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Background: Acetolactate synthase (ALS)-inhibiting herbicides amidosulfuron (Hoestar) is an efficient gametocide that can induce male sterility in rapeseed (Brassica napus L.). We conducted an integrated study of cytological, transcriptomic, and physiological analysis to decipher the gametocidal effect of amidosulfuron. Results: In the first several days after exposure to amidosulfuron at a gametocidal dose of ca. 1 μg per plant, the plants showed the earliest symptoms including short retard of raceme elongation, slight chlorosis on leaf, and decrease of photosynthesis rate. Chloroplasts in leaf and anther epidermis, and tapetal plastids were deformed. Both tapetal cell and uni-nucleate microspore showed autophagic vacuoles and degenerated quickly. The amidosulfuron treatment caused reduction of photosynthetic rate and the contents of leaf chlorophyll, soluble sugar and pyruvate, as well as content alteration of several free amino acids in the treated plants. A comparison of transcriptomic profiling data of the young flower buds of the treated plants with the control identified 142 up-regulated and 201 down-regulated differential expression transcripts with functional annotations. Down-regulation of several interesting genes encoding PAIR1, SDS, PPD2, HFM1, CSTF77, A6, ALA6, UGE1, FLA20, A9, bHLH91, and putative cell wall protein LOC106368794, and up-regulation of autophagy-related protein ATG8A indicated functional abnormalities about cell cycle, cell wall formation, chloroplast structure, and tissue autophagy. Ethylene-responsive transcription factor RAP2-11-like was up-regulated in the flower buds and ethylene release rate was also elevated. The transcriptional regulation in the amidosulfuron-treated plants was in line with the cytological and physiological changes. Conclusions: The results suggested that metabolic decrease related to photosynthesis and energy supply are associated with male sterility induced by amidosulfuron. The results provide insights into the molecular mechanisms of gametocide-induced male sterility and expand the knowledge on the transcriptomic complexity of the plants exposure to sulfonylurea herbicide.

Premise of the study: SP2S is a spontaneous thermo-sensitive genic male sterility (TGMS) mutation that facilitates two-line hybrid breeding in Brassica napus (Brassicaceae). De novo assembly of the floral bud transcriptome of SP2S can provide a foundation for deciphering the transcriptional regulation of SP2S in response to temperature change. Methods: mRNAs of the young floral buds of SP2S and its near-isogenic line SP2F grown under cool (16°C)/warm (22°C) conditions were sequenced on an Illumina Solexa platform, producing 239.7 million short reads with a total length of 19.95 Gbp. Results: The reads were assembled de novo using the Trinity program, resulting in 135,702 transcripts with an average length of 784 bp, an N50 value of 1221 bp, and a total length of 107 Mbp. We identified 24,157 cDNA-derived simple sequence repeats in the assembly. We found 137 and 195 single-nucleotide polymorphisms and 49 and 51 differentially regulated KEGG orthology groups when comparing sample SP2S at 22°C vs. SP2S at 16°C and sample SP2S at 22°C vs. SP2F at 22°C, respectively. Discussion: The numerous differentially expressed genes and the derived single-nucleotide polymorphisms show abnormal transcriptional regulation in the TGMS system. These results outline an intricate transcriptional regulation that occurred in the rapeseed TGMS SP2S when the temperature changed.

Xiao Z.D., Xin X.Y., Chen H.Y., Hu S.W. (2013): Cytological investigation of anther development in DGMS line Shaan-GMS in Brassica napus L. Czech J. Genet. Plant Breed., 49: 16– 23. The cytological mechanism of male sterility of Shaan-GMS, a natural mutant dominant genic male sterile (DGMS) line in Brassica napus L., is not well studied. Cytological observation was made on different-size buds of DGMS line 0A30A derived from Shaan-GMS line. The pollen mother cells (PMCs) of DGMS line 0A30A were degen erating at the beginning of meiosis and could not pass the anaphase I stage, with no dyads or tetrads formed, suggesting that the DNA damage checkpoint and spindle assembly checkpoint were activated in sterile anthers. During the meiosis process of sterile anthers in the sterile plants, several kinds of abnormal meiotic cells could be observed: nuclei condensed PMCs, cells with micronuclei, collapsed cells, plasmolysis cells, cells connected with nucleoplasmic bridge, and microspore analogue developed from PMCs without meiosis but enclosed by the exine wall. The results suggested Shaan-GMS to be a new type of DGMS line in B. napus .

Present study was conducted to evaluate the relationship between parental genetic distances, combining ability and heterosis in rapeseed (Brassica napus L.). Nine elite inbreds widely used in Chinese rapeseed breeding programs, were crossed in a diallel design to develop 36 hybrids and evaluated together with their parents across four environments. Genetic distances among lines were measured from 11 morphological traits, and SSR and SRAP molecular markers. Results showed that genetic distance evaluated by total molecular markers (GDtotal) had no correlation with heterosis. In order to make a better prediction, significant markers and favoring markers were selected from the total molecular markers, and results revealed that genetic distance measured by favoring markers (GDfavor) significantly and positively correlated with number of seeds per silique, thousand seed weight, seed yield per plant and seed yield per plot for high-check heterosis (HCK) and sum of parental general combining ability (GCA(f+m)). The selected favoring markers could be used for the further study on prediction of heterosis for yield and yield related traits. The magnitudes of correlation coefficients of morphological distances with mid-parent heterosis, high-parent heterosis and HCK for yield and other traits were mostly not significant. Interestingly, more higher levels of correlations were found between GCA(f+m) and heterosis, which indicated that using the information of GCA(f+m) to predict heterosis appeared an important method in rapeseed. Three out yielding crosses, 8D129 × 8E001 (HCK, 23.56%), 8C189 × 8C272 (23.31%), and 8C343 × 8D129 (20.08%), were identified as ideal hybrids evaluated across four environments and may be promoted for adoption and commercialization in China.

Brassica rapa L. is an important vegetable and oilseed crop. Cytoplasmic diversity of 36 B. rapa accessions was analyzed using the mitochondria-specific markers. Twelve representative materials including five additional Brassica species and one Eruca sativa Mill. were used as references. A modified multiplex PCR amplification using four pairs of primers was performed to test the mitochondrial types (mitotypes) of the tested materials. Ten accessions were detected with Cam-I mitotype which could amplify 500 and 800 bp bands, twenty-two accessions with Cam-II mitotype which could amplify 500, 800 and 906 bp bands, one accession with Pol mitotype. Interestingly, three B. rapa accessions were revealed with nap mitotype, two of them were local landraces in northern Shaanxi, the third one was a variety from Gansu province which was developed using one local landrace from Northern Shaanxi as female parent. The considerable cytoplasmic diversity in B. rapa provides useful information on studying the possible origin and evolution of B. rapa accessions, and conservation of the germplasm.

The efficiency of a novel gametocide amidosulfuron, 1-(4, 6-dimeth-oxypyrimidin- 2-yl) -3-mesyl (methyl) sulfamoylurea, was evaluated on rapeseed (Brassica napus L.). Double application of 0.09-0.12 g/ha amidosulfuron at the uni-nucleate stage of longest buds and 12 days later, made 97.4-100% plants male-sterile in seventeen out of 20 cultivars tested. The shrunken anthers could not release pollen or produced only dysfunctional pollen grains that could not be stained by aceto carmine. The treatment also caused 10-30% reduction on seed setting in comparison to the controls. The purity of hybrid seed from crosses of'C161 x Huaye' and 'Zhongshuang No.2 x Huaye' based on amidosulfuron was 99.8% and 100.0%, respectively. The results suggested that amidosulfuron is an eflicient gametocide for B. napus.

In order to fully utilize the existing geospatial data resource, reduce the building costs and complexities of GIS project, two kinds of spatial data materialized and virtual integration approaches are contrastively analyzed. The conflicts between spatial databases and the corresponding harmonizing technologies are discussed and explained. As viewed from the current application and research status, the data warehouse approach is feasible and widely used, and the approach based on Mediator/Wrapper is the research hotspot. Comparatively speaking, the automated detection and harmonization of semantic conflicts is the more difficult problem during spatial data integration and still needs the further research and survey.

Aluminum (Al) toxicity is a major constraint for wheat production in acidic soils. Wheat producers now routinely use Al-resistant cultivars as one cost-effective means to reduce risks associated with acidic soils. To date, diverse Al-resistant materials have been identified, but their genetic relationship has not been well characterized. A total of 57 wheat accessions, including the majority of the parents of Al-resistant accessions we identified in a previous study, were evaluated for Al resistance and analyzed with 49 simple sequence repeat (SSR) markers and 4 markers for Al-activated malate transporter (ALMT1). Pedigree and principle coordinate analysis (PCA) both separated Al-resistant accessions into four groups labeled according to common ancestry or geographical origin: US-Fultz, Polyssu, Mexican and Chinese. Al resistance in the four groups may have three independent origins given their distinct geographic origins and gene pools. Fultz originated in the USA as a major ancestor to soft red winter wheat, Polyssu originated in Brazil as a major source of Al resistance used in most genetic studies worldwide, and the Chinese group originated in China. Based on ALMT1 marker haplotypes, the Al resistance in the Polyssu and Mexico groups was likely derived from Polyssu, while most Al-resistant cultivars developed in the USA most likely inherited most of Al resistance from Fultz. Fultz was released about 50 years earlier than Polyssu. Norin 10 likely played a pivotal role in passing Al-resistant gene(s) from Fultz to better adapted, semi-dwarf wheat cultivars developed in the USA. Further characterization of Al resistance in the three different sources could reveal multiple Al-resistant mechanisms in wheat.

The author found a novel yellow-white flower color mutation in the male sterile progenies derived from a commercial Brassica.napus hybrid C022, which was produced by a male sterility line 9012A, whose sterility was controlled by interaction between two pairs recessive genes and a pair of epitatic genes. The mutant was named 991S. 991S had three morphologic characters:(1) The color in the middle of every petal was yellow, yet the both sides were white.(2)Every calyx might become striped albino (3) Only male sterile plants in different populations had mutative character. Except flower color, they had similar morphologic characters to the normal male sterile sib-plants. The plants were slender and little with little flowers that had flat petals, bended stigmas, degenerative stamen, and dry anthers. Primary analysis of its origin and inheritance showed that this mutative character was controlled by recessive partial albino gene.