Molecular regulation of aluminum resistance and sulfur nutrition during root growth

Abstract

Aluminum toxicity and sulfate deprivation both regulate microRNA395 expression, repressing its low-affinity sulfate transporter ( SULTR2;1 ) target. Sulfate deprivation also induces the high-affinity sulfate transporter gene ( SULTR12 ), allowing enhanced sulfate uptake. Few studies about the relationships between sulfate, a plant nutrient, and aluminum, a toxic ion, are available; hence, the molecular and physiological processes underpinning this interaction are poorly understood. The Al-sulfate interaction occurs in acidic soils, whereby relatively high concentrations of trivalent toxic aluminum (Al) may hamper root growth, limiting uptake of nutrients, including sulfur (S). On the other side, Al may be detoxified by complexation with sulfate in the acid soil solution as well as in the root-cell vacuoles. In this review, we focus on recent insights into the mechanisms governing plant responses to Al toxicity and its relationship with sulfur nutrition, emphasizing the role of phytohormones, microRNAs, and ion transporters in higher plants. It is known that Al disturbs gene expression and enzymes involved in biosynthesis of S-containing cysteine in root cells. On the other hand, Al may induce ethylene biosynthesis, enhance reactive oxygen species production, alter phytohormone transport, trigger root growth inhibition and promote sulfate uptake under S deficiency. MicroRNA395, regulated by both Al toxicity and sulfate deprivation, represses its low-affinity Sulfate Transporter 2;1 (SULTR2;1) target. In addition, sulfate deprivation induces High Affinity Sulfate Transporters (HAST; SULTR1;2), improving sulfate uptake from low-sulfate soil solutions. Identification of new microRNAs and cloning of their target genes are necessary for a better understanding of the role of molecular regulation of plant resistance to Al stress and sulfate deprivation.

Machine Learning Unmasked Nutritional Imbalances on the Medicinal Plant Bryophyllum sp. Cultured in vitro

“…This could be suggested according to the model results, since low RL, PN and AFW values were observed under low SO 2− 4 concentrations and high MoO 2− 4 concentrations, and conversely, RL, PN and AFW values were high under high SO 2− 4 concentrations and low MoO 2− 4 concentrations ( Table 4). In the case of RL, sulfate plays a positive role, by promoting root biomass accumulation and nutrient uptake during root growth (Alarcón-Poblete et al, 2018), in agreement with the results describe here for RFW (Table 3). These observations indicate that sulfur is essential for in vitro root development on Bryophyllum spp., although molybdate at mid concentrations may assist to its function when sulfate is limited, as demonstrated for BT (rules 14, 40, and 72; Table 4), and reported by other authors (Alhendawi et al, 2005;Shinmachi et al, 2010).…”

The Role of Symbiotic Microorganisms, Nutrient Uptake and Rhizosphere Bacterial Community in Response of Pea (Pisum sativum L.) Genotypes to Elevated Al Concentrations in Soil

“…Our original observation is that inoculation increased nutrient concentrations in the rhizosphere, particularly counteracting the decrease in Mo, P and S concentrations in the rhizosphere of Al-treated plants. Molybdenum is an important element for nitrogen fixation being a cofactor of nitrogenase [67], whereas P [68,69] and S [70] are crucial elements for Al tolerance in plants.…”

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

“…After silicon and oxygen, aluminum (Al) is considered as one of the most abundant elements on the earth’s crust, occurring in the form of silicates or other deposits [ 1 , 2 ]. The accumulation of Al in acidic soil (with a pH of 5.5 or lower) converts it into a phytotoxic form of Al 3+ , which negatively influences the plant root system and subsequently ruins the aerial parts of plants due to immediate root deterioration [ 3 , 4 , 5 , 6 ]. The toxicity of Al 3+ in roots inhibits cell division and elongation, causing root apices to be swollen and leading to poor or no root-hair development, oxidative damage, and the impairment of several pathways responsible for signal transduction [ 7 , 8 , 9 ].…”