AUTHOR=Zhang Qian , Hou Congcong , Tian Yudan , Tang Mitianguo , Feng Changxin , Ren Zhijie , Song Jiali , Wang Xiaohan , Li Tiange , Li Mengou , Tian Wang , Qiu Jinlong , Liu Liangyu , Li Legong 

TITLE=Interaction Between AtCML9 and AtMLO10 Regulates Pollen Tube Development and Seed Setting

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.01119

DOI=10.3389/fpls.2020.01119

ISSN=1664-462X

ABSTRACT=<p>In higher-plant reproduction, the compatibility of pollen tube germination in the pistil is essential for successful double fertilization. It has been reported that <italic>Mildew Locus O</italic> (<italic>MLO</italic>) family gene <italic>NTA</italic> (<italic>MLO7</italic>), expressing in synergid cells, can correctly guide pollen tubes. However, the molecular mechanism underlying the interacting partners to MLOs in the fertilization is still unknown. In our study, we identified the direct protein interaction between CML9 and MLO10 within a non-canonical CaMBD. In GUS reporter assays, <italic>CML9</italic> expresses in a high level in pollens, whereas <italic>MLO10</italic> can be specifically detected in stigma which reaches up to a peaking level before fertilization. Therefore, the spatio-temporal expression patterns of <italic>MLO10</italic> and <italic>CML9</italic> are required for the time-window of pollination. When we observed the pollen germination <italic>in vitro</italic>, two <italic>cml9</italic> mutant alleles dramatically reduced germination rate by 15% compared to wild-type. Consistently, the elongation rate of pollen tubes <italic>in planta</italic> was obviously slow while manually pollinating <italic>cml9-1</italic> pollens to <italic>mlo10-1</italic> stigmas. Additionally, <italic>cml9-1 mlo10-1</italic> double mutant alleles had relatively lower rate of seed setting. Taken together, protein interaction between MLO10 and CML9 is supposed to affect pollen tube elongation and further affect seed development.</p>