Global Dynamic Transcriptome Programming of Rapeseed (Brassica napus L.) Anther at Different Development Stages.

Rapeseed (Brassica napus L.) is an important oil crop worldwide and exhibits significant heterosis. Effective pollination control systems, which are closely linked to anther development, are a prerequisite for utilizing heterosis. The anther, which is the male organ in flowering plants, undergoes many metabolic processes during development. Although the gene expression patterns underlying pollen development are well studied in model plant Arabidopsis, the regulatory networks of genome-wide gene expression during rapeseed anther development is poorly understood, especially regarding metabolic regulations. In this study, we systematically analyzed metabolic processes occurring during anther development in rapeseed using ultrastructural observation and global transcriptome analysis. Anther ultrastructure exhibited that numerous cellular organelles abundant with metabolic materials, such as elaioplast, tapetosomes, plastids (containing starch deposits) etc. appeared, accompanied with anther structural alterations during anther development, suggesting many metabolic processes occurring. Global transcriptome analysis revealed dynamic changes in gene expression during anther development that corresponded to dynamic functional alterations between early and late anther developmental stages. The early stage anthers preferentially expressed genes involved in lipid metabolism that are related to pollen extine formation as well as elaioplast and tapetosome biosynthesis, whereas the late stage anthers expressed genes associated with carbohydrate metabolism to form pollen intine and to accumulate starch in mature pollen grains. Finally, a predictive gene regulatory module responsible for early pollen extine formation was generated. Taken together, this analysis provides a comprehensive understanding of dynamic gene expression programming of metabolic processes in the rapeseed anther, especially with respect to lipid and carbohydrate metabolism during pollen development

Inheritance and Molecular Characterization of a Novel Mutated AHAS Gene Responsible for the Resistance of AHAS-Inhibiting Herbicides in Rapeseed (Brassica napus L.)

The use of herbicides is an effective and economic way to control weeds, but their availability for rapeseed is limited due to the shortage of herbicide-resistant cultivars in China. The single-point mutation in the acetohydroxyacid synthase (AHAS) gene can lead to AHAS-inhibiting herbicide resistance. In this study, the inheritance and molecular characterization of the tribenuron-methyl (TBM)-resistant rapeseed (Brassica napus L.) mutant, K5, are performed. Results indicated that TBM-resistance of K5 was controlled by one dominant allele at a single nuclear gene locus. The novel substitution of cytosine with thymine at position 544 in BnAHAS1 was identified in K5, leading to the alteration of proline with serine at position 182 in BnAHAS1. The TBM-resistance of K5 was approximately 100 times that of its wild-type ZS9, and K5 also showed cross-resistance to bensufuron-methyl and monosulfuron-ester sodium. The BnAHAS1544T transgenic Arabidopsis exhibited higher TBM-resistance than that of its wild-type, which confirmed that BnAHAS1544T was responsible for the herbicide resistance of K5. Simultaneously, an allele-specific marker was developed to quickly distinguish the heterozygous and homozygous mutated alleles BnAHAS1544T. In addition, a method for the fast screening of TBM-resistant plants at the cotyledon stage was developed. Our research identified and molecularly characterized one novel mutative AHAS allele in B. napus and laid a foundation for developing herbicide-resistant rapeseed cultivars

Ultrafine nano-TiO2 loaded on dendritic porous silica nanoparticles for robust transparent antifogging self-cleaning nanocoatings

Multifunctional nanocoatings with mechanical robustness, high transparence, antifogging and self-cleaning have attracted significant attention because of their wide applications in glass-related fields. However, it is still very difficult to construct this kind of multifunctional nanocoatings due to the requirement of their comprehensive structure parameters. In this work, we successfully fabricated robust transparent antifogging self-cleaning nanocoatings by employing dendritic porous silica nanoparticles (DPSNs) evenly loaded with 2-3 nm of small TiO2 nanoparticles (NPs) as a building block. A series of DPSNs@X% TiO2 nanocomposites with tunable weight ratios (X%) of TiO2/DPSNs from 10% to 60% were firstly prepared by controlling the growth of TiO2 on the heterogeneous interface of center-radial large pores of DPSNs, followed by calcination. Noteworthily, DPSNs@10% TiO2 exhibited highest photocatalytic and antibacterial performance mainly due to uniform distribution of TiO2 NPs, their small sizes of 2-3 nm and center-radial pore. Therefore, DPSNs@10% TiO2 was chosen as an optimized building block and combined with acid-catalyzed silica sol (ACSS) to develop an excellent suspension for multifunctional nanocoatings. The obtained glass slide with the optimal nanocoating showed photocatalytic selfcleaning behavior, high transparence, hydrophilic (WCA = 6.2 degrees) antifogging, and high mechanical robustness, which can withstand 4B tape adhesion test and 3H pencil scratching test. This work provides an important exploration for developing multifunctional nanocoatings

Dominant patterns of transcript expression and biological processes associated with anther development in rapeseed.

<p>(a) Fifteen dominant patterns (DPs) of gene activity during rapeseed anther development. DP13, DP14 and DP15 were obtained by combining 4–7 sub-clusters with similar patterns. Detailed information is in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0154039#pone.0154039.s001" target="_blank">S1 Fig</a>. (b) Heatmap of enriched GO terms in DP1~DP12. GO terms were selected at <i>P</i><0.001, with the darker blue color representing a more significant enrichment. The <i>P</i>-value was calculated according to a hypothesis test using a cumulative hypergeometric distribution and log₁₀ transformed.</p

The morphology of samples and ultrastructural features of the anther cells during anther development in rapeseed.

<p>(a) The main inflorescence of rapeseed. (b-d) The anther development stages were correlated with the length of the flower buds in rapeseed. Small buds with lengths less than 1 mm (b) contained anthers before and during the pollen mother cell stage; middle buds with lengths of 1–3 mm (c) contained anthers from meiosis to early uninucleate microspore stages; large buds with length larger than 3 mm (d) contained anthers from vacuolated microspore to mature pollen stages. (e-t) Ultrastructural features of the anthers at the pollen mother cell stage (e-h), the meiosis stage (i-l), the early uninucleate microspore stage (m-p), the vacuolated microspore stage (q-r), and the mature pollen stage (s-t). Ep, epidermis; En, endothecium; Ml, middle layer; Tp, tapetum; PMCs, pollen mother cells; P, plastid; Ex, extine; Mt, mitochondrion; Gi, Golgi body; ER, endoplasmic reticulum; Nu, nucleus; V, vacuole; Epl, elaioplast; Ts, tapetosome; In, intine; St, starch granules; Li, lipid bodies. Scale bar in a was 1 cm; scale bars in b-d were1 mm; scale bars in e, i were 10 nm; scale bars in k, o, q, s were 5 nm; scale bars in f, g, j, l, m were 2 nm, scale bars in h, n, r, t were 1 nm.</p

The distribution of lipid and carbohydrate metabolism related genes in each dominant pattern (DP) and the expression profiles of the corresponding transcripts during rapeseed anther development.

<p>(a-b) The percentage of unique AGIs with functions related to lipid (a) or carbohydrate (b) metabolism to total unique AGIs annotated in each DP was graphed, showing a relatively high percentage of lipid metabolism genes in DP1-DP5 and a high percentage of carbohydrate metabolism genes in DP6-DP12. (c-d) The expression profiles representing transcript levels of genes involved in lipid metabolism in DP1-DP5 (c) and carbohydrate metabolism (d) in DP6-DP12.</p

The distribution of lipid and carbohydrate metabolism related transcripts identified in each dominant pattern.

<p>The distribution of lipid and carbohydrate metabolism related transcripts identified in each dominant pattern.</p