To identify genomic regions that carry genetic factors controlling embryogenic potential of isolated microspores of rapeseed, marker segregations were analysed in a segregating population of haploid microspore-derived embryos and a BC₁ population from a cross between ‘Express 617’ and ‘RS239’.

Laboratório de Sistemática e Tafonomia de Vertebrados Fósseis, Departamento de Geologia e Paleontologia do Museu Nacional/UFRJ, Quinta da Boa Vista, s/n, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brasil. Health Sciences is one of the areas that the Annals of the Brazilian Academy of Sciences (AABC) will be stimulating. The purpose is to get scientists in Brazil and from abroad to submit manuscripts in a greater variety of fields than what we have been currently publishing.

Previous research using a bread wheat RIL population of the Seri/Babax cross showed that common QTL were associated with cooler canopies under both drought and heat-stressed conditions. A subset of RIL was grown under water-limited and hot-irrigated field environments to test how cooler canopies are related to root development. Eight sisters and the two parents were used in the study with genotypes grouped as COOL or HOT according to their respective QTL for canopy temperature and previous phenotypic data.

Meiotic recombination is known to vary over 1,000-fold in many eukaryotic organisms, including maize. This regional genomic variation has enormous consequences for plant breeders, who rely on meiotic cross-overs to fine-map quantitative traits and introgress favorable alleles. Deleterious mutations are also predicted to accumulate preferentially within low-recombination regions, particularly within historically outcrossing species, such as maize.

How organisms respond to environment changes is a fundamental and intriguing question in biology. Light is the energy resource and a crucial environmental cue for plant major developmental switches, such as seed germination. Studying the underlying mechanism is important for us to understand the basic principles of plant development and improve crop productions. Here we identify DET1 as a novel central repressor of seed germination. We further reveal that seeds use a multilevel regulatory circuit of triple feed-forward loops to sensitively and precisely mediate light-regulated germination.

Numerous studies using single nucleotide polymorphisms (SNPs) have been conducted in humans, and other animals, and in major crops, including rice, soybean, and Chinese cabbage. However, the number of SNP studies in cabbage is limited. In this present study, we evaluated whether 7,645 SNPs previously identified as molecular markers linked to disease resistance in the Brassica rapa genome could be applied to B. oleracea.

Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is the most devastating pathogen of soybean. Many gene expression profiling studies have been conducted to investigate the responses of soybean to the infection by this pathogen using primarily the first-generation soybean genome array that covered approximately 37,500 soybean transcripts.

DNA methylation is critical for transposon silencing and gene regulation. DNA methylation levels are determined by the combined activities of DNA methyltransferases and demethylases. This study found a 39-bp DNA methylation monitoring sequence (MEMS) in the promoter of the DNA demethylase REPRESSOR OF SILENCING 1 (ROS1) gene of Arabidopsis plants. DNA methylation of MEMS is responsive to both RNA-directed DNA methylation and ROS1-dependent active demethylation.

The present work extends redox-based change in enzyme activity to the TCA cycle of plant mitochondria. Thioredoxin (TRX) was found to regulate the activity of enzymes of the mitochondrial cycle (succinate dehydrogenase and fumarase) and of an enzyme associated with it (ATP-citrate lyase) by modulating thiol redox status. A combination of experiments based on mutant and carbon isotope labeling analyses provides evidence that flux through this pathway is coordinately modulated by TRX at the enzyme level of both mitochondria and cytosol.

The centromere is the part of the chromosome that is involved with movement in mitosis and meiosis. The activity of the centromere is epigenetic in that the underlying DNA sequences do not necessarily determine function. In the present study, a chromosomal fragment was followed in which a sequential de novo formation and inactivation occurred for the position of the active centromere.