Genetic analysis of the naked trait in panicles of hexaploid oat

The aim of this study was to estimate the number of genes that control the naked (hull-less) trait and the mode of expression of this characteristic in panicles of hexaploid white oat. Parents and the segregating population (in the F2 and F3 generations) were evaluated in regard to the presence and distribution of naked grains in panicles of individual oat plants. For each plant, a drawing of the main panicle was developed. From the drawings obtained in the progenies of the F2 population, six distinct phenotypic classes were produced. The expected phenotypic proportion of 3:9:4 (naked:segregating:hulled) was that which best fit by the Chi-square test. In the F3 generation, the results showed agreement with the hypothesis observed in the F2 generation. The naked trait in oat is passed on by two genes and the greatest expression of this trait occurs in the upper third of the panicles. Expression of this trait in oats is not complete, even in homozygous genotypes

Genetics and identification of markers linked to multiflorous spikelet in hexaploid oat

The formation of naked grains is directly associated with the formation of multiflorous spikelets in oats. The objectives of this study were to determine the genetics of multiflorous spikelet and to identify molecular markers linked to this character in hexaploid oat. Genetic analysis for multiflorous spikelet was performed in the F5 and F6 generations of two oat populations. DNA extracted from F5:6 plants were assayed with 6,000 genome-wide single nucleotide polymorphism (SNP) markers using a genotyping platform developed for oat. Genetic analysis indicated the presence of a major gene controlling multiflorous spikelet in the UFRGS 01B7114-1-3 x UFRGS 006013-1 population. The SNP marker GMI_ES17_c5923_221 showed strong association with the multiflorous spikelet phenotype. These results suggest that the marker GMI_ES17_c5923_221 should be linked to a gene controlling multiflorous spikelet in the oat lines evaluated in this study

Subcellular visualization of gene transcripts encoding key proteins of the chlorophyll accumulation process in developing chloroplasts

The coordination of the synthesis of chlorophyll (Chl) and light-harvesting Chl proteins was determined by observing the sequence of appearance of the specific mRNAs for the nuclear genes CHLH, Por, and Lhcb1*2 (AB180). CHLH encodes a magnesium protoporphyrin chelatase subunit that is involved in the first committed step in Chl biosynthesis; Por encodes protochlorophyllide oxidoreductase, which catalyzes the penultimate and only light-dependent step in Chl biosynthesis; and Lhcb1*2 encodes light-harvesting Chl a/b binding protein of the type-1 light-harvesting complex of photosystem II. Using digoxigenin-labeled antisense and sense RNA probes and a highly sensitive in situ hybridization technique, we have visualized the first appearance of the specific mRNAs in postmitotic mesophyll cells of developing 7-d-old wheat leaves (Triticum aestivum cv Maris dove). The transcripts for CHLH and POR are detectable in the youngest (18 h postmitotic) leaf tissue containing dividing cells; light-harvesting complex of photosystem II transcripts appear 12 h later. This is consistent with a requirement for accumulation of Chl before synthesis of Chl a/b binding protein can proceed at a high rate. All of the transcripts are most abundant in mesophyll cells. In the first leaf the POR message is initially restricted to the palisade, but 12 h later it is also present in the spongy mesophyll cells. All three transcripts aggregated around the surface of the chloroplasts, suggesting that translation may occur preferentially in the vicinity of the target organelle for the primary translation products

Photosynthesis in the basal growing zone of barley leaves

Baier M, Bilger W, Wolf R, Dietz K-J. Photosynthesis in the basal growing zone of barley leaves. Photosynthesis Research. 1996;49(2):169-181