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The transcription factor MYB115 contributes to the regulation of proanthocyanidin biosynthesis and enhances fungal resistance in poplar
Author(s) -
Wang Lijun,
Ran Lingyu,
Hou Yisu,
Tian Qiaoyan,
Li Chaofeng,
Liu Rui,
Fan Di,
Luo Keming
Publication year - 2017
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.14569
Subject(s) - myb , mutant , arabidopsis , biology , transcription factor , gene , proanthocyanidin , transgene , genetically modified crops , wild type , flavonoid biosynthesis , gene expression , promoter , biosynthesis , biochemistry , transcriptome , polyphenol , antioxidant
Summary Proanthocyanidins ( PA s) are major defense phenolic compounds in the leaves of poplar ( Populus spp.) in response to abiotic and biotic stresses. Transcriptional regulation of PA biosynthetic genes by the MYB‐basic helix–loop–helix (bHLH)‐WD40 complexes in poplar is not still fully understood. Here, an Arabidopsis TT2‐like gene MYB115 was isolated from Populus tomentosa and characterized by various molecular, genetic and biochemical approaches. MYB115 restored PA productions in the seed coat of the Arabidopsis tt2 mutant. Overexpression of MYB115 in poplar activated expression of PA biosynthetic genes, resulting in a significant increase in PA concentrations. By contrast, the CRISPR /Cas9‐generated myb115 mutant exhibited reduced PA content and decreased expression of PA biosynthetic genes. MYB 115 directly activated the promoters of PA ‐specific structural genes. MYB 115 interacted with poplar TT 8. Coexpression of MYB 115 , TT 8 and poplar TTG 1 significantly enhanced the expression of ANR 1 and LAR 3 . Additionally, transgenic plants overexpressing MYB 115 had increased resistance to the fungal pathogen Dothiorella gregaria , whereas myb115 mutant exhibited greater sensitivity compared with wild‐type plants. Our data provide insight into the regulatory mechanisms controlling PA biosynthesis by MYB 115 in poplar, which could be effectively employed for metabolic engineering of PA s to improve resistance to fungal pathogens.