5-Aminolevulinic acid mitigates the chromium-induced changes in Helianthus annuus L. as revealed by plant defense system enhancement

• Published in: Plant physiology and biochemistry 2023-05, Vol.198, p.107701-107701, Article 107701
• Main Authors: Xu, Zishu, Pan, Jianmin, Ullah, Najeeb, Duan, Yi, Hao, Ruiyong, Li, Juanjuan, Huang, Qian, Xu, Ling
• Format: Article
• Language: English
• Subjects: 5-Aminolevolinic acid; Accumulation of chromium; Aminolevulinic Acid - metabolism; Aminolevulinic Acid - pharmacology; Biodegradation, Environmental; Chromium - toxicity; EDDS; Helianthus - metabolism; Helianthus annuus L; Metals, Heavy - metabolism; Soil; Soil Pollutants - analysis; Soil Pollutants - toxicity; Synergistic effect
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2023.107701

Chromium (Cr) in the soil is one of the major pollutants for agricultural production. This study examined the efficiency of sunflower plants to remediate Cr-contaminated soils using a plant growth regulator, 5-aminolevolinic acid (ALA). At six leaf stage, sunflower plants were exposed to soil-applied Cr (0.15 g kg−1), manganese (Mn, 0.3 g kg−1) and trisodium (S,S)-ethylenediamine-N,N′-disuccinic acid (EDDS, 2.5 mmol kg−1), ALA (10 mg L−1) was sprayed. After ALA treatment, the plants were harvested for further biochemical analyses. Results showed that EDDS and Mn improved the Cr accumulation but restrained plant growth. Conversely, ALA improved the growth of Cr-stressed plants by promoting chlorophyll concentration in the top fully expanded leaves. The bioaccumulation quantity and removal efficiency of sunflowers treated by Cr + EDDS + ALA was improved by 47.92% and 47.94%, respectively, as compared to the Cr treatment. This was further supported by qRT-PCR analysis, where the expression of heavy metal transport genes such as ZIP6 and NRAMP6 and subsequently Cr accumulation in sunflower tissues increased by EDDS, Mn, and ALA application. However, compared with other treatments, ALA ameliorated cellular injury from Cr-stress by uptake or movement of Cr prevention, modulation of antioxidant enzymes, and elimination of reactive oxygen species. Our study suggested that ALA as an ideal option for the phytoremediation of Cr-contaminated soils. •ALA significantly protected sunflower from Cr and chelators stresses.•ALA protected plants by reducing the accumulation of Cr in sunflower and provoking antioxidant mechanisms.•Effects of Mn and ALA on protection of sunflower under Cr stress by promoting chlorophyll synthesis and reducing ROS accumulation.•The growth of plants is inhibited by Cr stress, which disrupts normal metabolism by damaging cell structures.