SHORT INTERNODES-like genes regulate shoot growth and xylem proliferation in Populus
Christine Zawaski1, Mahita Kadmiel2, Cathleen Ma3
1School of Forest Research and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA.
The New Phytologist
|May 14, 2011
Summary
Researchers identified poplar SHORT INTERNODES-RELATED SEQUENCE (SRS) genes regulating plant growth. Manipulating these genes altered growth, wood formation, and hormone levels, offering potential for improving biomass and wood quality.
Area of Science:
- Plant Biology
- Genetics
- Molecular Biology
Background:
- Genes controlling plant growth and form are crucial for survival and productivity but are often poorly understood.
- The SHORT INTERNODES (SHI) gene, part of the SHI-RELATED SEQUENCE (SRS) family, is a key developmental regulator in Arabidopsis.
Purpose of the Study:
- To identify and characterize poplar SRS genes homologous to Arabidopsis SHI and STY1.
- To investigate the role of these poplar SRS genes in regulating plant vegetative growth and wood formation.
Main Methods:
- Comparative sequence analysis of SRS gene families in poplar and Arabidopsis.
- RNA interference (RNAi) to suppress poplar SRS gene function.
- Overexpression of Arabidopsis SHI in poplar.
- Analysis of plant growth, fiber length, xylem formation, and plant hormone levels (gibberellins, cytokinin).
Main Results:
- Two poplar genes, highly similar to Arabidopsis SHI and STY1, were identified as likely paralogs with redundant functions.
- RNAi suppression of these poplar genes led to enhanced shoot and root growth.
- Overexpression of Arabidopsis SHI reduced internode and petiole length in poplar.
- Suppression of poplar SRS genes increased fiber length and xylem proportion via increased cell proliferation, altering gibberellin and cytokinin levels.
Conclusions:
- Populus SRS genes are significant regulators of vegetative growth, including wood formation.
- These genes represent valuable tools for modifying biomass productivity, wood quality, and plant architecture.
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