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Change in lignin structure, but not in lignin content, in transgenic poplar overexpressing the rice master regulator of secondary cell wall biosynthesis
Author(s) -
Tsuji Yukiko,
Takata Naoki,
Sakamoto Shingo,
NakagawaIzumi Akiko,
Taniguchi Toru,
Ralph John,
Mitsuda Nobutaka,
Kajita Shinya
Publication year - 2018
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12684
Subject(s) - lignin , secondary cell wall , cell wall , xylem , transgene , secondary growth , genetically modified rice , arabidopsis , polysaccharide , genetically modified crops , oryza sativa , chemistry , transcription factor , botany , microbiology and biotechnology , gene , biochemistry , biology , mutant
We previously succeeded in enhancing wood formation of wood in transgenic poplar plants by overexpressing secondary wall NAM/ATAF/CUC (NAC) domain protein 1 from Oryza sativa ( OsSWN1 ), a transcription factor ‘master regulator’ of secondary cell wall formation in rice, under control of the fiber preferential NST3/SND1 promoter from Arabidopsis. Transgenic plants had an increased cell wall thickness and cell wall density of individual cells in the secondary xylem of stems as well as an increased wood density. OsSWN1 triggers the induction of polysaccharide and lignin biosynthetic gene expressions, however, resulting in no significant impact on the lignin content in the transgenic plants. In contrast, wet and dry chemical analyses of lignin revealed changes in S/G ratio and in the composition of lignin interunit linkages in transgenic lines. The results from gene expression analysis suggest that the structural changes in lignin were due to an unbalanced induction of lignin biosynthetic genes in transgenic lines. Our present data indicate that the overexpression of the chimeric transcription factor causes accelerated deposition of secondary cell wall components including lignin and polysaccharides through an acquired mechanism.