Apospory appears to accelerate onset of meiosis and sexual embryo sac formation in sorghum ovules

BMC Plant Biology

Research Article

Michelle Jamison¹  Krishna K Dwivedi¹  Estella Elliott²  Tamara N Naumova³  John G Carman⁴ 

[1] Caisson Laboratories, Inc., 84322-4820, North Logan, Utah, USA;Caisson Laboratories, Inc., 84322-4820, North Logan, Utah, USA;College of Southern Idaho, 1238, Shields Building, 83303, Twin Falls, Idaho, USA;Caisson Laboratories, Inc., 84322-4820, North Logan, Utah, USA;Nalichnaja Street 14 ap. 59, 199406, St. Petersburg, Russia;Plants, Soils & Climate Department, Utah State University, 84322-4820, Logan, Utah, USA;

关键词: Ovule Development;    Ovule Area;    Nucellar Cell;    Apomictic Plant;    Functional Megaspore;   

DOI  :  10.1186/1471-2229-11-9

 received in 2010-10-01, accepted in 2011-01-11,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundGenetically unreduced (2n) embryo sacs (ES) form in ovules of gametophytic apomicts, the 2n eggs of which develop into embryos parthenogenetically. In many apomicts, 2n ES form precociously during ovule development. Whether meiosis and sexual ES formation also occur precociously in facultative apomicts (capable of apomictic and sexual reproduction) has not been studied. We determined onset timing of meiosis and sexual ES formation for 569 Sorghum bicolor genotypes, many of which produced 2n ES facultatively.ResultsGenotype differences for onset timing of meiosis and sexual ES formation, relative to ovule development, were highly significant. A major source of variation in timing of sexual germline development was presence or absence of apomictic ES, which formed from nucellar cells (apospory) in some genotypes. Genotypes that produced these aposporous ES underwent meiosis and sexual ES formation precociously. Aposporous ES formation was most prevalent in subsp. verticilliflorum and in breeding lines of subsp. bicolor. It was uncommon in land races.ConclusionsThe present study adds meiosis and sexual ES formation to floral induction, apomictic ES formation, and parthenogenesis as processes observed to occur precociously in apomictic plants. The temporally diverse nature of these events suggests that an epigenetic memory of the plants' apomixis status exists throughout its life cycle, which triggers, during multiple life cycle phases, temporally distinct processes that accelerate reproduction.

【 授权许可】

CC BY   
© Carman et al; licensee BioMed Central Ltd. 2011