Functional Study of the Calmodulin-binding Protein StIQD20 in Mediating Salt Tolerance in Potato

doi:10.13560/j.cnki.biotech.bull.1985.2025-1346

Abstract

Abstract:

Objective This study aimed to elucidate the function of the potato StIQD20 gene in response to salt stress, clarify its intrinsic mechanism for enhancing potato salt tolerance, and provide new gene resources and genetic materials for molecular breeding of salt-tolerant potatoes. Method The StIQD20 gene was cloned, and an overexpression vector was constructed. The vector was transformed into the diploid wild-type potato ‘C65’ to obtain positive plants. Phenotypic traits and physiological and biochemical indicators of the overexpression plants and wild-type plants under different salt stress conditions were compared and analyzed. A Ca²⁺ phenotypic recovery experiment and expression level measurement of salt stress-related genes were conducted. Result Five overexpression plants were obtained. RT-qPCR analysis showed that the expression level of the StIQD20 gene in overexpression plants was 1.5-2.9 times higher than that in wild-type plants. Under salt stress, plant height, fresh weight, and number of blades of overexpression plants were higher than those of wild-type plants. The application of 100 μmol/L CaCl₂ was more effective than 50 μmol/L in alleviating seedling damage under salt stress conditions. Under different salt stress concentrations, the antioxidant enzyme activities and proline content in overexpression plants were significantly higher than those in wild-type plants, while malondialdehyde (MDA) content was significantly lower. The expression levels of salt stress-responsive genes SnRK2s, ABF4, ABI3, MYB2, and DREB2A in overexpression plants were higher than those in wild-type plants, while the expression level of the ABI5 gene was relatively lower. Conclusion StIQD20 significantly enhances salt tolerance in potato by modulating Ca²⁺ signaling and the antioxidant defense system, promoting the accumulation of osmoregulatory substances, and modulating the expression of related genes.

Key words: potato, StIQD20, callus transformation system, salt stress, Ca²⁺

FENG Rui-yun, LI Jing-hao, WANG Zi-teng, SONG Yu-peng, HOU Ya-jing, DUAN Yong-hong, SONG Qian-na, MEI Chao. Functional Study of the Calmodulin-binding Protein StIQD20 in Mediating Salt Tolerance in Potato[J]. Biotechnology Bulletin, 2026, 42(10): 207-215.

Figures/Tables 7

Fig. 1 Construction of the overexpression vector of StIQD20 in potato and analysis of gene expressionA: 1 represents the pMDC85 plasmid containing the target gene StIQD20; 2 represents the plasmid digested by Asc I-Pac I; M represents the 10 000 bp DNA marker. B: M represents the 2 000 bp DNA marker; N represents the negative control; P represents the positive control; 1-6 represent the positive colonies. C: M represents the 2 000 bp DNA marker; CW represents the wild type; P represents the recombinant vector plasmid; 8, 9, 13, 14, 18 represent the overexpressing positive plants. D: The recombinant vector map of pMDC85-StIQD20. E: C65 represent a diploid wild-type plant. OEs represent the overexpressing positive plants; significant differences among groups were identified using Duncan’s new multiple range test; values followed by different lowercase letters are significantly different (P<0.05); error bars in the figures denote average value ± the standard deviation derived from three independent biological replicates, n=3, the same below

Fig. 2 The genetic transformation process of positive plants overexpressing StIQD20 gene in potato

Fig. 3 Phenotypes between wild-type plants and overexpressing positive plants after 30 days of salt stress treatment

Fig. 4 Growth indicators of wild-type plants and overexpressing positive plants under salt stress

Fig. 5 Effects of different CaCl2 concentrations on the growth and development of potato seedlings under salt stress

Fig. 6 Changes in antioxidant indicators in plants under different NaCl concentrations

Fig. 7 Analysis of the expression levels of salt stress-related genes in StIQD20-overexpressing positive plants

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