The effect of boron availability, CO2, and irradiance on relative accumulation of the major boron transport proteins, BOR1 and NIP5;1

• Published in: Biologia plantarum Vol. 62; no. 1; pp. 121 - 128
• Main Authors: Mishra, S., Heckathorn, S. A., Frantz, J. M., Krause, C.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2018; Springer Nature B.V; Institute of Experimental Botany of the Czech Academy of Sciences
• Subjects: Accumulation; Antibodies; arabidopsis thaliana; Availability; azolla caroliniana; b uptake; Biomedical and Life Sciences; Boron; Carbon dioxide; Efflux; Environmental factors; Enzyme-linked immunosorbent assay; Gene expression; hordeum vulgare; Irradiance; Life Sciences; mRNA; Original Papers; pelargonium × hortorum; photosynthesis; Plant Sciences; Protein transport; Proteins; Species; Sugar; Western blotting; Xylem; B uptake; photosynthesis; ×
• ISSN: 0006-3134; 1573-8264
• DOI: 10.1007/s10535-017-0744-5

Boron (B) is an essential plant micronutrient. Two major B-transport proteins have been recently identified and partially characterized: BOR1, a high-affinity B efflux transporter involved in xylem loading, and NIP5;1, a plasma-membrane boric-acid channel involved in B uptake. To date, studies of these B transporters have investigated their expression individually (mainly as mRNA), and only in response to variation in B availability (mostly B deficiency); the influence of other factors, such as plant resource status, has not been studied. To address this, we grew geranium ( Pelargonium × hortorum cv. Maverick White) plants under ambient or elevated CO 2 concentration, different sub-saturating irradiances, and different B availability. For comparison we also grew three other species ( Arabidopsis thaliana , Azolla caroliniana , and Hordeum vulgare ) under broad range of B supply. Relative accumulation of BOR1 and NIP5;1 proteins were measured using protein-specific antibodies and Western blotting or ELISA. Elevated CO 2 significantly increased content of NIP5;1, while increases in irradiance increased BOR1 content, but decreased NIP5;1 content. Across species, content of both transporters often decreased with increasing B availability, but sometimes remained unchanged or even increased, depending on CO 2 , irradiance, species, or transporter. Content of BOR1 and NIP5;1 was correlated with root proteins, B content, and sugar content (for high CO 2 only), as well as B uptake, but CO 2 and irradiance often affected these relationships. Thus, relative accumulation of BOR1 and NIP5;1 is influenced not only by B content, as expected, but by other environmental factors as well.