AUTHOR=Wu Jian , Seng Shanshan , Sui Juanjuan , Vonapartis Eliana , Luo Xian , Gong Benhe , Liu Chen , Wu Chenyu , Liu Chao , Zhang Fengqin , He Junna , Yi Mingfang 

TITLE=Gladiolus hybridus ABSCISIC ACID INSENSITIVE 5 (GhABI5) is an important transcription factor in ABA signaling that can enhance Gladiolus corm dormancy and Arabidopsis seed dormancy.

JOURNAL=Frontiers in Plant Science

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2015.00960

DOI=10.3389/fpls.2015.00960

ISSN=1664-462X

ABSTRACT=<p>The phytohormone abscisic acid (ABA) regulates plant development and is crucial for abiotic stress response. In this study, cold storage contributes to reducing endogenous ABA content, resulting in dormancy breaking of <italic>Gladiolus</italic>. The ABA inhibitor fluridone also promotes germination, suggesting that ABA is an important hormone that regulates corm dormancy. Here, we report the identification and functional characterization of the <italic>Gladiolus</italic> ABI5 homolog (<italic>Gh</italic>ABI5), which is a basic leucine zipper motif transcriptional factor (TF). <italic>Gh</italic>ABI5 is expressed in dormant vegetative organs (corm, cormel, and stolon) as well as in reproductive organs (stamen), and it is up-regulated by ABA or drought. Complementation analysis reveals that <italic>Gh</italic>ABI5 rescues the ABA insensitivity of <italic>abi5-3</italic> during seed germination and induces the expression of downstream ABA response genes in <italic>Arabidopsis thaliana</italic> (<italic>EM1</italic>, <italic>EM6</italic>, and <italic>RD29B</italic>). Down-regulation of <italic>GhABI5</italic> in dormant cormels via virus induced gene silence promotes sprouting and reduces the expression of downstream genes (<italic>GhLEA</italic> and <italic>GhRD29B</italic>). The results of this study reveal that <italic>Gh</italic>ABI5 regulates bud dormancy (vegetative organ) in <italic>Gladiolus</italic> in addition to its well-studied function in <italic>Arabidopsis</italic> seeds (reproductive organ).</p>