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Deshpande GM, Ramakrishna K, Chongloi GL, Vijayraghavan U. Functions for rice RFL in vegetative axillary meristem specification and outgrowth. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2773-84. [PMID: 25788736 PMCID: PMC4986878 DOI: 10.1093/jxb/erv092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Axillary meristems (AMs) are secondary shoot meristems whose outgrowth determines plant architecture. In rice, AMs form tillers, and tillering mutants reveal an interplay between transcription factors and the phytohormones auxin and strigolactone as some factors that underpin this developmental process. Previous studies showed that knockdown of the transcription factor gene RFL reduced tillering and caused a very large decrease in panicle branching. Here, the relationship between RFL, AM initiation, and outgrowth was examined. We show that RFL promotes AM specification through its effects on LAX1 and CUC genes, as their expression was modulated on RFL knockdown, on induction of RFL:GR fusion protein, and by a repressive RFL-EAR fusion protein. Further, we report reduced expression of auxin transporter genes OsPIN1 and OsPIN3 in the culm of RFL knockdown transgenic plants. Additionally, subtle change in the spatial pattern of IR4 DR5:GFP auxin reporter was observed, which hints at compromised auxin transport on RFL knockdown. The relationship between RFL, strigolactone signalling, and bud outgrowth was studied by transcript analyses and by the tillering phenotype of transgenic plants knocked down for both RFL and D3. These data suggest indirect RFL-strigolactone links that may affect tillering. Further, we show expression modulation of the auxin transporter gene OsPIN3 upon RFL:GR protein induction and by the repressive RFL-EAR protein. These modified forms of RFL had only indirect effects on OsPIN1. Together, we have found that RFL regulates the LAX1 and CUC genes during AM specification, and positively influences the outgrowth of AMs though its effects on auxin transport.
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Affiliation(s)
- Gauravi M Deshpande
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Kavitha Ramakrishna
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Grace L Chongloi
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Usha Vijayraghavan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
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Katoh A, Ashida H, Kasajima I, Shigeoka S, Yokota A. Potato yield enhancement through intensification of sink and source performances. BREEDING SCIENCE 2015; 65:77-84. [PMID: 25931982 PMCID: PMC4374566 DOI: 10.1270/jsbbs.65.77] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/27/2015] [Indexed: 05/07/2023]
Abstract
The combined total annual yield of six major crops (maize, rice, wheat, cassava, soybean, and potato; Solanum tuberosum L.) amounts to 3.1 billion tons. In recent years, staple crops have begun to be used as substitutes for fossil fuel and feedstocks. The diversion of crop products to fuels and industrial feedstocks has become a concern in many countries because of competition for arable lands and increased food prices. These concerns are definitely justified; however, if plant biotechnology succeeds in increasing crop yields to double the current yields, it will be possible to divert the surplus to purposes other than food without detrimental effects. Maize, rice, wheat, and soybean bear their sink organs in the aerial parts of the plant, and potato in the underground parts. Plants with aerial storage organs cannot accumulate products beyond their capacity to support the weight of these organs. In contrast, potato has heavy storage organs that are supported by the soil. In this mini-review, we introduce strategies of intensifying potato productivity and discuss recent advances in this research area.
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Affiliation(s)
- Akira Katoh
- Center for Frontier Science and Technology, Nara Institute of Science and Technology,
Takayama 8916-5, Ikoma, Nara 630-0192,
Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency,
Kawaguchi, Saitama 332-0012,
Japan
| | - Hiroki Ashida
- Graduate School of Human Development and Environment, Kobe University,
3-11 Tsurukabuto, Nada, Kobe, Hyogo 657-8501,
Japan
| | - Ichiro Kasajima
- Center for Frontier Science and Technology, Nara Institute of Science and Technology,
Takayama 8916-5, Ikoma, Nara 630-0192,
Japan
- Institute of Floricultural Science, National Agriculture and Food Research Organization,
2-1, Fujimoto, Tsukuba, Ibaraki 305-8519,
Japan
| | - Shigeru Shigeoka
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency,
Kawaguchi, Saitama 332-0012,
Japan
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University,
3327-204 Nakamachi, Nara 631-8505,
Japan
| | - Akiho Yokota
- Center for Frontier Science and Technology, Nara Institute of Science and Technology,
Takayama 8916-5, Ikoma, Nara 630-0192,
Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency,
Kawaguchi, Saitama 332-0012,
Japan
- Corresponding author (e-mail: )
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