AUTHOR=Liu Mengjia , Li Haifeng , Su Yali , Li Wenqiang , Shi Chunhai 

TITLE=G1/ELE Functions in the Development of Rice Lemmas in Addition to Determining Identities of Empty Glumes

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.01006

DOI=10.3389/fpls.2016.01006

ISSN=1664-462X

ABSTRACT=<p>Rice empty glumes, also named sterile lemmas or rudimentary lemmas according to different interpretations, are distinct from lemmas in morphology and cellular pattern. Consistently, the molecular mechanism to control the development of lemmas is different from that of empty glumes. Rice <italic>LEAFY HULL STERILE1</italic>(<italic>OsLHS1</italic>) and <italic>DROOPING LEAF</italic>(<italic>DL</italic>) regulate the cellular pattern and the number of vascular bundles of lemmas respectively, while <italic>LONG STERILE LEMMA1</italic> (<italic>G1</italic>)/<italic>ELONGATED EMPTY GLUME</italic> (<italic>ELE</italic>) and <italic>PANICLE PHYTOMER2</italic> (<italic>PAP2</italic>)/<italic>OsMADS34</italic> determine identities of empty glumes. Though some progress has been made, identities of empty glumes remain unclear, and genetic interactions between lemma genes and glume genes have been rarely elucidated. In this research, a new <italic>G1/ELE</italic> mutant <italic>g1–6</italic> was identified and the phenotype was analyzed. Similar to previously reported mutant lines of <italic>G1/ELE</italic>, empty glumes of <italic>g1–6</italic> plants transform into lemma-like organs. Furthermore, Phenotypes of single and double mutant plants suggest that, in addition to their previously described gene-specific functions, <italic>G1/ELE</italic> and <italic>OsLHS1</italic> play redundant roles in controlling vascular bundle number, cell volume, and cell layer number of empty glumes and lemmas. Meanwhile, expression patterns of <italic>G1/ELE</italic> in <italic>osmads1-z</italic> flowers and <italic>OsLHS1</italic> in <italic>g1–6</italic> flowers indicate they do not regulate each other at the level of transcription. Finally, down-regulation of the empty glume gene <italic>OsMADS34/PAP2</italic> and ectopic expression of the lemma gene <italic>DL</italic>, in the <italic>g1–6</italic> plants provide further evidence that empty glumes are sterile lemmas. Generally, our findings provided valuable information for better understanding functions of <italic>G1</italic> and <italic>OsLHS1</italic> in flower development and identities of empty glumes.</p>