Open AccessPp NAC 1 , a main regulator of phenylalanine biosynthesis and utilization in maritime pine
Author(s) -
Pascual María Belén,
Llebrés MaríaTeresa,
CravenBartle Blanca,
Cañas Rafael A.,
Cánovas Francisco M.,
Ávila Concepción
Publication year - 2018
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.12854
Subject(s) - biology , xylem , pinus pinaster , regulator , transactivation , gene , transcription factor , transcriptional regulation , secondary metabolism , biogenesis , microbiology and biotechnology , biosynthesis , biochemistry , secondary cell wall , phenylalanine , botany , amino acid
Summary The transcriptional regulation of phenylalanine metabolism is particularly important in conifers, long‐lived species that use large amounts of carbon in wood. Here, we show that the Pinus pinaster transcription factor, Pp NAC 1, is a main regulator of phenylalanine biosynthesis and utilization. A phylogenetic analysis classified Pp NAC 1 in the NST proteins group and was selected for functional characterization. Pp NAC 1 is predominantly expressed in the secondary xylem and compression wood of adult trees. Silencing of Pp NAC 1 in P. pinaster results in the alteration of stem vascular radial patterning and the down‐regulation of several genes associated with cell wall biogenesis and secondary metabolism. Furthermore, transactivation and EMSA analyses showed that Pp NAC 1 is able to activate its own expression and PpMyb4 promoter, while PpMyb4 is able to activate PpMyb8 , a transcriptional regulator of phenylalanine and lignin biosynthesis in maritime pine. Together, these results suggest that Pp NAC 1 is a functional ortholog of the Arabidopsis SND 1 and NST 1 genes and support the idea that key regulators governing secondary cell wall formation could be conserved between gymnosperms and angiosperms. Understanding the molecular switches controlling wood formation is of paramount importance for fundamental tree biology and paves the way for applications in conifer biotechnology.