Polyploidy has been a prevalent process during plant evolution and it has made a major impact on the structure and evolution of plant genomes. Many important crop plants are polyploid. There is considerable interest in expression patterns of duplicated genes in polyploids. Alternative splicing (AS) is a fundamental aspect of gene expression that produces multiple final transcript types from a single type of mRNAs. The effects of abiotic stress conditions on AS in polyploids has received little attention. We conducted a global transcriptome analysis of Brassica napus , an allotetraploid derived from B. rapa (A _T ) and B. oleracea (C _T ), by RNA‐Seq of plants subjected to cold, heat, and drought stress treatments. Analyses of 27,360 pairs of duplicated genes revealed overall A _T subgenome biases in gene expression and C _T subgenome biases in the extent of alternative splicing under all three stress treatments. More genes increased in expression than decreased in response to the stresses. Negative correlations were found between expression levels and AS frequency for each type of AS. Cold stress produced the greatest changes in gene expression and AS. Cold‐induced AS changes were more likely to be shared with those generated by drought than by heat stress. We used homeologs of FLC and CCA1 as case studies to show the dynamics of how duplicates in a polyploid respond to cold stress. Our results suggest that divergence in gene expression and AS patterns between duplicated genes may increase the flexibility of polyploids when responding to abiotic stressors.

A Gram-staining-negative, strictly aerobic, white-colony-forming bacterium, designated strain 5-10^T, was isolated from forest soil of Bac Kan Province in Vietnam. Cells were non-motile rods or coccoids, showing oxidase- and catalase-positive reactions. Growth was observed at 10–37 °C (optimum, 30 °C), at pH 5.0–9.0 (optimum, pH 7.0) and in the presence of 0–1.0 % (w/v) NaCl (optimum, 0–0.5 %). The major cellular fatty acids were summed feature 3 (comprising C_16 : 1ω6c and/or C_16 : 1ω7c), C_16 : 0, C_10 : 0 3-OH and summed feature 8 (comprising C_18 : 1ω6c and/or C_18 : 1ω7c). The G+C content of the genomic DNA was 69.9 mol% and the only respiratory quinone detected was ubiquinone 8 (Q-8). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 5-10^T formed a tight phyletic lineage with members of the genus Ramlibacter . Strain 5-10^T was most closely related to Ramlibacter tataouinensis TTB310^T (97.3 %), but the DNA–DNA relatedness level between the two strains was 38.2±1.8 %. Based on phenotypic, chemotaxonomic and molecular features, strain 5-10^T was shown to represent a novel species of the genus Ramlibacter , for which the name Ramlibacter solisilvae sp. nov. is proposed. The type strain is 5-10^T ( = KACC 17567^T = JCM 19319^T). An emended description of the genus Ramlibacter is also proposed.

Proto‐Araceae, the earliest diverged lineage within the family Araceae, includes two subfamilies, Gymnostachydoideae (one species) and Orontioideae (eight species). Based on an extensive sampling (a total of 198 accessions) of six chloroplast non‐coding regions (5799 aligned sites), we assessed phylogenetic relationships among the genera and species within subfamily Orontioideae and estimated the timing of intercontinental disjunct events in the Northern Hemisphere. Overall phylogenetic relationships among the genera were consistent with results from previous studies, but several new important findings were discovered, primarily within Symplocarpus Salisb. ex W. P. C. Barton. First, two major lineages within Symplocarpus were identified: one lineage included S. foetidus (L.) Salisb. ex W. Barton, S. nabekuraensis Otsuka & K. Inoue, and S. renifolius Schott ex Tzvelev (Japan), whereas the other included S. nipponicus Makino, S. egorovii N. S. Pavlova & V. A. Nechaev, and S. renifolius (Korea). Symplocarpus renifolius in Japan was tetraploid and closely related to the tetraploid S. foetidus in eastern North America. Populations of S. renifolius in Korea were confirmed to be diploid (2n = 30) and shared the most recent common ancestor with the other diploid species, S. nipponicus. Second, two recently described species, S. nabekuraensis and S. egorovii, were deeply embedded within S. renifolius in Japan and Korea, respectively, and their distinct taxonomic status requires further assessment. Finally, two intercontinental disjunction events in the subfamily, one in Lysichiton Schott between eastern Asia and western North America and the other in Symplocarpus between eastern Asia and eastern North America, were estimated to be between 4.5 and 1.4 million years ago (Pliocene and Pleistocene) and between 1.9 and 0.5 million years ago (Pleistocene), respectively.

Approximately 10% of agricultural land is subject to periodic flooding, which reduces the growth, survivorship, and yield of most crops, reinforcing the need to understand and enhance flooding resistance in our crops. Here, we generated RNA-Seq data from leaf and root tissue of domesticated sunflower to explore differences in gene expression and alternative splicing (AS) between a resistant and susceptible cultivar under both flooding and control conditions and at three time points. Using a combination of mixed model and gene co-expression analyses, we were able to separate general responses of sunflower to flooding stress from those that contribute to the greater tolerance of the resistant line. Both cultivars responded to flooding stress by upregulating expression levels of known submergence responsive genes, such as alcohol dehydrogenases, and slowing metabolism-related activities. Differential AS reinforced expression differences, with reduced AS frequencies typically observed for genes with upregulated expression. Significant differences were found between the genotypes, including earlier and stronger upregulation of the alcohol fermentation pathway and a more rapid return to pre-flooding gene expression levels in the resistant genotype. Our results show how changes in the timing of gene expression following both the induction of flooding and release from flooding stress contribute to increased flooding tolerance.