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101.
Fine genetic mapping fails to dissociate durable stem rust resistance gene Sr2 from pseudo-black chaff in common wheat (Triticum aestivum L.) 总被引:2,自引:0,他引:2
Kota R Spielmeyer W McIntosh RA Lagudah ES 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(3):492-499
The broad-spectrum stem rust resistance gene Sr2 has provided protection in wheat against Puccinia graminis Pers. f. sp. tritici for over 80 years. The Sr2 gene and an associated dark pigmentation trait, pseudo-black chaff (PBC), have previously been localized to the short arm
of chromosome 3B. In a first step towards the positional-based cloning of Sr2, we constructed a high-resolution map of this region. The wheat EST (wEST) deletion bin mapping project provided tightly
linked cDNA markers. The rice genome sequence was used to infer the putative gene order for orthologous wheat genes and provide
additional markers once the syntenic interval in rice was identified. We used this approach to map six wESTs that were collinear
with the physical order of the corresponding genes on rice chromosome 1 suggesting there are no major re-arrangements between
wheat and rice in this region. We were unable to separate by recombination the tightly linked morphological trait, PBC from
the stem rust resistance gene suggesting that either a single gene or two tightly linked genes control both traits. 相似文献
102.
The phylogenetic position of Rhopalura ophiocomae (Orthonectida) based on 18S ribosomal DNA sequence analysis 总被引:2,自引:0,他引:2
Hanelt B; Van Schyndel D; Adema CM; Lewis LA; Loker ES 《Molecular biology and evolution》1996,13(9):1187-1191
The Orthonectida is a small, poorly known phylum of parasites of marine
invertebrates. Their phylogenetic placement is obscure; they have been
considered to be multicellular protozoans, primitive animals at a
"mesozoan" grade of organization, or secondarily simplified flatworm- like
organisms. The best known species in the phylum, Rhopalura ophiocomae, was
collected on San Juan Island, Wash. and a complete 18S rDNA sequence was
obtained. Using the models of minimum evolution and parsimony, phylogenetic
analyses were undertaken and the results lend support to the following
hypotheses about orthonectids: (1) orthonectids are more closely aligned
with triploblastic metazoan taxa than with the protist or diploblastic
metazoan taxa considered in this analysis; (2) orthonectids are not derived
members of the phylum Platyhelminthes; and (3) orthonectids and rhombozoans
are not each other's closest relatives, thus casting further doubt on the
validity of the phylum Mesozoa previously used to encompass both groups.
相似文献
103.
Background
The omics fields promise to revolutionize our understanding of biology and biomedicine. However, their potential is compromised by the challenge to analyze the huge datasets produced. Analysis of omics data is plagued by the curse of dimensionality, resulting in imprecise estimates of model parameters and performance. Moreover, the integration of omics data with other data sources is difficult to shoehorn into classical statistical models. This has resulted in ad hoc approaches to address specific problems. 相似文献104.
A sodium transporter (HKT7) is a candidate for Nax1, a gene for salt tolerance in durum wheat 下载免费PDF全文
Huang S Spielmeyer W Lagudah ES James RA Platten JD Dennis ES Munns R 《Plant physiology》2006,142(4):1718-1727
Durum wheat (Triticum turgidum subsp. durum) is more salt sensitive than bread wheat (Triticum aestivum). A novel source of Na(+) exclusion conferring salt tolerance to durum wheat is present in the durum wheat Line 149 derived from Triticum monococcum C68-101, and a quantitative trait locus contributing to low Na(+) concentration in leaf blades, Nax1, mapped to chromosome 2AL. In this study, we used the rice (Oryza sativa) genome sequence and data from the wheat expressed sequence tag deletion bin mapping project to identify markers and construct a high-resolution map of the Nax1 region. Genes on wheat chromosome 2AL and rice chromosome 4L had good overall colinearity, but there was an inversion of a chromosomal segment that includes the Nax1 locus. Two putative sodium transporter genes (TmHKT7) related to OsHKT7 were mapped to chromosome 2AL. One TmHKT7 member (TmHKT7-A1) was polymorphic between the salt-tolerant and -sensitive lines, and cosegregated with Nax1 in the high-resolution mapping family. The other TmHKT7 member (TmHKT7-A2) was located within the same bacterial artificial chromosome contig of approximately 145 kb as TmHKT7-A1. TmHKT7-A1 and -A2 showed 83% amino acid identity. TmHKT7-A2, but not TmHKT7-A1, was expressed in roots and leaf sheaths of the salt-tolerant durum wheat Line 149. The expression pattern of TmHKT7-A2 was consistent with the physiological role of Nax1 in reducing Na(+) concentration in leaf blades by retaining Na(+) in the sheaths. TmHKT7-A2 could control Na(+) unloading from xylem in roots and sheaths. 相似文献
105.
Seed survival and dispersal of an endemic Atlantic forest palm: the combined effects of defaunation and forest fragmentation 总被引:3,自引:0,他引:3
MAURO GALETTI CAMILA I. DONATTI ALEXANDRA S. PIRES PAULO R. GUIMARÃES JR PEDRO JORDANO 《Botanical journal of the Linnean Society. Linnean Society of London》2006,151(1):141-149
About 45 palm species occur in the Atlantic forest of Brazil, and most of them are affected by loss of seed dispersers resulting from forest fragmentation and hunting. Here we report the effects of habitat loss and defaunation on the seed dispersal system of an endemic palm, Astrocaryum aculeatissimum . We evaluated seed removal, insect and rodent seed predation, and scatter-hoarding in nine sites, ranging from 19 ha to 79 000 ha. We report the seedling, juvenile and adult palm densities in this range of sites. Endocarps remaining beneath the parent palm had a higher probability of being preyed upon by insects in small, mostly fragmented and more defaunated sites. The frequency of successful seed removal, scatter-hoarding and consumption by rodents increased in the larger, less defaunated sites. Successful removal and dispersal collapsed in small (< 1000 ha), highly defaunated sites and frequently resulted in low densities of both seedlings and juveniles. Our results indicate that a large fraction of Atlantic forest palms that rely on scatter-hoarding rodents may become regionally extinct due to forest fragmentation and defaunation. Current management practices including palm extraction and hunting pressure have a lasting effect on Atlantic forest palm regeneration by severely limiting successful recruitment of prereproductive individuals. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 141–149. 相似文献
106.
Mago R Tabe L McIntosh RA Pretorius Z Kota R Paux E Wicker T Breen J Lagudah ES Ellis JG Spielmeyer W 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(4):615-623
Sr2 is the only known durable, race non-specific adult plant stem rust resistance gene in wheat. The Sr2 gene was shown to be tightly linked to the leaf rust resistance gene Lr27 and to powdery mildew resistance. An analysis of recombinants and mutants suggests that a single gene on chromosome arm 3BS may be responsible for resistance to these three fungal pathogens. The resistance functions of the Sr2 locus are compared and contrasted with those of the adult plant resistance gene Lr34. 相似文献
107.
108.
Zea systematics: ribosomal ITS evidence 总被引:10,自引:0,他引:10
Ribosomal internal transcribed spacer (ITS) sequences were used to evaluate
the phylogenetics of Zea and Tripsacum. Maximum likelihood and polymorphism
parsimony were used for phylogenetic reconstructions. Zea ITS nucleotide
diversity was high compared to other plant species, but approximately
equivalent to other maize loci. Coalescence of ITS alleles was rapid
relative to other nuclear loci; however, there was still much diversity
within populations. Zea and Tripsacum form a clade clearly differentiated
from all other Poaceae. Four Zea ITS pseudogenes were identified by
phylogenetic position and nucleotide composition. The phylogenetic position
of Z. mays ssp. huehuetenangensis was clearly established as basal to the
other Z. mays. The ITS phylogeny disfavored a Z. luxurians and Z.
diploperennis clade, which conflicted with some previous studies. The
introgression of Z. mays alleles into Z. perennis and Z. diploperennis was
also established. The ITS data indicated a near contemporary divergence of
domesticated maize and its two closest wild relatives.
相似文献
109.