Down-regulation of MeMYB2 leads to anthocyanin accumulation and increases chilling tolerance in cassava (Manihot esculenta Crantz)
Xin Guo,
Xiaohui Yu,
Chenyu Lin,
Pingjuan Zhao,
Bin Wang,
Liangping Zou,
Shuxia Li,
Xiaoling Yu,
Yinhua Chen,
Peng Zhang,
Ming Peng,
Mengbin Ruan
Affiliations
Xin Guo
College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China; National Key Laboratory for Tropical Crop Breeding, Sanya 572025, Hainan, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, Hainan, China; Key Laboratory for Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, Hainan, China
Xiaohui Yu
College of Tropical Crops, Hainan University, Haikou 570228, Hainan, China
Chenyu Lin
College of Tropical Crops, Hainan University, Haikou 570228, Hainan, China
Pingjuan Zhao
Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, Hainan, China; Key Laboratory for Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, Hainan, China
Bin Wang
Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, Hainan, China; Key Laboratory for Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, Hainan, China
Liangping Zou
Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, Hainan, China; Key Laboratory for Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, Hainan, China
Shuxia Li
National Key Laboratory for Tropical Crop Breeding, Sanya 572025, Hainan, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, Hainan, China; Key Laboratory for Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, Hainan, China; Sanya Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572025, Hainan, China
Xiaoling Yu
National Key Laboratory for Tropical Crop Breeding, Sanya 572025, Hainan, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, Hainan, China
Yinhua Chen
College of Tropical Crops, Hainan University, Haikou 570228, Hainan, China
Peng Zhang
National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
Ming Peng
National Key Laboratory for Tropical Crop Breeding, Sanya 572025, Hainan, China; Sanya Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572025, Hainan, China; Corresponding authors.
Mengbin Ruan
National Key Laboratory for Tropical Crop Breeding, Sanya 572025, Hainan, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, Hainan, China; Key Laboratory for Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou 571101, Hainan, China; Sanya Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572025, Hainan, China; Corresponding authors.
Chilling-induced accumulation of reactive oxygen species (ROS) is harmful to plants, which usually produce anthocyanins to scavenge ROS as protection from chilling stress. As a tropical crop, cassava is hypersensitive to chilling, but the biochemical basis of this hypersensitivity remains unclear. We previously generated MeMYB2-RNAi transgenic cassava with increased chilling tolerance. Here we report that MeMYB2-RNAi transgenic cassava accumulated less ROS but more cyanidin-3-O-glucoside than the wild type under early chilling stress. Under this stress, the anthocyanin biosynthesis pathway was more active in MeMYB2-RNAi lines than in the wild type, and several genes involved in the pathway, including MeTT8, were up-regulated by MeMYB2-RNAi in the transgenic cassava. MeMYB2 bound to the MeTT8 promoter and blocked its expression under both normal and chilling conditions, thereby inhibiting anthocyanin accumulation. MeTT8 was shown to bind to the promoter of Dihydroflavonol 4-reductase (MeDFR-2) and increased MeDFR-2 expression. MeMYB2 appears to act as an inhibitor of chilling-induced anthocyanin accumulation during the rapid response of cassava to chilling stress.
