Abstract Boron (B) is an essential plant micronutrient but studies regarding its transport are still limited to a few plants. This work identified two major B transport sequences in plants, NIP5;1 boric acid channel protein and BOR1 transporter. 80 BOR1 and 34 NIP5;1 homologs were identified in 18 different plant genomes. BOR1 homologs had a HCO3-transporter domain, 649–737 amino-acid residues with mainly basic nature, putative 8–11 transmembrane domains (TMDs) and 11–13 exons. NIP5;1 homologs had a MIP family domain, 294–311 amino-acid residues with basic nature, 5–6 putative TMDs and 3–5 exons. Tyrosine-based motif, acidic di-leucine motif and lysine residue, reported for polarity, vacuolar sorting and B-dependent degradation, were identified in BOR1 homologs. Two NPA motifs and an ar/R selectivity filter with AIGR residues, reportedly essential in B transport, were also found in NIP5;1 homologs. Two NPA motifs in AtNIP5;1 and OsNIP3;1 homologs were NPS and NPV, whereas in sequences homologous to AtNIP6;1 were NPA/V. Besides, ar/R selectivity filters were identified with A(N/S/T)IGR residues in NIP5;1 and NIP3;1 homologs. The BOR1 and NIP5;1 model structures were mainly conserved. Under different perturbations, Arabidopsis thaliana NIP5;1 and NIP6;1 genes demonstrated similar expression patterns although they act in different tissues, suggesting a common regulatory mechanism, whereas BOR1 showed a different expression pattern. BOR1 was substantially expressed in primary root, radicle and flower; NIP5;1 in primary root and roots, and NIP6;1 in petiole. NIP5;1, 6;1 and BOR1 expression in other plant organs implied their involvement in different pathways in addition to B uptake and its mobilization.

中文翻译：

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不同植物基因组中两个主要硼转运基因BOR1和NIP5;1的探索

摘要 硼 (B) 是一种必需的植物微量营养素，但对其转运的研究仍仅限于少数植物。这项工作确定了植物中的两个主要 B 转运序列，NIP5；1 硼酸通道蛋白和 BOR1 转运蛋白。在 18 个不同的植物基因组中鉴定了 80 个 BOR1 和 34 个 NIP5;1 同源物。BOR1 同源物具有 HCO3 转运蛋白结构域、649-737 个氨基酸残基，主要具有碱性，推定的 8-11 个跨膜结构域 (TMD) 和 11-13 个外显子。NIP5;1 同源物具有 MIP 家族结构域、294-311 个具有碱性的氨基酸残基、5-6 个推定的 TMD 和 3-5 个外显子。在 BOR1 同源物中鉴定了基于酪氨酸的基序、酸性双亮氨酸基序和赖氨酸残基，报告极性、液泡分选和 B 依赖性降解。两个 NPA 基序和一个带有 AIGR 残基的 ar/R 选择性过滤器，据报道，在 B 运输中必不可少，也在 NIP5;1 同源物中发现。AtNIP5;1 和 OsNIP3;1 同源物中的两个 NPA 基序是 NPS 和 NPV，而在与 AtNIP6;1 同源的序列中是 NPA/V。此外，ar/R 选择性过滤器在 NIP5;1 和 NIP3;1 同系物中被鉴定为 A(N/S/T)IGR 残基。BOR1和NIP5;1模型结构主要是保守的。在不同的扰动下，拟南芥 NIP5;1 和 NIP6;1 基因表现出相似的表达模式，尽管它们在不同的组织中起作用，表明具有共同的调控机制，而 BOR1 则表现出不同的表达模式。BOR1在初生根、胚根和花中大量表达；NIP5;1 在初生根和根中，NIP6;1 在叶柄中。NIP5;1, 6;