Comparative transcriptome analysis of oil palm flowers reveals an EAR-motif-containing R2R3-MYB that modulates phenylpropene biosynthesis

BMC Plant Biology

Research Article

Nam-Hai Chua¹  Chin Huat Lim²  Genhua Yue³  Rajani Sarojam³  Jingjing Jin³  Vaishnavi Amarr Reddy⁴  Qian Wang⁵  Ran Li⁶  Chakaravarthy Rajan⁷  Jian Ye⁸ 

[1] Laboratory of Plant Molecular Biology, Rockefeller University, 10065, New York, NY, USA;R&D Department, Wilmar International Plantation, Palembang, Indonesia;Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore, Singapore;Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore, Singapore;Department of Biological Sciences, National University of Singapore, 117543, Singapore, Singapore;Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore, Singapore;Present Address: College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, Zhejiang, China;Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore, Singapore;Present Address: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, 07745, Jena, Germany;Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore, Singapore;Present Address: Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore;Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore, Singapore;State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, China;

关键词: MYB transcription factor;    Phenylpropene;    Lignin;    Oil palm;    Basil;    Phenylpropanoid pathway;   

DOI  :  10.1186/s12870-017-1174-4

 received in 2017-05-24, accepted in 2017-11-13,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundOil palm is the most productive oil crop and the efficiency of pollination has a direct impact on the yield of oil. Pollination by wind can occur but maximal pollination is mediated by the weevil E. kamerunicus. These weevils complete their life cycle by feeding on male flowers. Attraction of weevils to oil palm flowers is due to the emission of methylchavicol by both male and female flowers. In search for male flowers, the weevils visit female flowers by accident due to methylchavicol fragrance and deposit pollen. Given the importance of methylchavicol emission on pollination, we performed comparative transcriptome analysis of oil palm flowers and leaves to identify candidate genes involved in methylchavicol production in flowers.ResultsRNA sequencing (RNA-Seq) of male open flowers, female open flowers and leaves was performed using Illumina HiSeq 2000 platform. Analysis of the transcriptome data revealed that the transcripts of methylchavicol biosynthesis genes were strongly up-regulated whereas transcripts encoding genes involved in lignin production such as, caffeic acid O-methyltransferase (COMT) and Ferulate-5-hydroxylase (F5H) were found to be suppressed in oil palm flowers. Among the transcripts encoding transcription factors, an EAR-motif-containing R2R3-MYB transcription factor (EgMYB4) was found to be enriched in oil palm flowers. We determined that EgMYB4 can suppress the expression of a monolignol pathway gene, EgCOMT, in vivo by binding to the AC elements present in the promoter region. EgMYB4 was further functionally characterized in sweet basil which also produces phenylpropenes like oil palm. Transgenic sweet basil plants showed significant reduction in lignin content but produced more phenylpropenes.ConclusionsOur results suggest that EgMYB4 possibly restrains lignin biosynthesis in oil palm flowers thus allowing enhanced carbon flux into the phenylpropene pathway. This study augments our understanding of the diverse roles that EAR-motif-containing MYBs play to fine tune the metabolic flux along the various branches of core phenylpropanoid pathway. This will aid in metabolic engineering of plant aromatic compounds.

【 授权许可】

CC BY   
© The Author(s). 2017