Aluminum toxicity could be mitigated with boron by altering the metabolic patterns of amino acids and carbohydrates rather than organic acids in trifoliate orange

Abstract

Aluminum (Al) toxicity is the main constraint of root growth and productivity on arable acidic soil. Although boron (B) is used to ameliorate Al stress, the exact mechanisms underlying the effects of B on Al-induced alteration on root metabolites are poorly understood, especially in the trifoliate orange, which is an important rootstock in China. Therefore, a hydroponics experiment was conducted to explore the mechanisms of B mitigates Al toxicity in roots of citrus by metabolomics. A total of 60 metabolites were identified and analyzed in the present study. The 17 amino acids and 8 sugars were up-regulated in Al-treated roots, mainly histidine, cycloleucine, asparagine, citrulline, raffinose and trehalose, and increased by 38.5-, 8.7-, 6.0-, 6.0-, 7.5- and 6.6-fold, respectively. Meanwhile, significant down-regulation of aspartic acid, isoleucine, glutamic acid and six sugars were indicated under Al stress. Aluminum induced a decrease of nine organic acids, especially l-malic acid, citric acid and threonic acid, by 98.2, 93.6 and 95.1%, respectively. Interestingly, in the presence of Al, B application decreased the contents of asparagine, cycloleucine, citrulline and histidine as well as myo-inositol, raffinose, galactinol and 3,6-anhydro-d-galactose by 52.2, 57.4, 46.7, 63.0, 65.4, 74.3, 62.5 and 55.0%, respectively. However, there was no obvious difference in the organic acid contents in Al-stressed roots treated with B. Conclusively, our results show that B regulates the metabolic patterns of amino acids and carbohydrates and reduces Al toxicity. Nevertheless, B addition did not affect the Al-induced changes in the metabolic modes of organic acids.

Silicon- and Boron-Induced Physio-Biochemical Alteration and Organic Acid Regulation Mitigates Aluminum Phytotoxicity in Date Palm Seedlings

“…The deficiency of B in plants leads to many deformities in plants, such as root growth inhibition; the induction of chlorotic disorders in leaves; a reduction in yield; and the impairment of the cellular components, structure, and composition of the cell wall [ 31 , 32 , 33 ]. Similarly, the alleviation of Al3+-induced stress by the exogenous treatment of B in different plants has been reported previously by many researchers in different plants [ 29 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ]. Moreover, these studies have suggested that B possibly overcomes the consequences of Al 3+ toxicity by restricting Al binding sites.…”

Effects of Elevated Aluminum Concentration and Distribution on Root Damage, Cell Wall Polysaccharides, and Nutrient Uptake in Different Tolerant Eucalyptus Clones

“…Plants have evolved various levels of tolerance to Al toxicity. Therefore, cultivating Al-tolerant plants is an effective way to sustainably and efficiently detoxify acidic soils containing Al [ 24 ]. Silviculture practices require trees that not only have high yield but also good environmental adaptability [ 25 ].…”

The Oxidative Damage and Morphological Changes of Sugar Beet (Beta vulgaris L.) Leaves at Seedlings Stage Exposed to Boron Deficiency in Hydroponics

“…The B content and BA of shoot were higher than the roots under normal B treatment and B deficiency s. Studies found that under normal B supply conditions, B absorbed is transported through the lower ground parts to shoot, whereas the B transport coefficient tends to decrease in its transport capacity with B deficiency and plants preferentially allocate B to the shoot under B deficient conditions (Yan et al 2019a).…”