AUTHOR=Liu Hao , Guo Zhenhua , Gu Fengwei , Ke Shanwen , Sun Dayuan , Dong Shuangyu , Liu Wei , Huang Ming , Xiao Wuming , Yang Guili , Liu Yongzhu , Guo Tao , Wang Hui , Wang Jiafeng , Chen Zhiqiang 

TITLE=4-Coumarate-CoA Ligase-Like Gene OsAAE3 Negatively Mediates the Rice Blast Resistance, Floret Development and Lignin Biosynthesis

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.02041

DOI=10.3389/fpls.2016.02041

ISSN=1664-462X

ABSTRACT=<p>Although adenosine monophosphate (AMP) binding domain is widely distributed in multiple plant species, detailed molecular functions of AMP binding proteins (AMPBPs) in plant development and plant-pathogen interaction remain unclear. In the present study, we identified an AMPBP <italic>OsAAE3</italic> from a previous analysis of early responsive genes in rice during <italic>Magnaporthe oryzae</italic> infection. <italic>OsAAE3</italic> is a homolog of Arabidopsis <italic>AAE3</italic> in rice, which encodes a 4-coumarate-Co-A ligase (4CL) like protein. A phylogenetic analysis showed that <italic>OsAAE3</italic> was most likely <italic>4CL-like 10</italic> in an independent group. <italic>OsAAE3</italic> was localized to cytoplasm, and it could be expressed in various tissues. Histochemical staining of transgenic plants carrying <italic>OsAAE3</italic> promoter-driven GUS (β-glucuronidase) reporter gene suggested that <italic>OsAAE3</italic> was expressed in all tissues of rice. Furthermore, <italic>OsAAE3-OX</italic> plants showed increased susceptibility to <italic>M. Oryzae</italic>, and this finding was attributable to decreased expression of pathogen-related 1a (<italic>PR1</italic>) and low level of peroxidase (POD) activity. Moreover, <italic>OsAAE3</italic> over-expression resulted in increased content of H<sub>2</sub>O<sub>2</sub>, leading to programmed cell-death induced by reactive oxygen species (ROS). In addition, <italic>OsAAE3</italic> over-expression repressed the floret development, exhibiting dramatically twisted glume and decreased fertility rate of anther. Meanwhile, the expressions of lignin biosynthesis genes were significantly decreased in <italic>OsAAE3-OX</italic> plants, thereby leading to reduced lignin content. Taken together, <italic>OsAAE3</italic> functioned as a negative regulator in rice blast resistance, floret development, and lignin biosynthesis. Our findings further expanded the knowledge in functions of AMBPs in plant floret development and the regulation of rice-fungus interaction.</p>