Identification of the Maize PP2C Gene Family and Functional Studies on the Role of ZmPP2C15 in Drought Tolerance
Author:
Pang Yunyun12, Cao Liru13, Ye Feiyu13, Ma Chenchen13, Liang Xiaohan13, Song Yinghui1, Lu Xiaomin13
Affiliation:
1. Grain Crops Research Institute, Henan Academy of Agricultural Sciences, Postgraduate T&R Base of Zhengzhou University, Zhengzhou 450002, China 2. School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450002, China 3. The Shennong Laboratory, Zhengzhou 450002, China
Abstract
The protein phosphatase PP2C plays an important role in plant responses to stress. Therefore, the identification of maize PP2C genes that respond to drought stress is particularly important for the improvement and creation of new drought-resistant assortments of maize. In this study, we identified 102 ZmPP2C genes in maize at the genome-wide level. We analyzed the physicochemical properties of 102 ZmPP2Cs and constructed a phylogenetic tree with Arabidopsis. By analyzing the gene structure, conserved protein motifs, and synteny, the ZmPP2Cs were found to be strongly conserved during evolution. Sixteen core genes involved in drought stress and rewatering were screened using gene co-expression network mapping and expression profiling. The qRT-PCR results showed 16 genes were induced by abscisic acid (ABA), drought, and NaCl treatments. Notably, ZmPP2C15 exhibited a substantial expression difference. Through genetic transformation, we overexpressed ZmPP2C15 and generated the CRISPR/Cas9 knockout maize mutant zmpp2c15. Overexpressing ZmPP2C15 in Arabidopsis under drought stress enhanced growth and survival compared with WT plants. The leaves exhibited heightened superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) activities, elevated proline (Pro) content, and reduced malondialdehyde (MDA) content. Conversely, zmpp2c15 mutant plants displayed severe leaf dryness, curling, and wilting under drought stress. Their leaf activities of SOD, POD, APX, and CAT were lower than those in B104, while MDA was higher. This suggests that ZmPP2C15 positively regulates drought tolerance in maize by affecting the antioxidant enzyme activity and osmoregulatory substance content. Subcellular localization revealed that ZmPP2C15 was localized in the nucleus and cytoplasm. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) experiments demonstrated ZmPP2C15’s interaction with ZmWIN1, ZmADT2, ZmsodC, Zmcab, and ZmLHC2. These findings establish a foundation for understanding maize PP2C gene functions, offering genetic resources and insights for molecular design breeding for drought tolerance.
Funder
Outstanding Youth Technology Fund of the Henan Academy of Agricultural Sciences National Natural Science Foundation of China Key Research Project of the Shennong Laboratory Major Science and Technology Projects in Henan Province
Subject
Plant Science,Ecology,Ecology, Evolution, Behavior and Systematics
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