Wheat lines with shortened Th. ponticum chromatin carrying Fhb7 and molecular markers linked to Fhb7 will accelerate the transfer of Fhb7 to breeding lines and provide an important resource for future map-based cloning of this gene. Fusarium head blight is a major wheat disease globally. A major FHB resistance gene, designated as Fhb7, derived from Thinopyrum ponticum, was earlier transferred to common wheat, but was not used in wheat breeding due to linkage drag. The aims of this study were to (1) saturate this FHB resistance gene region; (2) develop and characterize secondary translocation lines with shortened Thinopyrum segments carrying Fhb7 using ph1b; (3) pyramid Fhb7 and Fhb1 by marker-assisted selection. Fhb7 was mapped in a 1.7 cM interval that was flanked by molecular markers XsdauK66 and Xcfa2240 with SSR, diversity arrays technology, EST-derived and conserved markers. KS24-2 carrying Fhb7 was analyzed with molecular markers and genomic in situ hybridization, confirming it was a 7DS.7el2L Robertsonian translocation. To reduce the Thinopyrum chromatin segments carrying Fhb7, a BC1F2 population (Chinese Spring ph1bph1b*2/KS24-2) was developed and genotyped with the markers linked to Fhb7. Two new translocation lines (SDAU1881 and SDAU1886) carrying Fhb7 on shortened alien segments (approximately 16.1 and 17.3% of the translocation chromosome, respectively) were developed. Furthermore, four wheat lines (SDAU1902, SDAU1903, SDAU1904, and SDAU1906) with the pyramided markers flanking Fhb1 and Fhb7 were developed and the FHB responses indicated lines with mean NDS ranging from 1.3 to 1.6 had successfully combined Fhb7 and Fhb1. Three new molecular markers associated with Fhb7 were identified and validated in 35 common wheat varieties. The translocation lines with shortened alien segments carrying Fhb7 (and Fhb1) and the markers closely linked to Fhb7 will be useful for improving wheat scab resistance.

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A solution culture experiment was conducted to investigate the effect of silicate on the yield and arsenate uptake by rice. Rice seedlings (Oryza sativa L. cv. Weiyou 77) were cultured in modified Hoagland nutrient solution containing three arsenate levels (0, 0.5 and 1.0 mg L )1 As) and four silicate levels (0, 14, 28 and 56 mg L )1 Si). Addition of Si significantly increased shoot dry weight (P ¼ 0.001) but had little effect on root dry weight (P ¼ 0.43). Addition of As had no significant effect on shoot dry weight (P ¼ 0.43) but significantly increased root dry weight (P ¼ 0.01). Silicon concentrations in shoots and roots increased proportionally to increasing amounts of externally supplied Si (P < 0.001). The presence of As in the nutrient solution had little effect on shoot Si concentration (P ¼ 0.16) but significantly decreased root Si concentration (P ¼ 0.005). Increasing external Si concentration significantly decreased shoot and root As concentrations and total As uptake by rice seedlings (P < 0.001). In addition, Si significantly decreased shoot P concentration and shoot P uptake (P < 0.001). The data clearly demonstrate a beneficial effect of Si on the growth of rice seedlings. Addition of Si to the growth medium also inhibited the uptake of arsenate and phosphate by the rice seedlings.Abbreviation: ICP-OES -inductively coupled plasma-optical emission spectrometer

The origin of angiosperms has been a long-standing botanical debate. The great diversity of angiosperms in the Early Cretaceous makes the Jurassic a promising period in which to anticipate the origins of the angiosperms. Here, based on observations of 264 specimens of 198 individual flowers preserved on 34 slabs in various states and orientations, from the South Xiangshan Formation (Early Jurassic) of China, we describe a fossil flower, Nanjinganthus dendrostyla gen. et sp. nov.. The large number of specimens and various preservations allow for an evidence-based reconstruction of the flower. From the evidence of the combination of an invaginated receptacle and ovarian roof, we infer that the seeds of Nanjinganthus were completely enclosed. Evidence of an actinomorphic flower with a dendroid style, cup-form receptacle, and angiospermy, is consistent with Nanjinganthus being a bona fide angiosperm from the Jurassic, an inference that we hope will re-invigorate research into angiosperm origins.