Fusarium species cause serious diseases in cereal staple food crops such as wheat and maize. Currently, the mechanisms underlying resistance to Fusarium-caused diseases are still largely unknown. In the present study, we employed a combined proteomic and transcriptomic approach to investigate wheat genes responding to F. graminearum infection that causes Fusarium head blight (FHB). We found a total of 163 genes and 37 proteins that were induced by infection. These genes and proteins were associated with signaling pathways mediated by salicylic acid (SA), jasmonic acid (JA), ethylene (ET), calcium ions, phosphatidic acid (PA), as well as with reactive oxygen species (ROS) production and scavenging, antimicrobial compound synthesis, detoxification, and cell wall fortification. We compared the time-course expression profiles between FHB-resistant Wangshuibai plants and susceptible Meh0106 mutant plants of a selected set of genes that are critical to the plants' resistance and defense reactions. A biphasic phenomenon was observed during the first 24 h after inoculation (hai) in the resistant plants. The SA and Ca2+ signaling pathways were activated within 6 hai followed by the JA mediated defense signaling activated around 12 hai. ET signaling was activated between these two phases. Genes for PA and ROS synthesis were induced during the SA and JA phases, respectively. The delayed activation of the SA defense pathway in the mutant was associated with its susceptibility. After F. graminearum infection, the endogenous contents of SA and JA in Wangshuibai and the mutant changed in a manner similar to the investigated genes corresponding to the individual pathways. A few genes for resistance-related cell modification and phytoalexin production were also identified. This study provided important clues for designing strategies to curb diseases caused by Fusarium.

Bread wheat (Triticum aestivum L.) is a hexaploid species with a large and complex genome. A reference genetic marker map, namely the International Triticeae Mapping Initiative (ITMI) map, has been constructed with the recombinant inbred line population derived from a cross involving a synthetic line. But it is not sufficient for a full understanding of the wheat genome under artificial selection without comparing it with intervarietal maps. Using an intervarietal mapping population derived by crossing Nanda2419 and Wangshuibai, we constructed a high-density genetic map of wheat. The total map length was 4,223.1 cM, comprising 887 loci, 345 of which were detected by markers derived from expressed sequence tags (ESTs). Two-thirds of the high marker density blocks were present in interstitial and telomeric regions. The map covered, mostly with the EST-derived markers, approximately 158 cM of telomeric regions absent in the ITMI map. The regions of low marker density were largely conserved among cultivars and between homoeologous subgenomes. The loci showing skewed segregation displayed a clustered distribution along chromosomes and some of the segregation distortion regions (SDR) are conserved in different mapping populations. This map enriched with EST-derived markers is important for structure and function analysis of wheat genome as well as in wheat gene mapping, cloning, and breeding programs.

a b s t r a c tNitrogen plays an important role in plant growth and development. Nitrate transporters have been extensively studied in Arabidopsis, but in tomato they have not been functionally characterized. In this study, we report the functions of LeNRT2.3 in nitrate transport in tomato. Our results show that LeNRT2.3 is induced by nitrate, and mainly localizes to the plasma membranes of rhizodermal and pericycle cells in roots. Further analysis in Xenopus oocytes showed that LeNRT2.3 mediates lowaffinity nitrate transport. 35S:LeNRT2.3 increased nitrate uptake in root and transport from root to shoot. More interestingly, 35S:LeNRT2.3 showed high biomass and fruit weight. Taken together, these results suggest that LeNRT2.3 plays a double role in nitrate uptake and long-distance transport in tomato.

Anomalous passive Q-switching behavior was demonstrated in an Yb:KLu(WO 4 ) 2 laser, with a Cr 4+ :YAG crystal plate acting as saturable absorber whose initial transmission amounted to 99.3%. In stable Q-switched operation realized under high output coupling of 80%, 1.83 W of average output power was produced at a pulse repetition rate of 0.97 MHz, far beyond the upper limit imposed by the recovery time of the saturable absorber. The largest pulse energy, shortest pulse duration, and highest peak power were, respectively, 1.89 µJ, 39 ns, and 48.5 W. The high-repetition-rate passive Q-switching performance shows a close similarity to some Yb-ion lasers passively Q-switched by 2D saturable absorbers.

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We report on the passive Q-switching laser performance of the Yb:Gd3Ga5O12 garnet crystal. With a Cr4+:YAG crystal used as saturable absorber for passive Q-switching, an average output power of 5.31 W was produced at a pulse repetition rate of 62.5 kHz, the optical-to-optical and slope efficiencies being, respectively, 45% and 61%. Laser pulses of 140 μJ in energy and 5.8 ns in duration were also obtained at 22.2 kHz, with a corresponding peak power amounting to 24.1 kW.

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