Abstract Calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) play an important role in regulation on plant abiotic stress tolerance. It is unknown whether CBL-CIPK pathway regulates abiotic stress tolerance in bermudagrass. In the present study, CdtCBL4 and CdtCIPK5 from triploid bermudagrass were characterized. CdtCBL4 and CdtCIPK5 transcripts were induced by dehydration and salt. In addition, low temperature induced CdtCIPK5 transcript, but inhibited CdtCBL4 transcript; ABA induced CdtCIPK5 transcript, but had no influence on CdtCBL4 transcript. Yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assay demonstrated CdtCIPK5 interacted with CdtCBL4. Overexpression of CdtCIPK5 and CdtCBL4 improved salt tolerance in transgenic rice compared with wild type, based on measurements on relative water content (RWC), chlorophyll content and Fv/Fm. CdtCIPK5 and CdtCBL4 overexpressing transgenic lines had a lower Na+ accumulation and a higher K+/Na+ ratio under salt stress. The higher transcript levels of OsNHX3, OsHKT1;1, OsHKT1;4, OsHKT1;5 were observed in CdtCIPK5 overexpressing plants than in WT. It is suggested that CdtCBL4-CdtCIPK5 pathway confers salinity tolerance by upregulating OsNHX3, OsHKT1;1, OsHKT1;4, OsHKT1;5 expression for maintenance of Na+/K+ homeostasis during salt stress.

中文翻译：

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CBL4-CIPK5 通路通过调节离子稳态赋予盐而不是干旱和寒冷的耐受性

摘要 钙调神经磷酸酶 B 样蛋白 (CBL) 和 CBL 相互作用蛋白激酶 (CIPK) 在调节植物非生物胁迫耐受性中起重要作用。CBL-CIPK通路是否调节狗牙根非生物胁迫耐受性尚不清楚。在本研究中，表征了来自三倍体狗牙根的 CdtCBL4 和 CdtCIPK5。CdtCBL4 和 CdtCIPK5 转录物由脱水和盐诱导。此外，低温诱导CdtCIPK5转录，但抑制CdtCBL4转录；ABA 诱导 CdtCIPK5 转录，但对 CdtCBL4 转录没有影响。酵母双杂交和双分子荧光互补 (BiFC) 测定表明 CdtCIPK5 与 CdtCBL4 相互作用。基于相对含水量 (RWC) 的测量，与野生型相比，CdtCIPK5 和 CdtCBL4 的过表达提高了转基因水稻的耐盐性，叶绿素含量和 Fv/Fm。CdtCIPK5 和 CdtCBL4 过表达的转基因品系在盐胁迫下具有较低的 Na+ 积累和较高的 K+/Na+ 比率。在 CdtCIPK5 过表达植物中观察到的 OsNHX3、OsHKT1;1、OsHKT1;4、OsHKT1;5 的转录水平高于 WT。表明 CdtCBL4-CdtCIPK5 通路通过上调 OsNHX3、OsHKT1;1、OsHKT1;4、OsHKT1;5 的表达来维持盐胁迫期间的 Na+/K+ 稳态，从而赋予耐盐性。