Cloning and characterization of a novel low molecular weight glutenin subunit gene at the Glu-A3 locus from wild emmer wheat (Triticum turgidum L. var. dicoccoides)

Amplification of the coding region, and upstream and downstream sequences of a low-molecular-weight glutenin subunits (LMW-GS) gene from wild emmer wheat (Triticum turgidum L. var. dicoccoides, 2n = 4x = 28, AABB) accession TD22 was carried out using designed allele-specific PCR (AS-PCR) primers. The complete 1,176 bp sequence of a novel LMW-i type subunit gene at the Glu-A3 locus, named LMW-TD22, is described. Analysis of the nucleotide and deduced amino acid sequences showed that this gene possessed striking characteristics although its molecular structure was generally similar to those of previously reported i-type LMW-GS genes that were isolated from common wheat and related species. The deduced amino acid sequence of LMW-TD22 gene contained 390 amino acid residues with the predicted molecular weight being 43,009.3 Da, which appeared to be the longest gene among the cloned LMW-i type genes from bread wheat and related species. The distinct feature of LMW-TD22 was two long polyglutamine stretches of 12 and 17 glutamines occurring in the repetitive and C-terminal domains as well as a cysteine residue present in the seventh amino acid residue of the signal peptide. These polyglutamine repeats are believed to improve the structure of gluten polymer and increase the strength of dough formed from the polymer. In addition, the putative 44 k subunit encoded by LMW-TD22 was verified by N-terminal microsequencing, gel electrophoresis and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) analysis. Certain types of post-translational modifications, such as phosphorylation and glycosylation, may be associated with this LMW-i type subunit. A. Wang and Y. Xiao made equal contribution to the research as the first author.     

Coincident scrapie infection and nephritis lead to urinary prion excretion

Prion infectivity is typically restricted to the central nervous and lymphatic systems of infected hosts, but chronic inflammation can expand the distribution of prions. We tested whether chronic inflammatory kidney disorders would trigger excretion of prion infectivity into urine. Urinary proteins from scrapie-infected mice with lymphocytic nephritis induced scrapie upon inoculation into noninfected indicator mice. Prionuria was found in presymptomatic scrapie-infected and in sick mice, whereas neither prionuria nor urinary PrP(Sc) was detectable in prion-infected wild-type or PrP(C)-overexpressing mice, or in nephritic mice inoculated with noninfectious brain. Thus, urine may provide a vector for horizontal prion transmission, and inflammation of excretory organs may influence prion spread.     

Integrating occupancy modeling and interview data for corridor identification: A case study for jaguars in Nicaragua

Corridors are critical elements in the long-term conservation of wide-ranging species like the jaguar (Panthera onca). Jaguar corridors across the range of the species were initially identified using a GIS-based least-cost corridor model. However, due to inherent errors in remotely sensed data and model uncertainties, these corridors warrant field verification before conservation efforts can begin. We developed a novel corridor assessment protocol based on interview data and site occupancy modeling. We divided our pilot study area, in southeastern Nicaragua, into 71, 6 × 6 km sampling units and conducted 160 structured interviews with local residents. Interviews were designed to collect data on jaguar and seven prey species so that detection/non-detection matrices could be constructed for each sampling unit. Jaguars were reportedly detected in 57% of the sampling units and had a detection probability of 28%. With the exception of white-lipped peccary, prey species were reportedly detected in 82–100% of the sampling units. Though the use of interview data may violate some assumptions of the occupancy modeling approach for determining ‘proportion of area occupied’, we countered these shortcomings through study design and interpreting the occupancy parameter, psi, as ‘probability of habitat used’. Probability of habitat use was modeled for each target species using single state or multistate models. A combination of the estimated probabilities of habitat use for jaguar and prey was selected to identify the final jaguar corridor. This protocol provides an efficient field methodology for identifying corridors for easily-identifiable species, across large study areas comprised of unprotected, private lands.     

18个优质小麦品种(系)Glu-1、Glu-3和Gli-1位点的基因变异特点

为给小麦品质育种提供参考信息,选用我国18份有影响的优质面条和面包小麦品种或种质资源，通过分步法SDS-PAGE和改良A-PAGE分析了其Glu-1、Glu-3、Gli-1位点的基因变异特点。结果表明，由Glu-1住点控制的高分子量谷蛋白亚基共14种图谱，其中，Glu-A1位点上优质亚基1和2^＊分别占61．1％和11．1％，Glu—B1位点上优质亚基14＋15、7＋8、17＋18、13＋16分别占27．8％、27．8％、22．2％、5．6％．Glu_D1位点上优质亚基5＋10占55．6％。Glu—A1、Glu—B1、Glu-D1位点上均为优质亚基的品种（系）有陕451（1，7＋8，5＋10）、95鉴5104（1,14＋15，5＋10）、陕优412（2^＊，7＋8，5＋10）、绵阳89-47（2^＊，13＋16，5＋10）以及中优16、冀5099、绵优1号、绵优2号（1，17＋18,5＋10），占参试品种的44．4％。由Glu-3位点控制的低分子量谷蛋白亚基共12种图谱，小偃6号、PH82-2、陕253、80356、95鉴5104、郑农33等6个品种皆为“a，d，c”；由G1i-1位点控制的醇溶蛋白共12种图谱，小偃6号、PH82-2、陕优225、陕253、80356、中优16、95鉴5104等7个品种皆为“O，new，i”，即发现在Gli-B1位点是一个新等位基因。     

Genetic variation in germplasm accessions of Secale vavilovii Grossh

Summary The accurate identification and classification of wild species enhance the utilization of potential plant genetic resources. The wild rye species Secale vavilovii Grossh. may serve to broaden the genetic variation in cultivated rye, S. cereale. The combined analyses of cytological, isozymic and other genetic characteristics in the present study revealed that of the fourteen rye accessions designated as S. vavilovii, only three accessions were correctly classified. Thus it is essential to increase multidisciplinary, international research and collaboration to aid in the classification and utilization of the yet untapped plant germplasm.     

Powdery mildew resistance in Aegilops tauschii coss. and synthetic hexaploid wheats

Summary A collection of 400 Ae. tauschii (syn. Ae. squarrosa) Coss. accessions were screened for powdery mildew resistance based on the response patterns of 13 wheat cultivars/lines possessing major resistance genes to nine differential mildew isolates. 106 accessions showed complete resistance to all isolates, and 174 accessions revealed isolate-specific resistance, among which were 40 accessions exhibiting an identical response pattern as wheat cultivar Ulka/^*8Cc which is known to possess resistance gene Pm2. Expression of both complete and isolate-specific resistance from Ae. tauschii was observed in some synthetic hexaploid wheats derived from four mildew susceptible T. durum Desf. parents, each crossed with five to 38 resistant diploid Ae. tauschii accessions. Synthetic amphiploids involving different combinations of T. durum and Ae. tauschii generally showed a decrease in resistance compared with that expressed by the Ae. tauschii parental lines.