Boron transport in Eucalyptus. 2. Identification in silico of a putative boron transporter for xylem loading in eucalypt

Abstract

Boron (B) is a low mobility plant micronutrient whose molecular mechanisms of absorption and translocation are still controversial. Many factors are involved in tolerance to Boron excess or deficiency. Recently, the first protein linked to boron transport in biological systems, BOR1, was characterized in Arabidopsis thaliana. This protein is involved in boron xylem loading and is similar to bicarbonate transporters found in animals. There are indications that BOR1 is a member of a conserved protein family in plants. In this work, FORESTS database was used to identify sequences similar to this protein family, looking for a probable BOR1 homolog in eucalypt. We found five consensus sequences similar to BOR1; three of them were then used in multiple alignment analysis. Based on amino acid similarity and in silico expression patterns, a consensus sequence was identified as a candidate BOR1 homolog, helping deeper experimental assays that could identify the function of this protein family in Eucalyptus.

Boron in Plants: Deficiency and Toxicity

“…All of these findings demonstrate that BOR1 is an efflux‐type B transporter for xylem loading under low B limitation (Takano et al 2002). Other BOR1 ‐like genes have been identified in Eucalyptus (Domingues et al 2005) and rice (Nakagawa et al 2007).…”

Biologically active compounds of semi-metals

“…In it, Takano et al (2002) identified BOR1, a membrane protein with homology to bicarbonate transporters in animals as an efflux-type B transporter for xylem loading that is essential for protecting shoots from boron deficiency. A potential BOR1 homolog was found also in Eucalyptus (Domingues et al, 2005). Miwa et al (2006) generated Arabidopsis thaliana plants tolerating B-deficient conditions due to the overexpression of BOR1.…”

Boron: More Than an Essential Element for Land Plants?

“…In agreement with the differential activity of B transporters across distinct plant organs, it has been demonstrated that, with the aid of mathematical and computer science tools, the function of B transporters can be effectively predicted and experimentally validated in different species. For instance, by using the FORESTS database, a BOR1 homolog was found in Eucalyptus ( Domingues et al, 2005 ), whereas the recent usage of 18 different plant genomes allowed the identification of 80 and 34 homologs of BOR1 and NIP5;1, respectively ( Ozyigit et al, 2020 ). In addition, Kurt and Aydın (2020) identified and characterized five BOR1 transporters in potato ( Solanum tuberosum ) by using an in silico study.…”