Long-term boron-deficiency-responsive genes revealed by cDNA-AFLP differ between Citrus sinensis roots and leaves.

Yi-Bin Lu,Jinwook Lee,Lin-Tong Yang,Mei-Li Li,Yi-Ping Qi,Meng-Yang Jia,Xin Ye,Peng Guo,Li-Song Chen

doi:10.3389/fpls.2015.00585

Abstract

Seedlings of Citrus sinensis (L.) Osbeck were supplied with boron (B)-deficient (without H3BO3) or -sufficient (10 μM H3BO3) nutrient solution for 15 weeks. We identified 54 (38) and 38 (45) up (down)-regulated cDNA-AFLP bands (transcript-derived fragments, TDFs) from B-deficient leaves and roots, respectively. These TDFs were mainly involved in protein and amino acid metabolism, carbohydrate and energy metabolism, nucleic acid metabolism, cell transport, signal transduction, and stress response and defense. The majority of the differentially expressed TDFs were isolated only from B-deficient roots or leaves, only seven TDFs with the same GenBank ID were isolated from the both. In addition, ATP biosynthesis-related TDFs were induced in B-deficient roots, but unaffected in B-deficient leaves. Most of the differentially expressed TDFs associated with signal transduction and stress defense were down-regulated in roots, but up-regulated in leaves. TDFs related to protein ubiquitination and proteolysis were induced in B-deficient leaves except for one TDF, while only two down-regulated TDFs associated with ubiquitination were detected in B-deficient roots. Thus, many differences existed in long-term B-deficiency-responsive genes between roots and leaves. In conclusion, our findings provided a global picture of the differential responses occurring in B-deficient roots and leaves and revealed new insight into the different adaptive mechanisms of C. sinensis roots and leaves to B-deficiency at the transcriptional level.

Highlights

Boron (B), as an essential micronutrient required for higher plants, is absorbed from soil solution by plant roots mainly in the form of boric acid
Plant Growth and B Concentration in Roots and Leaves Seedlings treated without H3BO3 had slower growth and less leaf and root level of B than those treated with 10 μM H3BO3 (Figure S1)
B concentration in leaves from seedlings treated without H3BO3 was lower than the sufficient range of 30–100 μg g−1 dry weights (DWs) (Chapman, 1968)

Summary

Introduction

Boron (B), as an essential micronutrient required for higher plants, is absorbed from soil solution by plant roots mainly in the form of boric acid. B-deficiency causes remarkable alterations in the expression profiles of genes for various processes during plant growth and development, including cell wall modification (CamachoCristóbal et al, 2008b; Redondo-Nieto et al, 2012; Zhou et al, 2015), B uptake and translocation (Camacho-Cristóbal et al, 2008a), cell transport (Camacho-Cristóbal and González-Fontes, 2007; Redondo-Nieto et al, 2012; Zhou et al, 2015), vascular development (Yang et al, 2013a), stress response and defense (Redondo-Nieto et al, 2012; Zhou et al, 2015), protein and AA metabolism (Beato et al, 2010; Zhou et al, 2015), transcription, DNA metabolism, cell cycle, and signal transduction (RedondoNieto et al, 2012) in tobacco roots, leaves, and cells, citrus roots, and leaf veins, Medicago truncatula root nodules, Arabidopsis roots, shoots, and seedlings. Limited data are available on B-deficiency-responsive genes in woody plants

Methods

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Discussion

Conclusion