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The ARGONAUTE10 gene modulates shoot apical meristem maintenance and establishment of leaf polarity by repressing miR165/166 in Arabidopsis
Author(s) -
Liu Qili,
Yao Xiaozhen,
Pi Limin,
Wang Hua,
Cui Xiaofeng,
Huang Hai
Publication year - 2009
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2008.03757.x
Subject(s) - meristem , arabidopsis , mutant , biology , gene , polarity (international relations) , microbiology and biotechnology , arabidopsis thaliana , phenotype , homeobox , genetics , botany , transcription factor , cell
Summary The shoot apical meristem (SAM) of angiosperms comprises a group of undifferentiated cells which divide to maintain the meristem and also give rise to all the above‐ground structures of the plant. Previous studies revealed that the Arabidopsis ARGONAUTE10 [ AGO10 , also called PINHEAD ( PNH ) or ZWILLE ( ZLL )] gene is one of the critical SAM regulators, but the mechanism by which AGO10 modulates the SAM is unknown. In the present study we show that AGO10 genetically represses microRNA165/166 (miR165/166) for SAM maintenance as well as establishment of leaf adaxial–abaxial polarity. Levels of miR165/166 in leaves and embryonic SAMs of pnh / zll / ago10 mutants are abnormally elevated, leading to a reduction in the quantity of homeodomain‐leucine zipper (HD‐ZIP) III gene transcripts, the targets of miR165/166. This reduction is the primary cause of pnh / zll SAM and leaf defects, because the aberrant pnh / zll phenotypes were partially rescued by either increasing levels of HD‐ZIP III transcripts or decreasing levels of miR165/166 in the SAM and leaf. Furthermore, plants with an abnormal apex were more frequent among pnh / zll rdr6 and pnh / zll ago7 double mutants and increased levels of miR165/166 were detected in rdr6 apices. These results indicate that AGO10 and RDR6 / AGO7 may act in parallel in modulating accumulation of miR165/166 for normal plant development.