J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (3): 791-809.DOI: 10.1111/jipb.13389

• Molecular Physiology • Previous Articles     Next Articles

PuHox52 promotes coordinated uptake of nitrate, phosphate, and iron under nitrogen deficiency in Populus ussuriensis

Ming Wei1,2, Mengqiu Zhang1, Jiali Sun1, Ying Zhao1, Solme Pak1, Miaomiao Ma1, Yingxi Chen1, Han Lu2, Jingli Yang1, Hairong Wei3, Yuhua Li2,4* and Chenghao Li1*   

  1. 1. State Key Laboratory of Tree Genetics and Breeding, School of Forestry, Northeast Forestry University, Harbin 150040, China;
    2. College of Life Sciences, Northeast Forestry University, Harbin 150040, China;
    3. College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931, USA;
    4. Key Laboratory of Saline-alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin 150040, China
    *Correspondences: Chenghao Li (chli@nefu.edu.cn, Dr. Li is fully responsible for the distributions of the materials associated with this article); Yuhua Li (lyhshen@126.com)
  • Received:2022-06-06 Accepted:2022-10-11 Online:2022-10-13 Published:2023-03-01

Abstract: It is of great importance to better understand how trees regulate nitrogen (N) uptake under N deficiency conditions which severely challenge afforestation practices, yet the underlying molecular mechanisms have not been well elucidated. Here, we functionally characterized PuHox52, a Populus ussuriensis HD-ZIP transcription factor, whose overexpression greatly enhanced nutrient uptake and plant growth under N deficiency. We first conducted an RNA sequencing experiment to obtain root transcriptome using PuHox52-overexpression lines of P. ussuriensis under low N treatment. We then performed multiple genetic and phenotypic analyses to identify key target genes of PuHox52 and validated how they acted against N deficiency under PuHox52 regulation. PuHox52 was specifically induced in roots by N deficiency, and overexpression of PuHox52 promoted N uptake, plant growth, and root development. We demonstrated that several nitrate-responsive genes (PuNRT1.1, PuNRT2.4, PuCLC-b, PuNIA2, PuNIR1, and PuNLP1), phosphate-responsive genes (PuPHL1A and PuPHL1B), and an iron transporter gene (PuIRT1) were substantiated to be direct targets of PuHox52. Among them, PuNRT1.1, PuPHL1A/B, and PuIRT1 were upregulated to relatively higher levels during PuHox52-mediated responses against N deficiency in PuHox52-overexpression lines compared to WT. Our study revealed a novel regulatory mechanism underlying root adaption to N deficiency where PuHox52 modulated a coordinated uptake of nitrate, phosphate, and iron through ‘PuHox52-PuNRT1.1’, ‘PuHox52-PuPHL1A/PuPHL1B’, and ‘PuHox52-PuIRT1’ regulatory relationships in poplar roots.

Key words: HD-Zip transcription factor, iron transport, nitrate transport, nitrogen deprivation, phosphate absorption, Populus ussuriensis, root architecture, target gene

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