What Can Boron Deficiency Symptoms Tell Us about Its Function and Regulation?

Abstract

On the eve of the 100th anniversary of Dr. Warington’s discovery of boron (B) as a nutrient essential for higher plants, “boronists” have struggled to demonstrate a role beyond its structural function in cell walls dimerizing pectin molecules of rhamnogalacturonan II (RGII). In this regard, B deficiency has been associated with a plethora of symptoms in plants that include macroscopic symptoms like growth arrest and cell death and biochemical or molecular symptoms that include changes in cell wall pore size, apoplast acidification, or a steep ROS production that leads to an oxidative burst. Aiming to shed light on B functions in plant biology, we proposed here a unifying model integrating the current knowledge about B function(s) in plants to explain why B deficiency can cause such remarkable effects on plant growth and development, impacting crop productivity. In addition, based on recent experimental evidence that suggests the existence of different B ligands other than RGII in plant cells, namely glycolipids, and glycoproteins, we proposed an experimental pipeline to identify putative missing ligands and to determine how they would integrate into the above-mentioned model.

Plant Growth Regulation in Cell and Tissue Culture In Vitro

“…The primary functions of boron (B) relate to cell-to-cell communication and its structural role in the cell wall [ 60 ]. Its roles include involvement in membrane integrity, seed production, root elongation, and sugar metabolism [ 61 ]. Pioneering work on the boron deficiency effect was performed in 1920 [ 62 , 63 ].…”

Molecular, Metabolic and Physiological Responses to Boron Stress in Higher Plants

“…What Can Boron Deficiency Symptoms Tell Us about Its Function and Regulation? [26] B-deficient plants may exhibit a wide range of symptoms depending on the species and the developmental stage of the plant [27]. In recent years, the use of novel molecular tools has allowed for the discovery of novel functions and ligands of B in organisms including bacteria, animals, and plants.…”

“…Still, there is a general lack of knowledge regarding the specific functions of B, B stress signaling pathways, and B interactors beyond its structural role in the plant cell wall. Bolaños et al [26] proposed a model integrating B-deficiency symptoms and signaling pathways, summarizing the current knowledge regarding B putative ligands in plants.…”

B2O3 nanoparticles alleviate salt stress in maize leaf growth zones by enhancing photosynthesis and maintaining mineral and redox status

“…Further, B is involved in water relations, ion uptake and transport, and metabolism of carbohydrates and plant hormones (Karthika et al, 2018; Khan et al, 2018; Kumari et al, 2022). Thus, B deficiency resulted in growth retardation, stomatal conductance reduction and photosynthesis decline (Bolaños et al, 2023; Chen et al, 2022; Shah et al, 2017).…”