A homeodomain-leucine zipper I transcription factor, MeHDZ14, regulates internode elongation and leaf rolling in cassava (Manihot esculenta Crantz)
Xiaoling Yu,
Xin Guo,
Pingjuan Zhao,
Shuxia Li,
Liangping Zou,
Wenbin Li,
Ziyin Xu,
Ming Peng,
Mengbin Ruan
Affiliations
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
Xin Guo
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; Sanya Research Institute, Chinese Academy of Tropical Agricultural Sciences, Sanya 572025, 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
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
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
Wenbin Li
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
Ziyin Xu
College of Tropical Crops, Hainan University, Haikou 570228, Hainan, 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
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 author.
Drought stress impairs plant growth and other physiological functions. MeHDZ14, a homeodomain-leucine zipper I transcription factor, is strongly induced by drought stress in various cassava cultivars. However, the role of MeHDZ14 in cassava growth regulation has remained unclear. Here we report that MeHDZ14 affected plant height, such that a dwarf phenotype and altered internode elongation were observed in transgenic cassava lines. MeHDZ14 was found to negatively regulate the biosynthesis of lignin. Its overexpression resulted in abaxially rolled leaves. The morphogenesis of leaf epidermal cells was inhibited by overexpression of MeHDZ14, with decreased auxin and gibberellin and increased cytokinin contents. MeHDZ14 was found to regulate many drought-responsive genes, including genes involved in cell wall synthesis and expansion. MeHDZ14 bound to the promoter of caffeic acid 3-O-methyltransferase 1 (MeCOMT1), acting as a transcriptional repressor of genes involved in cell wall development. MeHDZ14 appears to act as a negative regulator of internode elongation and epidermal cell morphogenesis during cassava leaf development.
