Os03g0782500

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Annotated Information

Function

This gene encodes a phytochrome-interacting factor-like protein named OsPIL1/OsPIL13. It acts as a key regulator of reduced internode elongation in rice under drought conditions. OsPIL1 downstream genes, which were enriched for cell wall-related genes responsible for cell elongation. OsPIL1 functions as a key regulatory factor of reduced plant height via cell wall-related genes in response to drought stress. This regulatory system may be important for morphological stress adaptation in rice under drought conditions.

Expression

The level of OsPIL1 mRNA in rice seedlings grown under nonstressed conditions with light/dark cycles oscillated in a circadian manner with peaks in the middle of the light period. Under drought stress conditions, OsPIL1 expression was inhibited during the light period. OsPIL1 was highly expressed in the node portions of the stem using promoter-glucuronidase analysis. Overexpression of OsPIL1 in transgenic rice plants promoted internode elongation. In contrast, transgenic rice plants with a chimeric repressor resulted in short internode sections.

A rice PIF-like gene (OsPIL1/OsPIL13, LOC_Os03g56950) was identified by microarray analyses as one of the stress-responsive transcription factor genes that were down-regulated by drought stress. First, we confirmed the stress-responsive expression pattern of the OsPIL1 gene. The level of OsPIL1 mRNA in rice seedlings grown under nonstressed conditions with 12-h light/12-h dark cycles oscillated in a circadianmanner, with peaks in the middle of the light period.

Evolution

The molecular mechanisms for the regulation of plant growth and development during stress conditions remains unclear. Our data provide evidence that OsPIL1 functions as a key regulator of reduced plant height in rice during stress conditions. Several results support this conclusion: (i) OsPIL1-OXs showed activated internode elongation via increased cell size, whereas OsPIL1-RDs had short internode sections resulting from decreased cell size; (ii) OsPIL1 downstream genes included a number of the cell wall-related genes, which have been reported to be involved in plant growth regulation by cell elongation; and (iii) light-dependent expression of OsPIL1 was clearly inhibited during stress conditions. The set of down-regulated genes in OsPIL1-OXs included many drought-inducible genes in rice plants. We compared these down-regulated genes with genes downstream of the transcription factors OsDREB1A, OsNAC6, and OsbZIP23, which have been reported to positively regulate expression of stress-responsive genes in rice plants. The number of genes downstream of OsDREB1A, OsNAC6, and OsbZIP23 was 81, 158, and 743, respectively (38–40). Among these genes, only 13, 37, and 61 genes overlapped with the down-regulated genes in OsPIL1-OXs, respectively. These results suggest that the pathways regulated by OsDREB1A, OsNAC6 and OsbZIP23 act in parallel to the pathway regulated by OsPIL1.

Labs working on this gene

Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan;

Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan

Gene Function Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8562, Japan

Plant Productivity Systems Research Group and Gene Discovery Research Group, RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan

References

1. Daisuke Todaka;Kazuo Nakashima;Kyonoshin Maruyama;Satoshi Kidokoro;Yuriko Osakabe;Yusuke Ito;Satoko Matsukura;Yasunari Fujita;Kyouko Yoshiwara;Masaru Ohme-Takagi;Mikiko Kojima;Hitoshi Sakakibara;Kazuo Shinozakie;Kazuko Yamaguchi-Shinozaki.Rice phytochrome-interacting factor-like protein OsPIL1 functions as a key regulator of internode elongation and induces a morphological response to drought stress.Proceedings of the National Academy of Sciences, 2012, 109(39): 15947-15952

2. Xiao-Ling Zhao;Zhen-Ying Shi;Ling-Tao Peng;Ge-Zhi Shen;Jing-Liu Zhang.An atypical HLH protein OsLF in rice regulates flowering time and interacts with OsPIL13 and OsPIL15.New Biotechnology, 2011, 28(6): 788-797

3. Yuko NAKAMURA;Takahiko KATO;Takafumi YAMASHINO;Masaya MURAKAMI;Takeshi MIZUNO.Characterization of a Set of Phytochrome-Interacting Factor-Like bHLH Proteins in Oryza sativa.Bioscience, Biotechnology, and Biochemistry, 2007, 71(5): 1183-1191