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1.
Genomic analysis of the rhg1 locus: candidate genes that underlie soybean resistance to the cyst nematode 总被引:1,自引:0,他引:1
Ruben E Jamai A Afzal J Njiti VN Triwitayakorn K Iqbal MJ Yaegashi S Bashir R Kazi S Arelli P Town CD Ishihara H Meksem K Lightfoot DA 《Molecular genetics and genomics : MGG》2006,276(6):503-516
The rhg1 gene or genes lie at a recessive or co-dominant locus, necessary for resistance to all Hg types of the soybean (Glycine max (L.) Merr.) cyst nematode (Heterodera glycines I.). The aim here was to identify nucleotide changes within a candidate gene found at the rhg1 locus that were capable of altering resistance to Hg types 0 (race 3). A 1.5 ± 0.25 cM region of chromosome 18 (linkage group G) was shown to encompass rhg1 using recombination events from four near isogenic line populations and nine DNA markers. The DNA markers anchored two bacterial artificial chromosome (BAC) clones 21d9 and 73p6. A single receptor like kinase (RLK; leucine rich repeat-transmembrane-protein kinase) candidate resistance gene was amplified from both BACs using redundant primers. The DNA sequence showed nine alleles of the RLK at Rhg1 in the soybean germplasm. Markers designed to detect alleles showed perfect association between allele 1 and resistance to soybean cyst nematode Hg types 0 in three segregating populations, fifteen additional selected recombination events and twenty-two Plant Introductions. A quantitative trait nucleotide in the RLK at rhg1 was inferred that alters A47 to V47 in the context of H297 rather than N297. Contiguous DNA sequence of 315 kbp of chromosome 18 (about 2 cM) contained additional gene candidates that may modulate resistance to other Hg-types including a variant laccase, a hydrogen-sodium ion antiport and two proteins of unknown function. A molecular basis for recessive and co-dominant resistance that involves interactions among paralagous disease-resistance genes was inferred that would improve methods for developing new nematode-resistant soybean cultivars.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
2.
Kazi S Shultz J Afzal J Johnson J Njiti VN Lightfoot DA 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(7):967-977
Soybean [Glycine max (L.) Merr.] cultivars show differences in their resistance to both the leaf scorch and root rot of sudden death syndrome
(SDS). The syndrome is caused by root colonization by Fusarium virguliforme (ex. F. solani f. sp. glycines). Root susceptibility combined with reduced leaf scorch resistance has been associated with resistance to Heterodera glycines HG Type 1.3.6.7 (race 14) of the soybean cyst nematode (SCN). In contrast, the rhg1 locus underlying resistance to Hg Type 0 was found clustered with three loci for resistance to SDS leaf scorch and one for
root infection. The aims of this study were to compare the inheritance of resistance to leaf scorch and root infection in
a population that segregated for resistance to SCN and to identify the underlying quantitative trait loci (QTL). “Hartwig”,
a cultivar partially resistant to SDS leaf scorch, F. virguliforme root infection and SCN HG Type 1.3.6.7 was crossed with the partially susceptible cultivar “Flyer”. Ninety-two F5-derived
recombinant inbred lines and 144 markers were used for map development. Four QTL found in earlier studies were confirmed.
One contributed resistance to leaf scorch on linkage group (LG) C2 (Satt277; P = 0.004, R
2 = 15%). Two on LG G underlay root infection at R8 (Satt038; P = 0.0001 R
2 = 28.1%; Satt115; P = 0.003, R
2 = 12.9%). The marker Satt038 was linked to rhg1 underlying resistance to SCN Hg Type 0. The fourth QTL was on LG D2 underlying resistance to root infection at R6 (Satt574;
P = 0.001, R
2 = 10%). That QTL was in an interval previously associated with resistance to both SDS leaf scorch and SCN Hg Type 1.3.6.7.
The QTL showed repulsion linkage with resistance to SCN that may explain the relative susceptibility to SDS of some SCN resistant
cultivars. One additional QTL was discovered on LG G underlying resistance to SDS leaf scorch measured by disease index (Satt130;
P = 0.003, R
2 = 13%). The loci and markers will provide tagged alleles with which to improve the breeding of cultivars combining resistances
to SDS leaf scorch, root infection and SCN HG Type 1.3.6.7.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
M. J. Iqbal K. Meksem V. N. Njiti My. A. Kassem D. A. Lightfoot 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(2-3):187-192
Resistance to the sudden-death syndrome (SDS) of soybean (Glycine max L. Merr.), caused by Fusarium solani f. sp. glycines, is controlled by a number of quantitatively inherited loci (QTLs). Forrest showed a strong field resistance to SDS while
Essex is susceptible to SDS. A population of 100 recombinant inbred lines (RILs) derived from a cross of Essex × Forrest was
used to map the loci effecting resistance to SDS using phenotypic data obtained from six environments. Six loci involved in
resistance to SDS were identified in this population. Four of the QTLs identified by BARC-Satt214 (P = 0.0001, R2= 24.1%), BARC-Satt309 (P = 0.0001, R2 = 16.3), BARC-Satt570 (P = 0.0001, R2 = 19.2%) and a random amplified polymorphic DNA (RAPD) marker OEO21000 (P = 0.0031, R2=12.6) were located on linkage group (LG) G (Satt309 and OEO21000 were previously reported). Jointly the four QTLs on LG G explained 50% of the variation in SDS disease incidence (DI). All
the QTLs on LG G derived the beneficial allele from Forrest. Two QTLs, BARC-Satt371 (P = 0.0019, R2 = 12%) on LG C2 (previously reported) and BARC-Satt354 (P = 0.0015, R2 = 11.5%) on LG I, derived their beneficial allele from Essex and jointly explained about 40% of the variation in SDS DI.
Two-way and multi-way interactions indicated that gene action was additive among the loci underlying resistance to SDS. These
results suggest that cultivars with durable resistance to SDS can be developed via gene pyramiding.
Received: 19 January 2000 / Accepted: 30 April 2000 相似文献
4.
’Forrest’ resistance to the soybean cyst nematode is bigenic: saturation mapping of the Rhg1and Rhg4 loci 总被引:1,自引:0,他引:1
K. Meksem P. Pantazopoulos V.N. Njiti L.D. Hyten P. R. Arelli D. A. Lightfoot 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(5):710-717
Field resistance to cyst nematode (SCN) race 3 (Heterodera glycines I.) in soybean [Glycine max (L.) Merr.] cv ’Forrest’ is conditioned by two QTLs: the underlying genes are presumed to include Rhg1 on linkage group G and Rhg4 on linkage group A2. A population of recombinant inbred lines (RILs) and two populations of near-isogenic lines (NILs) derived
from a cross of Forrest×Essex were used to map the loci affecting resistance to SCN. Bulked segregant analysis, with 512 AFLP
primer combinations and microsatellite markers, produced a high-density genetic map for the intervals carrying Rhg1 and Rhg4. The two QTLs involved in resistance to SCN were strongly associated with the AFLP marker EATGMCGA87 (P=0.0001, R2=24.5%) on linkage group G, and the AFLP marker ECCGMAAC405 (P=0.0001, R2 =26.2%) on linkage group A2. Two- way analysis of variance showed epistasic interaction (P=0.0001, R2 =16%) between the two loci controlling SCN resistance in Essex×Forrest recombinant inbred lines. Considering the two loci
as qualitative genes and the resistance as female index FI <5%, jointly the two loci explained over 98% of the resistance.
The locations of the two QTLs were confirmed in the NILs populations. Therefore SCN resistance in Forrest×Essex is bigenic.
High-efficiency marker-assisted selection can be performed using the markers to develop cultivars with stable resistance to
SCN.
Received: 5 November 2000 / Accepted: 23 January 2001 相似文献
5.
Trigonelline (TRG) is a conjugate of nicotinic acid, and is postulated to function as a compatible solute in response to salinity-
and water deficit-stresses. TRG concentrations and several agronomic characteristics were measured under irrigated field and
non-irrigated field conditions within 18 soybean (Glycine max) genotypes using leaves taken from different growth stages (vegetative, flowering and pod development). Under irrigation,
relative water content (RWC) ranged from 90.0 to 99.6 %. Under non-irrigation, RWC ranged from 86.3 to 97.5 %. TRG concentration
ranged from 364 to 555 μg g−1(d.m.) under irrigation, and from 404 to 570 μg g−1(d.m.) under non-irrigation. TRG concentrations increased in the majority of genotypes (15 of 18) under non-irrigation even
though RWC did not significantly differ in many genotypes between treatments. TRG decreased as plants progressed to pod development
and seed filling. Mean seed yield under non-irrigated conditions declined 55 % relative to the irrigated controls. TRG concentrations
among all genotypes were significantly correlated with seed yield.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Ming Gao Qun Xia Akwe W. Akwe Lakeisha Stewart Glory M. Ashu Victor Njiti 《Acta Physiologiae Plantarum》2016,38(11):259
Main conclusion
Starch granule size distributions in plant tissues, when determined in high resolution and specifiedproperly as a frequency function, could provide useful information on the granule formation and growth.Abstract
To better understand genetic control of physical properties of starch granules, we attempted a new approach to analyze developmental and genotypic effects on morphology and size distributions of starch granules in sweetpotato storage roots. Starch granules in sweetpotatoes exhibited low sphericity, many shapes that appeared to be independent of genotypes or developmental stages, and non-randomly distributed sizes. Granule size distributions of sweetpotato starches were determined in high resolution as differential volume-percentage distributions of volume-equivalent spherical diameters, rigorously curve-fitted to be lognormal, and specified using their geometric means \(\bar{x}^{*}\) and multiplicative standard deviations \(s^{*}\) in a \(\bar{x}^{*} \times /({\text{multiply/divide}})s^{*}\) form. The scale (\(\bar{x}^{*}\)) and shape (\(\bar{s}^{*}\)) of these distributions were independently variable, ranging from 14.02 to 19.36 μm and 1.403 to 1.567, respectively, among 22 cultivars/clones. The shape (\(s^{*}\)) of granule lognormal volume-size distributions of sweetpotato starch were found to be highly significantly and inversely correlated with their apparent amylose contents. More importantly, granule lognormal volume-size distributions of starches in developing sweetpotatoes displayed the same self-preserving kinetics, i.e., preserving the shape but shifting upward the scale, as those of particles undergoing agglomeration, which strongly indicated involvement of agglomeration in the formation and growth of starch granules. Furthermore, QTL analysis of a segregating null allele at one of three homoeologous starch synthase II loci in a reciprocal-cross population, which was identified through profiling starch granule-bound proteins in sweetpotatoes of diverse genotypes, showed that the locus is a QTL modulating the scale of granule volume-size distributions of starch in sweetpotatoes.7.
A study of bacterial surface oligosaccharides were investigated among
different strains of Neisseria gonorrhoeae to correlate structural features
essential for binding to the MAb 2C7. This epitope is widely expressed and
conserved in gonococcal isolates, characteristics essential to an effective
candidate vaccine antigen. Sample lipooligosaccharides (LOS), was prepared
by a modification of the hot phenol-water method from which de-O-acetylated
LOS and oligosaccharide (OS) components were analyzed by ES-MS-CID-MS and
ES-MSnin a triple quadrupole and an ion trap mass spectrometer,
respectively. Previously documented natural heterogeneity was apparent from
both LOS and OS preparations which was admixed with fragments induced by
hydrazine and mild acid treatment. Natural heterogeneity was limited to
phosphorylation and antenni extensions to the alpha-chain. Mild acid
hydrolysis to release OS also hydrolyzed the beta(1-->6) glycosidic
linkage of lipid A. OS structures were determined by collisional and
resonance excitation combined with MS and multistep MSn which provided
sequence information from both neutral loss, and nonreducing terminal
fragments. A comparison of OS structures, with earlier knowledge of MAb
binding, enzyme treatment, and partial acid hydrolysis indicates a generic
overlapping domain for 2C7 binding. Reoccurring structural features include
a Hepalpha(1-->3)Hepbeta(1-->5)KDO trisaccharide core branched on the
nonreducing terminus (Hep-2) with an alpha(1-->2) linked GlcNAc
(gamma-chain), and an alpha-linked lactose (beta-chain) residue. From the
central heptose (Hep-1), a beta(1-->4) linked lactose (alpha-chain),
moiety is required although extensions to this residue appear unnecessary.
相似文献
8.
9.
Iqbal MJ Yaegashi S Njiti VN Ahsan R Cryder KL Lightfoot DA 《Molecular genetics and genomics : MGG》2002,268(3):407-417
10.