Asexual Female Gametogenesis Involves Contact with a Sexually-Fated Megaspore in Apomictic Hieracium
نویسندگان
چکیده
منابع مشابه
Photoperiod Extension Enhances Sexual Megaspore Formation and Triggers Metabolic Reprogramming in Facultative Apomictic Ranunculus auricomus
Meiosis, the key step of sexual reproduction, persists in facultative apomictic plants functional to some extent. However, it still remains unclear how and why proportions of reproductive pathways vary under different environmental stress conditions. We hypothesized that oxidative stress mediates alterations of developmental pathways. In apomictic plants we expected that megasporogenesis, the s...
متن کاملSexual and apomictic reproduction in Hieracium subgenus pilosella are closely interrelated developmental pathways.
Seed formation in flowering plants requires meiosis of the megaspore mother cell (MMC) inside the ovule, selection of a megaspore that undergoes mitosis to form an embryo sac, and double fertilization to initiate embryo and endosperm formation. During apomixis, or asexual seed formation, in Hieracium ovules, a somatic aposporous initial (AI) cell divides to form a structurally variable aposporo...
متن کاملPatterns of plastid and nuclear variation among apomictic polyploids of Hieracium: evolutionary processes and taxonomic implications.
BACKGROUND AND AIMS Apomictic species (with asexual seed production) make up for 20-50 % of all taxonomically recognized species in northern Europe, but the phylogenetic relationships of apomictic species and the mode of evolution and speciation remain largely unknown and their taxonomy is consequently disputed. METHODS In the present study, plastid psbD-trnT sequences (349 accessions) and 12...
متن کاملChromosomes carrying meiotic avoidance loci in three apomictic eudicot Hieracium subgenus Pilosella species share structural features with two monocot apomicts.
The LOSS OF APOMEIOSIS (LOA) locus is one of two dominant loci known to control apomixis in the eudicot Hieracium praealtum. LOA stimulates the differentiation of somatic aposporous initial cells after the initiation of meiosis in ovules. Aposporous initial cells undergo nuclear proliferation close to sexual megaspores, forming unreduced aposporous embryo sacs, and the sexual program ceases. LO...
متن کاملRecovery of a sexual and an apomictic hybrid from crosses between the facultative apomicts Hieracium caespitosum and H. praealtum
Hybridisation is a rare event in facultatively apomictic species. We report the recovery of two hybrids from reciprocal crosses between the facultatively apomictic species Hieracium praealtum and H. caespitosum. Both parents were tetraploid (2n=4x=36). H. caespitosum x H. praealtum (CR6) was a hexaploid (2n=6x=54) and an apomict. The increased ploidy number is evidence of a BIII hybrid origin, ...
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ژورنال
عنوان ژورنال: Plant Physiology
سال: 2018
ISSN: 0032-0889,1532-2548
DOI: 10.1104/pp.18.00342