A calmodulin-like protein from Kentucky bluegrass PpCML29 confers drought tolerance through activating antioxidant defense to maintain ROS homeostasis

Yihan Su; Yuhui Li; Weicong Luo; Ying Liu; Zhenfei Guo; Shaoyun Lu

doi:10.1016/j.jplph.2026.154708

A calmodulin-like protein from Kentucky bluegrass PpCML29 confers drought tolerance through activating antioxidant defense to maintain ROS homeostasis

J Plant Physiol. 2026 Jan 14:318:154708. doi: 10.1016/j.jplph.2026.154708. Online ahead of print.

Authors

Yihan Su¹, Yuhui Li², Weicong Luo³, Ying Liu⁴, Zhenfei Guo⁵, Shaoyun Lu⁶

Affiliations

¹ College of Life Sciences, Guangdong Engineering Research Center for Grassland Science, South China Agricultural University, Guangzhou, 510642, China. Electronic address: 20251190019@stu.scau.edu.cn.
² College of Life Sciences, Guangdong Engineering Research Center for Grassland Science, South China Agricultural University, Guangzhou, 510642, China. Electronic address: 15813383372@163.com.
³ College of Life Sciences, Guangdong Engineering Research Center for Grassland Science, South China Agricultural University, Guangzhou, 510642, China. Electronic address: 20223184046@stu.scau.edu.cn.
⁴ Key Laboratory of Superior Forage Germplasm in the Qinghai-Tibetan Plateau, Qinghai Academy of Animal and Veterinary Sciences, Qinghai University, Xining, 810016, China. Electronic address: liuying_yanhong@sina.com.
⁵ College of Grassland Science, Nanjing Agricultural University, Nanjing, 210095, China. Electronic address: zfguo@njau.edu.cn.
⁶ College of Life Sciences, Guangdong Engineering Research Center for Grassland Science, South China Agricultural University, Guangzhou, 510642, China. Electronic address: turflab@scau.edu.cn.

PMID: 41564472
DOI: 10.1016/j.jplph.2026.154708

Abstract

Calmodulin-like proteins (CMLs) are one of the Ca²⁺ sensors involving plant growth, development and adaptation to environmental stresses. The role of PpCML29 from a native Kentucky bluegrass (Poa pratensis L.) in regulating drought tolerance was investigated in the present study. PpCML29 is most similar to OsCML29 among all CML members in rice. PpCML29 protein locates in the cytoplasm and the nucleus. PpCML29 was expressed in roots, stems, leaves and spikes, with the highest level in leaves. PpCML29 expression was induced by 6-24 h of treatment with 23 % polyethylene glycol (PEG)-6000. Overexpression of PpCML29 led to increased drought tolerance, with higher levels of survival rate and relative water content (RWC) and lower levels of ion leakage in transgenic rice than in the wild type (WT) after drought and osmotic stress. In addition, lower water loss rate was observed in PpCML29-overexpressing lines compared with WT. Superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities and proline concentrations increased after osmotic stress, and higher levels were observed in PpCML29-overexpressing lines than in WT. Consistently, relative expressions of SOD1, SOD2, CAT1, CAT2, APX1, APX2, P5CS1 and P5CS2 as well as drought responsive marker genes including OsDREB1A, OsDREB2A, OsDREB2B, OsNCED3, OsLEA3 and OsRAB16A were induced by osmotic stress, with higher levels in PpCML29-overexpressing lines than in WT under osmotic stress. The results suggest that PpCML29 confers drought tolerance through upregulating drought responsive genes and activating proline biosynthesis and antioxidant defense system to maintain reactive oxygen species (ROS) homeostasis.

Keywords: Antioxidant defense; Calmodulin-like proteins; Drought responsive genes; Kentucky bluegrass; ROS homeostasis.