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Chinese Scientists Reveal a New Mechanism of Plant Architecture Development

Source: Institute of Vegetables and Flowers

On July 13, Nature Plants published the latest research results on gene expression regulation of plant architecture development, which were jointly studied by 6 institutions including Insititute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Shenzhen Institute of Agricultural Genomics, Institute of Biophysics of Chinese Academy of Sciences, and University of California, Davis. This study discovered the molecular mechanism of the cucumber tendril identity gene TEN, a transcription factor of the TCP family, regulating tendrils development and mobility in cucumber, revealed how intragenic binding by a transcription factor regulated gene expression, and provided an important breakthrough for understanding the gene regulatory network of plant architecture development.

 

In protected cultivation, cucumbers grow on manual support, so tendrils are dispensable and tendril development also increases competition for nutrients. So it should be removed in time to promote healthy growth of cucumber fruit. However, it is time-consuming and laborious to remove tendrils manually. Therefore, cultivating varieties without tendrils, suitable for the simplified cultivation, has become an important direction for the improvement of cucumber plant architecture. Previous research by the team cloned the identity gene TEN, which controls tendrils' development, and revealed that the cucumber tendrils' homologous organs are lateral branches.

 

TEN belongs to the CYC/TB1 transcription factor of the TCP family. Through the study of the molecular mechanism of TEN regulating the morphological development and mobility of the tendrils, the authors discovered that TEN directly regulates the synthesis of ethylene to control the morphology and climbing of the tendrils. The team found that TEN is a new type of multifunctional transcription factor, its C-terminus is responsible for binding at intragenic enhancers of target genes, and its N-terminus domain functions as a non-canonical histone acetyltransferase, which mainly acetylates the histone H3 globular domain, responsible for chromatin loosing, thereby activating target gene expression. CYC / TB1 transcription factors have central roles in controlling crop plant architecture. For example, the major domestication gene TB1 suppresses branch outgrowth , and promotes the transition of teosinte to corn.

 

The team discovered that the homologous gene TB1 of TEN in corn activates gene expression through the same mechanism that binds to the intragenic enhancer of target genes, thereby revealing a new mechanism for the conservative expression and regulation of CYC/TB1 transcription factors. The team further analyzed the genome-wide binding data of enhancer-binding transcription factors-HSF-1 and ERα in humans, and speculated that in eukaryotes, the acetylation of the histone globular domain may be a conservative mechanism for the regulation of intragenic enhancer expression . This research reveals the basic scientific problem of how intragenic binding by a transcription factor can regulate gene expression. It is also of great significance for understanding its function in the development of axillary buds and applying it to crop plant architecture improvement, and can be directly used in the simplified cultivation.

 

This research is the collaborative innovation achievements by innovation team of Yang Xueyong of Institute of Vegetables and Flowers and teams of Yan Jianbin and Huang Sanwen of Agricultural Genomic Institute at Shenzhen. It was supported by national Key Natural Science Foundation of China, General Project of National Natural Science Foundation of China, national Key RESEARCH and development Plan and other projects.

 

More details can be found at the link below:

http://www.nature.com/articles/s41477-020-0715-2

 

By Yang Xueyong (yangxueyong@caas.cn)