A CYC/TB1-type TCP transcription factor controls spikelet meristem identity in barley.

Yi Shang, Lu Yuan, Zhaocan Di, Yong Jia, Zhenlan Zhang, Sujuan Li, Liping Xing, Zengjun Qi, Xiaoyun Wang, Jinghuan Zhu, Wei Hua, Xiaojian Wu, Minqiu Zhu, Gang Li, Chengdao Li

Journal of experimental botany 2020 Dec 31

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Barley possesses a branchless, spike-shaped inflorescence where determinate spikelets attach directly to the main axis, but the developmental mechanism of spikelet identity remains largely unknown. Here we report the functional analysis of the barley gene BRANCHED AND INDETERMINATE SPIKELET 1 (BDI1), which encodes a TCP transcription factor and plays a crucial role in determining barley inflorescence architecture and spikelet development. The bdi1 mutant exhibited indeterminate spikelet meristems that continued to grow and differentiate after producing a floret meristem; some spikelet meristems at the base of the spike formed two fully developed seeds or converted to branched spikelets, producing a branched inflorescence. Map-based cloning analysis showed that this mutant has a deletion of ~600 kb on chromosome 5H containing three putative genes. Expression analysis and virus-induced gene silencing confirmed that the causative gene, BDI1, encodes a CYC/TB1-type TCP transcription factor and is highly conserved in both wild and cultivated barley. Transcriptome and regulatory network analysis demonstrated that BDI1 may integrate regulation of gene transcription cell wall modification and known trehalose-6-phosphate homeostasis to control spikelet development. Together, our findings reveal that BDI1 represents a key regulator of inflorescence architecture and meristem determinacy in cereal crop plants. © The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Citation

Yi Shang, Lu Yuan, Zhaocan Di, Yong Jia, Zhenlan Zhang, Sujuan Li, Liping Xing, Zengjun Qi, Xiaoyun Wang, Jinghuan Zhu, Wei Hua, Xiaojian Wu, Minqiu Zhu, Gang Li, Chengdao Li. A CYC/TB1-type TCP transcription factor controls spikelet meristem identity in barley. Journal of experimental botany. 2020 Dec 31;71(22):7118-7131