Enhancing wheat resilience to salinity: the role of endophytic Penicillium chrysogenum as a biological agent for improved crop performance

Abstract

Salinity stress severely impacts wheat productivity, necessitating effective strategies to enhance crop resilience. This study investigates the potential of Penicillium chrysogenum CM022 as a biological agent to alleviate the impact of salinity stress on wheat (Triticum aestivum L.). P. chrysogenum CM022 improved germination of wheat seeds, particularly under salinity of 150 mM NaCl. Fungal inoculation significantly improved plant growth in terms of root length, plant height, and seedling biomass, even under high salinity conditions. Notably, inoculated plants preserved photosynthetic pigments and reduced oxidative damage, evidenced by lower levels of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), compared to non-inoculated controls. The inoculated plants also exhibited enhanced proline and soluble sugar contents, which are crucial for osmotic adjustment under stress. Additionally, P. chrysogenum CM022 significantly increased the antioxidant capacity of wheat, boosting total phenolic and flavonoid contents, and enhancing antioxidant enzyme activity under high salinity. These findings underscore the potential of P. chrysogenum CM022 in improving wheat tolerance to salinity stress through physiological, biochemical, and antioxidant defense mechanisms, supporting its use in sustainable agricultural practices to mitigate the adverse effects of salinity on crop production.

Keywords: Penicillium chrysogenum; Antioxidant enzymes; Endophytic fungi; Salinity resilience; Seed germination.

Fig. 1

Salinity tolerance of Penicillium chrysogenum CM022 across 0, 40, 60, 80 and 100 mM NaCl in PDA medium. Each column represents the mean of three replicates ± SD. Similar letters indicate non-significant differences at P˂0.05

Fig. 2

Effect of Penicillium chrysogenum CM022 inoculation on response of wheat germination to salinity of 0, 50, 100, and 150 mM NaCl in terms of (a) final germination percentage (b) mean germination time (c) mean germination rate. Each column represents the mean of three replicates ± SD. Means with the same letter are not significantly different at P˂0.05

Fig. 3

Effect of P. chrysogenum CM022 inoculation on salinity tolerance indices of wheat seedlings: (a) stem length tolerance index, (b) root length tolerance index, (c) fresh weight stress tolerance index, (d) dry weight stress tolerance index and (e) germination tolerance index

Fig. 4

(a) PCA of growth and germination traits of wheat, (b) Relationship analysis of wheat growth and germination traits under control and stress conditions, (c) Heatmap of Pearson correlation coefficients. Clustering distance is shown on the y-axis, with red and blue indicating positive and negative correlations, respectively. R: mean germination rate, GVI: germination vigor index, MGT: mean germination time, GP: germination percentage, SL: stem length, RL: root length, FW: fresh weight, DW: dry weight

Fig. 5

Effect of wheat inoculation with P. chrysogenum CM022 on plant performance under the impact of salinity stress. (a) hydrogen peroxide, (b) malondialdehyde, (c) proline and (d) soluble sugars. Each column represents the mean of 3 replicates ± SD. Similar letters indicate non-significant differences at P˂0.05

Fig. 6

Effect of P. chrysogenum CM022 inoculation on wheat non-enzymatic antioxidant activity under the impact of salinity stress. (a) phenolics, (b) flavonoids, (c) anthocyanin and (d) antioxidant activity. Each column represents the mean of 3 replicates ± SD. Similar letters indicate non-significant differences at P˂0.05

Fig. 7

Effect of P. chrysogenum CM022 inoculation on the activity of (a) catalase, (b) peroxidase, (c) polyphenol oxidase, and (d) ascorbate peroxidase in wheat leaves under the impact of salinity stress. Each column represents the mean of 3 replicates ± SD. Similar letters indicate non-significant differences at P˂0.05

Fig. 8

(a) PCA of growth, physiological and biochemical traits of wheat, (b) Analysis of wheat growth and performance in relation to endophyte inoculation across stress levels, (c) Heatmap of Pearson correlation coefficients. The height axis displays the distance among clusters. The heatmap’s y-axis represents clustering distance, with color intensity reflecting the strength of correlation. SL: Stem length, LL: Leaf length, LW: Leaf width, RL: Root length, FW: Fresh weight, DW: Dry weight, Chl a: Chlorophyll a, Chl b: Chlorophyll b, Chl T: Chlorophyll Total, Chl a.b: Chlorophyll a/ Chlorophyll b ratio, RWC: Relative water content of leaf, H₂O₂: Hydrogen peroxide, MDA: Malondialdehyde, PRO: Proline, Carbo: Carbohydrates, Pheno: Phenolics, Flavo: Flavonoids, Antho: Anthocyanin, DPPH: Antioxidant activity, CAT: Catalase, POD: Peroxidase, PPO: Polyphenol oxidase, APX: Ascorbate peroxidase