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Strong decrease in lignin content without significant alteration of plant development is induced by simultaneous down‐regulation of cinnamoyl CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD) in tobacco plants
Author(s) -
Chabannes Matthieu,
Barakate Abdellah,
Lapierre Catherine,
Marita Jane M.,
Ralph John,
Pean Michel,
Danoun Saïda,
Halpin Claire,
GrimaPettenati Jacqueline,
Boudet Alain Michel
Publication year - 2001
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2001.01140.x
Subject(s) - cinnamyl alcohol dehydrogenase , monolignol , transgene , lignin , nicotiana tabacum , biology , ectopic expression , biochemistry , reductase , genetically modified crops , horticulture , enzyme , botany , gene , biosynthesis
Summary Different transgenic tobacco lines down‐regulated for either one or two enzymes of the monolignol pathway were compared for their lignin content and composition, and developmental patterns. The comparison concerned CCR and CAD down‐regulated lines (homozygous or heterozygous for the transgene) and the hybrids resulting from the crossing of transgenic lines individually altered for CCR or CAD activities. Surprisingly, the crosses containing only one allele of each antisense transgene, exhibit a dramatic reduction of lignin content similar to the CCR down‐regulated parent but, in contrast to this transgenic line, display a normal phenotype and only slight alterations of the shape of the vessels. Qualitatively the lignin of the double transformant displays characteristics more like the wild type control than either of the other transgenics. In the transgenics with a low lignin content, the transformations induced other biochemical changes involving polysaccharides, phenolic components of the cell wall and also soluble phenolics. These results show that the ectopic expression of a specific transgene may have a different impact depending on the genetic background and suggest that the two transgenes present in the crosses may operate synergistically to reduce the lignin content. In addition, these data confirm that plants with a severe reduction in lignin content may undergo normal development at least in controlled conditions.