Acta Agriculturae Zhejiangensis ›› 2025, Vol. 37 ›› Issue (6): 1193-1202.DOI: 10.3969/j.issn.1004-1524.20240691

• Crop Science • Previous Articles     Next Articles

Endophytic fungal GG22 protein improves growth of Carthamus tinctorius L. seedling under stress conditions

ZHOU Danning1,2(), XU Jiao1, BAI Jing3, LIU Xiangnan1, ZHU Yunhao1,2,*()   

  1. 1. School of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450046, China
    2. Respiratory Disease Diagnosis and Treatment and New Drug of Henan Collaborative Innovation Center, Zhengzhou 450046, China
    3. Nanyang Vocational College, Nanyang 474550, Henan, China
  • Received:2024-07-31 Online:2025-06-25 Published:2025-07-08

Abstract:

To investigate the effects of the protein from endophytic fungus Fusarium oxysporum GG22 in Rehmannia glutinosa(GG22 protein) on plant growth, different fractions of GG22 protein (designated as G20, G40, G60, and G80) were obtained using graded precipitation with ammonium sulphate. Safflower(Carthamus tinctorius L.) seedlings were treated with these GG22 protein fractions (G20, G40, G60 and G80) to preliminarily explore their impact on seedling growth under three stress conditions(high temperature, low temperature, and salinity). The relative expression levels of genes involved in plant immunity—ARD1 (activated disease resistance gene 1), EDS1 (enhanced disease susceptibility gene 1), PAD4 (plant antitoxin-deficient gene 4), NPR(non-expressors of pathogenesis related gene), and CDKs(cyclin-dependent kinase gene), under stress conditions were analyzed using quantitative real-time PCR (qRT-PCR). The results showed that the G60 and G80 groups significantly influenced safflower seedling growth under various stress conditions. Under high-temperature stress, the fresh weight of seedlings in the G80 group was 1.41 times that of the control group, while the G60 group was 1.39 times that of the control group. Under low-temperature stress (G80 group) and salt stress (G60 group), shoot length, fresh weight, and dry weight of seedlings significantly increased compared with the control. GG22 protein treatment alleviated stress-induced damage to seedling roots, with the G60 and G80 groups showing significant effects. Additionally, the expression of ARD1, EDS1, PAD4, NPR, and CDKs genes were upregulated to varying degrees in the G60 and G80 groups under all three stress conditions. Proteomic analysis identified three protein sequences with high similarity to known elicitor proteins—Aspf2, PEMG1 and PeaT1, which were selected as candidate elicitors for subsequent isolation, purification, and functional characterization. In conclusion, the protein from Fusarium oxysporum GG22 can improve safflower seedling growth under stress conditions and may contain elicitor proteins that activate plant immune responses, suggesting its potential as a plant immune elicitor.

Key words: endophytic fungi, Fusarium oxysporum, stress, activator protein, Carthamus tinctorius L.

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