Genome-Wide Characterization and Evolutionary Expansion of Poplar NAC Transcription Factors and Their Tissue-Specific Expression Profiles under Drought

Int J Mol Sci. 2022 Dec 23;24(1):253. doi: 10.3390/ijms24010253.

Abstract

The NAC (NAM, ATAF1/2 and CUC2) is a large gene family of plant-specific transcription factors that play a pivotal role in various physiological processes and abiotic stresses. Due to the lack of genome-wide characterization, intraspecific and interspecific synteny, and drought-responsive expression pattern of NAC genes in poplar, the functional characterization of drought-related NAC genes have been scarcely reported in Populus species. Here, we identified a total of 170 NAC domain-containing genes in the P. trichocarpa genome, 169 of which were unevenly distributed on its nineteen chromosomes. These NAC genes were phylogenetically divided into twenty subgroups, some of which exhibited a similar pattern of exon-intron architecture. The synteny and Ka/Ks analysis indicated that the expansion of NAC genes in poplar was mainly due to gene duplication events occurring before and after the divergence of Populus and Salix. Ten PdNAC (P. deltoids × P. euramericana cv.'Nanlin895') genes were randomly selected and cloned. Their drought-responsive expression profiles showed a tissue-specific pattern. The transcription factor PdNAC013 was verified to be localized in the nucleus. Our research results provide genomic information for the expansion of NAC genes in the poplar genome, and for further characterizing putative poplar NAC genes associated with water-deficit.

Keywords: NAC genes; Populus; drought-responsive; gene duplication events.

MeSH terms

  • Biological Evolution
  • Droughts
  • Gene Duplication
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant
  • Phylogeny
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Populus* / genetics
  • Populus* / metabolism
  • Stress, Physiological / genetics
  • Transcription Factors* / genetics
  • Transcription Factors* / metabolism

Substances

  • Transcription Factors
  • Plant Proteins

Grants and funding

This research was funded by grants from grants from ‘Fourteen Five-Year’ National Science and Technology Support Program (Grant No.2021YFD2201200), and Natural Science Foundation of Jiangsu Province (Grant No. BK20150879). The funding bodies did not have a role in the design of the study, data collection, analysis, interpretation of data, writing the manuscript, nor the decision to publish.