Identification and Functional Expression Pattern of NIP6;1, a Boric Acid Channel for Preferential Transport of Boron in Ternera Oil Palm

Abstract

Boron (B) is an essential micronutrient required for plant growth and development which affects not only yield but also the quality of crop. Boron deficiency is major agricultural problems worldwide and frequently observed because boric acid in soil is easily leached under high rainfall condition as found in oil palm (Elaeis guineensis Jacq.) plantation. Recent reports suggest that boron can be retranslocated from old tissues to young tissues or can be preferentially transported to sink tissues under boron deficiency. The objectives of this study were to clone full length of EgNIP6;1 gene and study the expression pattern of EgNIP6;1 gene in oil palm during boron deficiency boron sufficiency and toxicity treatment using real–time PCR technique. In this study we cloned an NIP6;1–like gene (named as EgNIP6;1) from Tenera oil palm. The full length of EgNIP6;1 was 858 bp and encoded a protein of 285 amino acid residues. The phylogenetic tree analysis indicated that EgNIP6;1 protein belonged to NIPs subgroup II. Sequence analysis showed the EgNIP6;1 was highly conserved with NIP in other plant species such as date palm, cotton, Arabidopsis, and soybean. For the expression pattern analysis, root and leaves samples were collected randomly at 7, 14, 28 and 56 days after boron deficiency, boron sufficiency and boron toxicity treatment. The result showed the EgNIP6;1 expression level in leaves was induced and increased at 7 and 28 days after boron deficiency treatment as compared with that 0 day (control) and mainly expressed in leave as compared with root.