AUTHOR=Ding Jinjin , Karim Hassan , Li Yulong , Harwood Wendy , Guzmán Carlos , Lin Na , Xu Qiang , Zhang Yazhou , Tang Huaping , Jiang Yunfeng , Qi Pengfei , Deng Mei , Ma Jian , Wang Jirui , Chen Guoyue , Lan Xiujin , Wei Yuming , Zheng Youliang , Jiang Qiantao 

TITLE=Re-examination of the APETALA2/Ethylene-Responsive Factor Gene Family in Barley (Hordeum vulgare L.) Indicates a Role in the Regulation of Starch Synthesis

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.791584

DOI=10.3389/fpls.2021.791584

ISSN=1664-462X

ABSTRACT=<p>The <italic>APETALA2/Ethylene-Responsive</italic> factor (<italic>AP2/ERF</italic>) gene family is a large plant-specific transcription factor family, which plays important roles in regulating plant growth and development. A role in starch synthesis is among the multiple functions of this family of transcription factors. Barley (<italic>Hordeum vulgare</italic> L.) is one of the most important cereals for starch production. However, there are limited data on the contribution of AP2 transcription factors in barley. In this study, we used the recently published barley genome database (Morex) to identify 185 genes of the <italic>HvAP2/ERF</italic> family. Compared with previous work, we identified 64 new genes in the <italic>HvAP2/ERF</italic> gene family and corrected some previously misannotated and duplicated genes. After phylogenetic analysis, <italic>HvAP2/ERF</italic> genes were classified into four subfamilies and 18 subgroups. Expression profiling showed different patterns of spatial and temporal expression for <italic>HvAP2/ERF</italic> genes. Most of the 12 <italic>HvAP2/ERF</italic> genes analyzed using quantitative reverse transcription–polymerase chain reaction had similar expression patterns when compared with those of starch synthase genes in barley, except for <italic>HvAP2-18</italic> and <italic>HvERF-73</italic>. <italic>HvAP2-18</italic> is homologous to <italic>OsRSR1</italic>, which negatively regulates the synthesis of rice starch. Luciferase reporter gene, and yeast one-hybrid assays showed that <italic>HvAP2-18</italic> bound the promoter of <italic>AGP-S</italic> and <italic>SBE1 in vitro</italic>. Thus, <italic>HvAP2-18</italic> might be an interesting candidate gene to further explore the mechanisms involved in the regulation of starch synthesis in barley.</p>