PuC3H35 confers drought tolerance by enhancing lignin and proanthocyanidin biosynthesis in the roots of Populus ussuriensis

Abstract

Since the roots are the very organ where plants first sense and respond drought stress, it is of great importance to better understand root responses to drought. Yet the underlying molecular mechanisms governing root responses to drought stress have been poorly understood.Here, we identified and functionally characterized a CCCH type transcription factor, PuC3H35, and its targets, anthocyanin reductase (PuANR) and early Arabidopsis aluminum induced1 (PuEARLI1), which are involved in mediating proanthocyanidin (PA) and lignin biosynthesis in response to drought stress in Populus ussuriensis root.PuC3H35 was root-specifically induced upon drought stress. Overexpressing PuC3H35 promoted PA and lignin biosynthesis and vascular tissue development, resulting in enhanced tolerance to drought stress by the means of anti-oxidation and mechanical supporting. We further demonstrated that PuC3H35 directly bound to the promoters of PuANR and PuEARLI1 and overexpressing PuANR or PuEARLI1 increased root PA or lignin levels, respectively, under drought stress.Taken together, these results revealed a novel regulatory pathway for drought tolerance, in which PuC3H35 mediated PA and lignin biosynthesis by collaboratively regulating 'PuC3H35-PuANR-PA' and 'PuC3H35-PuEARLI1-PuCCRs-lignin' modules in poplar roots.

Characterization of the Gene Expression Profile Response to Drought Stress in Populus ussuriensis Using PacBio SMRT and Illumina Sequencing

“…As the main component of the secondary cell wall, lignin plays an important role in plant resistance to drought stress [ 65 , 66 ]. Recently, it has been demonstrated that the increase in lignin enhanced the tolerance of P. ussuriensis to drought stress [ 67 ]. The lignin monomers were carried out through the phenylpropanoid biosynthesis pathway.…”

OsGRP3 Enhances Drought Resistance by Altering Phenylpropanoid Biosynthesis Pathway in Rice (Oryza sativa L.)

“…Phenylpropanoid metabolism contributes to plant development and plant-environment interactions [31][32][33]. Two major products of the phenylpropanoid biosynthesis pathway, lignin [34][35][36][37] and flavonoids [38], have been reported to positively regulate drought resistance. As a main component of the cell wall, lignin plays an important role in mechanical support and water transport in plants [39,40].…”

“…Researches have revealed that upregulating the expression of genes involved in lignin biosynthesis, such as phenylalanine ammonia lyase (PAL) in Nicotiana tabacum [42], CAD2 and CAD3 in Cucumis melo [43], or promoting the activities of enzymes involved in lignin biosynthesis, such as MePOD and MeCAD15 in Manihot esculenta [34], leads to the accumulation of lignin, which helps plants to fight against drought stress. Moreover, overexpressing other genes that were not in the phenylpropanoid pathway, such as IbLEA14 in Ipomoea batatas [44], PuC3H35 in Populus ussuriensis [35], OsTF1L and OsERF71 in rice [45,46], also resulted in the deposition of lignin and enhanced drought tolerance.…”

Overexpression of Pennisetum purpureum CCoAOMT Contributes to Lignin Deposition and Drought Tolerance by Promoting the Accumulation of Flavonoids in Transgenic Tobacco

“…Many studies have shown that lignin biosynthesis is enhanced under drought stress and in response to other abiotic stressors. Lignin content significantly increases in the stem when plants are exposed to drought stress ( Hu et al, 2009 ; Moura-Sobczak et al, 2011 ; Geng et al, 2018 ; Li et al, 2022 ). Moreover, an increase in lignin deposition is required for drought tolerance ( Hu et al, 2009 ; Srivastava et al, 2015 ; Geng et al, 2018 ; Zhou et al, 2020 ) and the metal ion response ( Xia et al, 2018 ; Su et al, 2020 ) via overexpression of lignin biosynthesis-related genes.…”

“…Moreover, an increase in lignin deposition is required for drought tolerance ( Hu et al, 2009 ; Srivastava et al, 2015 ; Geng et al, 2018 ; Zhou et al, 2020 ) and the metal ion response ( Xia et al, 2018 ; Su et al, 2020 ) via overexpression of lignin biosynthesis-related genes. For example, increased lignin content and improved drought tolerance are caused by the overexpression of genes such as PoCCoAOMT in Nicotiana tabacum ( Zhao et al, 2021 ), Gh4CL7 in Arabidopsis thaliana ( Sun S. C. et al, 2020 ), PtoMYB170 in Populus tomentosa ( Xu et al, 2017 ), and PuC3H35 in Populus ussuriensi s ( Li et al, 2022 ).…”