Overexpression of BrCIPK1 Gene Enhances Abiotic Stress Tolerance by Increasing Proline Biosynthesis in Rice

Abstract

The calcineurin B-like protein (CBL)-CBLinteracting protein kinase (CIPK) pathway is emerging as a major signaling pathway in plants. To understand the function of CIPK, the gene named BrCIPK1 from Brassica rapa were introduced into rice. Characterization of BrCIPK1 gene showed a 1982 bp, containing 1509 bp coding region and 502 amino acids. Green fluorescent protein (GFP)-tagged BrCIPK1 was observed exclusively in the cytoplasmic and peripheral regions in the plant cell. Gene expression showed that its messenger RNA (mRNA) transcription in B. rapa was differentially accumulated in the presence of cold, salinity, and drought, indicating its biological roles in multiple stress response pathways in plants. Furthermore, Ubi-1::BrCIPK1 rice lines showed significantly higher biomass, water content, and proline and free sugar content relative to those in the wild-type Gopum. The BrCIPK1 interacted with rice calcineurin B-like protein 1 and 5 (OsCBL1, OsCBL5), suggesting that it is activated by Ca 2+ -bound CBLs in the cytosol by calcium spiking and regulates its downstream target proteins in these regions to increase abiotic stress tolerance. The results imply that BrCIPK1 gene may be involved in stress adaptations through the activation of pyrroline-5-carboxylate synthase in the proline biosynthetic pathway. In this paper, a hypothetical mechanism of elevated tolerance to cold, drought, and salinity is presented.

Transcriptome analysis of two contrasting rice cultivars during alkaline stress

“…Alkaline stress and salt stress are often interconnected and may induce mixed effects, such as osmotic, specific ion and high-pH effects, and therefore are difficult to control and engineer 34 – 36 . Studies have used stress-responsive genes to improve the resistance of rice to adverse environments by gene transformation 37 – 39 , and many genes are involved in the responses of rice to various abiotic stresses 40 – 43 . Studies in recent years have provided valuable information on the molecular mechanisms for stress resistance in plants based on morphological, physiological and molecular responses.…”

Effect of various drought stresses and subsequent recovery on proline, total soluble sugar and starch metabolisms in Rice (Oryza sativaL.) varieties

“…In rice, the concentration of proline was remarkable increased during drought stress (Mostajeran & Rahimi-Eichi, 2009). Abdula et al (2016) found that the increasing of proline biosynthesis enhanced abiotic stress tolerance in rice varieties. However, Bing-Sheng et al (2014) suggested that proline accumulation is not correlated with salt, alkaline and osmotic stresses in rice.…”

An apple sucrose transporter MdSUT2.2 is a phosphorylation target for protein kinase MdCIPK22 in response to drought

“…In maize, ZmCIPK8 is involved in plant responses to drought and other abiotic stresses by regulating stress-related genes (Tai et al, 2016). The expression of the P5CS1 gene is regulated by OsCIPK1, enhancing production of proline which acts as a cryoprotectant during cold stress and as osmolyte during drought stress in rice (Abdula et al, 2016). Both wheat TaCIPK2 and Stipa purpurea SpCIPK26 positively regulate the expression CAT genes, thereby negatively modulating H 2 O 2 content Zhou et al, 2016).…”