (l), and MDA content (m) in the N. tangutorum leaves. The data represent means ± SD of three biological replicates; statistical analyses were performed with one-way ANOVA test with LSD multiple comparisons, ‘*’ p < 0.05, ‘**’ p < 0.01, ‘***’ p < 0.001