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Silencing of the chalcone synthase gene in C asuarina glauca highlights the important role of flavonoids during nodulation
Author(s) -
AbdelLateif Khalid,
Vaissayre Virginie,
Gherbi Hassen,
Verries Clotilde,
Meudec Emmanuelle,
PerrineWalker Francine,
Cheynier Véronique,
Svistoonoff Sergio,
Franche Claudine,
Bogusz Didier,
Hocher Valérie
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12326
Subject(s) - chalcone synthase , biology , rhizobia , actinorhizal plant , botany , fabaceae , symbiosis , flavonoid biosynthesis , flavonoid , root nodule , biochemistry , transcriptome , gene , gene expression , genetics , bacteria , antioxidant
Summary Nitrogen‐fixing root nodulation is confined to four plant orders, including > 14 000 L eguminosae, one nonlegume genus P arasponia and c . 200 actinorhizal species that form symbioses with rhizobia and F rankia bacterial species, respectively. Flavonoids have been identified as plant signals and developmental regulators for nodulation in legumes and have long been hypothesized to play a critical role during actinorhizal nodulation. However, direct evidence of their involvement in actinorhizal symbiosis is lacking. Here, we used RNA interference to silence chalcone synthase, which is involved in the first committed step of the flavonoid biosynthetic pathway, in the actinorhizal tropical tree C asuarina glauca . Transformed flavonoid‐deficient hairy roots were generated and used to study flavonoid accumulation and further nodulation. Knockdown of chalcone synthase expression reduced the level of specific flavonoids and resulted in severely impaired nodulation. Nodule formation was rescued by supplementing the plants with naringenin, which is an upstream intermediate in flavonoid biosynthesis. Our results provide, for the first time, direct evidence of an important role for flavonoids during the early stages of actinorhizal nodulation.