NtbZIP60, an endoplasmic reticulum-localized transcription factor, plays a role in the defense response against bacterial pathogens in Nicotiana tabacum

• Published in: Journal of plant research Vol. 121; no. 6; pp. 603 - 611
• Main Authors: Tateda, C.(Tohoku Univ., Sendai (Japan)), Ozaki, R, Onodera, Y, Takahashi, Y, Yamaguchi, K, Berberich, T, Koizumi, N, Kusano, T
• Format: Journal Article
• Language: English
• Published: Japan Springer Japan 01.11.2008; Springer Nature B.V
• Subjects: AGENT PATHOGENE; Amino Acid Sequence; ARABIDOPSIS THALIANA; BACTERIA; Basic-Leucine Zipper Transcription Factors - genetics; Basic-Leucine Zipper Transcription Factors - metabolism; Biomedical and Life Sciences; Cloning, Molecular; DEFENCE MECHANISMS; ENDOPLASMIC RETICULUM; Endoplasmic Reticulum - metabolism; ESPERMINA; FACTEUR DE TRANSCRIPTION; FACTORES DE TRANSCRIPCION; Gene Silencing; Host-Pathogen Interactions; Immunity, Innate; Life Sciences; MECANISME DE DEFENSE; MECANISMOS DE DEFENSA; Molecular Sequence Data; Nicotiana - genetics; Nicotiana - immunology; Nicotiana - metabolism; Nicotiana - microbiology; Nicotiana benthamiana; NICOTIANA TABACUM; ORGANISMOS PATOGENOS; PATHOGENS; Plant Biochemistry; Plant biology; Plant Ecology; Plant Physiology; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Sciences; Proteins; Pseudomonas - immunology; Pseudomonas cichorii; Pseudomonas syringae; Regular Paper; RETICULO ENDOPLASMATICO; RETICULUM ENDOPLASMIQUE; Signal Transduction; SPERMINE; Spermine - metabolism; TABAC; TABACO; TOBACCO; TRANSCRIPTION FACTORS; Transcriptional Activation; Up-Regulation; Bacterial pathogen; Spermine; Transcription factor; Endoplasmic reticulum; Defense
• ISSN: 0918-9440; 1618-0860
• DOI: 10.1007/s10265-008-0185-5

A spermine-based signal transduction pathway plays a defensive role against incompatible pathogens. We identified a novel spermine-responsive cDNA from Nicotiana tabacum that encodes a basic region/leucine zipper protein with a putative transmembrane domain. Identity to Arabidopsis thaliana AtbZIP60 was sufficiently high to name the novel cDNA NtbZIP60. Expression analysis revealed that NtbZIP60 is a component of the spermine-signal pathway, and is also involved in the unfolded protein response (UPR), as demonstrated for AtbZIP60. The gene product, NtbZIP60, localizes to the endoplasmic reticulum (ER) in plant cells; once the putative transmembrane domain is eliminated from the intact protein, it targets the nucleus. The putative processed form of NtbZIP60 transactivates target genes through binding to plant-specific UPR cis-elements. Expression of NbbZIP60, an NtbZIP60 ortholog in Nicotiana benthamiana, was significantly up-regulated at 6 h and later time points upon infection with the non-host pathogen Pseudomonas cichorii, while it was unaffected by infection with the compatible pathogen Pseudomonas syringae pv. tabaci. Furthermore, NbbZIP60-silenced N. benthamiana plants allowed higher multiplication of P. cichorii compared to the control plants. Taken together, the results suggest that this ER-localized transcription factor is involved in the spermine-signal transduction pathway and plays an important role in plant innate immunity.