AUTHOR=Yang Xue , Zhang Yuntong , Shan Jinming , Sun Jingzhe , Li Dongmei , Zhang Xiaoming , Li Wenbin , Zhao Lin 

TITLE=GmIDD Is Induced by Short Days in Soybean and May Accelerate Flowering When Overexpressed in Arabidopsis via Inhibiting AGAMOUS-LIKE 18

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.629069

DOI=10.3389/fpls.2021.629069

ISSN=1664-462X

ABSTRACT=<p>Photoperiod is one of the main climatic factors that determine flowering time and yield. Some members of the INDETERMINATE DOMAIN (IDD) transcription factor family have been reported to be involved in regulation of flowering time in Arabidopsis, maize, and rice. In this study, the domain analysis showed that GmIDD had a typical ID domain and was a member of the soybean IDD transcription factor family. Quantitative real-time PCR analysis showed that <italic>GmIDD</italic> was induced by short day conditions in leaves and regulated by circadian clock. Under long day conditions, transgenic Arabidopsis overexpressing <italic>GmIDD</italic> flowered earlier than wild-type, and <italic>idd</italic> mutants flowered later, while the overexpression of <italic>GmIDD</italic> rescued the late-flowering phenotype of <italic>idd</italic> mutants. Chromatin immunoprecipitation sequencing assays of <italic>GmIDD</italic> binding sites in <italic>GmIDD-overexpression (GmIDD-ox)</italic> Arabidopsis further identified potential direct targets, including a transcription factor, <italic>AGAMOUS-like 18</italic> (<italic>AGL18</italic>). <italic>GmIDD</italic> might inhibit the transcriptional activity of flower repressor <italic>AGL18</italic> by binding to the <italic>TTTTGGTCC</italic> motif of <italic>AGL18</italic> promoter. Furthermore, the results also showed that <italic>GmIDD</italic> overexpression increased the transcription levels of flowering time-related genes <italic>FLOWERING LOCUS T</italic> (<italic>FT</italic>), <italic>SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1</italic> (<italic>SOC1</italic>), <italic>LEAFY</italic> (<italic>LFY</italic>) and <italic>APETALA1</italic> (<italic>AP1</italic>) in Arabidopsis. Taken together, <italic>GmIDD</italic> appeared to inhibit the transcriptional activity of <italic>AGL18</italic> and induced the expression of <italic>FT</italic> gene to promote Arabidopsis flowering.</p>