Plant Cell Reports

, Volume 33, Issue 10, pp 1673–1686

Citrullus colocynthis NAC transcription factors CcNAC1 and CcNAC2 are involved in light and auxin signaling

Original Paper

DOI: 10.1007/s00299-014-1646-z

Cite this article as:
Wang, Z., Rashotte, A.M. & Dane, F. Plant Cell Rep (2014) 33: 1673. doi:10.1007/s00299-014-1646-z

Abstract

Key message

Two novel NAC transcription factors from Citrullus colocynthisimplicated in light and auxin signaling pathway.

Abstract

NAC transcription factors (NAM, ATAF1, 2, CUC2) have multiple functions in plant growth and development. Two NACs, CcNAC1 and CcNAC2, were recently identified in the highly drought-tolerant cucurbit species, Citrullus colocynthis. This study examines the functional role of these genes under different qualities of light based on the in silico analysis of the CcNAC1 and CcNAC2 promoters that revealed the presence of several light-associated motifs. The impact of both light and auxin on CcNAC1 and CcNAC2 expression was examined in C. colocynthis leaves, and using reporter (pCcNAC1, 2::GUS) lines in Arabidopsis. Furthermore, the effects of constitutive overexpression (OE-CcNAC1, 2) in Arabidopsis were also examined under a range of conditions to confirm reporter line linkages. White, blue, red, and far-red light treatments resulted in similar patterns of quantitative changes in CcNAC1and CcNAC2 expression in both species, with the highest transcript increases following red light. Photomorphogenic changes in Arabidopsis hypocotyls were correlated with gene transcript levels. In the absence of light, hypocotyls of OE-CcNAC1/CcNAC2 lines were significantly longer as compared to WT. The addition of exogenous auxin (+IAA) to growth medium also resulted in changes to the hypocotyl lengths of overexpression lines and spatiotemporal reporter line changes in seedlings. Our data suggest that CcNAC1, 2 might be functionally important in the light signaling pathway, and appear connected to the hormone auxin. This is the first study to indicate that NAC genes might play a role in both light and auxin signaling pathways.

Keywords

Citrullus colocynthis NAC Transcription factors Promoters Light Auxin CcNAC1 CcNAC2 

Abbreviations

ABA

Abscisic acid

B

Blue light

Cc

Citrullus colocynthis

cry

Cryptochrome

FR

Far-red light

GUS

Beta-d-glucuronidase

IAA

Indole-3-acetic acid

4-MU

4-Methylumbelliferone

NAC

NAM (No apical meristem), ATAF1, 2 (Arabidopsis thaliana activating factor 1, 2), CUC (no apical meristem)

OE

Overexpression

Phy

Phytochrome

PIFs

Phytochrome-interacting factors

Pfr

Far-red light-absorbing form

Pr

Red light-absorbing form

R

Red light

qRT-PCR

Quantitative real-time polymerase chain reaction

WT

Wild type

Supplementary material

299_2014_1646_MOESM1_ESM.docx (592 kb)
Supplementary material 1 (DOCX 591 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of HorticultureAuburn UniversityAuburnUSA
  2. 2.Department of Biological SciencesAuburn UniversityAuburnUSA

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