AUTHOR=Jibran Rubina , Tahir Jibran , Cooney Janine , Hunter Donald A. , Dijkwel Paul P. 

TITLE=Arabidopsis AGAMOUS Regulates Sepal Senescence by Driving Jasmonate Production

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.02101

DOI=10.3389/fpls.2017.02101

ISSN=1664-462X

ABSTRACT=<p>The signal that initiates the age-regulated senescence program in flowers is still unknown. Here we propose for the ephemeral <italic>Arabidopsis thaliana</italic> flower that it dies because of continued expression of the MADS-box transcription factor AGAMOUS (AG). AG is necessary for specifying the reproductive structures of the flower. Flowers of <italic>ag-1</italic>, which lack AG, exhibited delayed sepal senescence and abscission. The flowers also had reduced jasmonic acid (JA) content. Other anther-defective sterile mutants deficient in JA, <italic>defective in anther dehiscence 1</italic> (<italic>dad1</italic>) and <italic>delayed dehiscence 2</italic> (<italic>dde2</italic>), exhibited delayed sepal senescence and abscission as well. Manually pollinated <italic>dad1</italic> flowers produced siliques but still had delayed senescence, demonstrating that absence of pollination does not cause delayed senescence. When <italic>ag-1, dad1</italic> and <italic>dde2</italic> flowers were sprayed with 100 μM methyl jasmonate, the sepal senescence and abscission phenotypes were rescued, suggesting that JA has a role in these processes. Our study uncovers a novel role for AG in determining the timing of death of the flower it helps develop and highlights a role for JA in sepal senescence.</p>