Document Detail


Sexual reproduction is the default mode in apomictic Hieracium subgenus Pilosella where two dominant loci function to enable apomixis.
MedLine Citation:
PMID:  21418351     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Asexual seed formation, or apomixis, in Hieracium subgenus Pilosella is controlled by two dominant, independent genetic loci, LOSS OF APOMEIOSIS (LOA) and LOSS OF PARTHENOGENESIS (LOP). We examined apomixis mutants that had lost function in one or both loci to establish their developmental roles during seed formation. In apomicts, sexual reproduction initiates first. Somatic aposporous initial (AI) cells differentiate near meiotic cells and the sexual pathway is terminated as AI cells undergo mitotic embryo sac formation. Seed initiation is fertilization-independent. Using a partially-penetrant cytotoxic reporter to inhibit meioisis we showed that the developmental events leading to the completion of meiotic tetrad formation are required for AI cell formation. Sex may therefore stimulate activity of the LOA locus which we found is required for AI formation and subsequent suppression of the sexual pathway. AI cells undergo nuclear division to form embryo sacs where LOP functions gametophytically to stimulate fertilization-independent embryo and endosperm formation. Loss of function in either locus results in partial reversion to sexual reproduction and loss of function in both loci results in reversion to sexual reproduction. Therefore, in these apomicts, sex is the default reproductive mode upon which apomixis is superimposed. These loci are unlikely to encode genes essential for sexual reproduction but may function to recruit the sexual machinery at specific time points to enable apomixis.
Authors:
Anna M G Koltunow; Susan D Johnson; Julio C M Rodrigues; Takashi Okada; Yingkao Hu; Tohru Tsuchiya; Saira Wilson; Pam Fletcher; Kanae Ito; Go Suzuki; Yasuhiko Mukai; Judith Fehrer; Ross A Bicknell
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-3-21
Journal Detail:
Title:  The Plant journal : for cell and molecular biology     Volume:  -     ISSN:  1365-313X     ISO Abbreviation:  -     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-3-22     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9207397     Medline TA:  Plant J     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011 Blackwell Publishing Ltd and the Society for Experimental Biology.
Affiliation:
Commonwealth Scientific and Industrial Research Organization Plant Industry, Glen Osmond, South Australia 5064, Australia. Present address, Embrapa Genetic Research and Biotechnology, 70770-900 Brasilia, Brazil. College of Life Science, Capital Normal University, Xi San Huan Bei Lu 105, Beijing, 100037, China. Life Science Research Center, Mie University, 1577 Kurima-machiya, Tsu 514-8507, Japan. Plant and Food Research Ltd., Private Bag 4704, Christchurch Mail Centre, Christchurch 8140, New Zealand. Laboratory of Plant Molecular Genetics Division of Natural Science, Osaka Kyoiku University 4-698-1 Asahigaoka, Kashiwara, Osaka 582-8582, Japan Institute of Botany, Czech Academy of Sciences, Zámek 1, 25243 Průhonice, Czech Republic.
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