Inoculation of endophytic bacteria improves nutritional and antioxidant profiles in hydroponic sweet pepper
Disinfection, a practice in hydroponic systems to eliminate harmful microbes, inadvertently remove beneficial bacteria, leaving the systems vulnerable to microbial imbalances. Introducing beneficial endophytic bacteria in these systems may enhance the plant's health by improving nutrient uptake...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-06-01
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| Series: | Heliyon |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2405844025018195 |
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| Summary: | Disinfection, a practice in hydroponic systems to eliminate harmful microbes, inadvertently remove beneficial bacteria, leaving the systems vulnerable to microbial imbalances. Introducing beneficial endophytic bacteria in these systems may enhance the plant's health by improving nutrient uptakes and synthesis of bioactive molecules. Thus, this study aimed to assess the effects of 10 different inocula on vitamin contents, polyphenols, and antioxidant properties of sweet peppers. The vitamins included were B1 (thiamine), B2 (riboflavin), E (tocopherols) and the vitamin C redox couple. Thiamine levels were most affected by the endophytes. Plantibacter flavus-A inoculum (SP3) produced the highest thiamine concentration (0.41 ± 0.08 μg/g fresh weight (FW)) which was 57 % higher relative to control plants (0.26 ± 0.06 μg/g FW). The consortia, SP9 (P. flavus-B, Paenibacillus taichungensis, and Rhizobium selenitireducens) and SP10 (P. flavus-A and P. flavus-B), also up-regulated thiamine levels. The higher vitamin C redox couple of Burkholderia phytofirmans inoculum (SP, 3.3 ± 0.7, p < 0.05) relative to control suggests a decreased oxidative stress. In contrast, the lower value of SP8 (Methylobacterium aerolatum) (0.3 ± 0.1, p < 0.05) suggests an increased oxidative stress. The inoculum SP5 (P. taichungensis) and the consortium SP9 enhanced total polyphenols, hydroxycinnamic acid derivatives, total flavonoids, or flavonols (p < 0.05) compared to control plants, and were also associated with higher ROO•, HO• and ABTS•+ radical scavenging data. Conversely, the consortium SP9 reduced total flavonoids and their sub-classes (p < 0.05) which was associated with increased oxidative stress and decreased ROO• scavenging activity. Overall, the effects of the endophytes on sweet pepper activities are dependent on both the strain and the metabolite. SP5 and the consortium SP9 are the most promising for the hydroponic growth of sweet pepper due to their enhancing effects on the plant redox system, biosynthesis of polyphenols, and radical scavenging capacities. |
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| ISSN: | 2405-8440 |