Biomedical subjects

Jun-Yi Gai

Publications and source records attributed to Jun-Yi Gai.

13 recordsLinked to original sources

PubMed2006

Cloning and comparative analysis of the gene encoding diacylglycerol acyltransferase from wild type and cultivated soybean.

Diacylglycerol acyltransferase (DGAT), as an important enzyme in triacylglycerol synthesis, catalyzes the final acylation of the Kennedy pathway. In the present study, the GmDGAT gene was cloned from Glycine max by using AtDGAT as a query to search against the soybean EST database and the rapid amplification of cDNA ends (RACE) method. Allelic genes were also isolated from 13 soybean accessions and the divergence of the deduced amino acid sequences were compared. The comparison reveals that although GmDGAT is a highly conserved protein, several differences of insertion/deletion were identified in the N-terminal region of the GmDGATs from various soybean accessions. In the C-terminal regions, a single amino acid mutation specific to both G. max and G. soja was also found. The GmDGAT genomic sequences were further cloned and the number and size of exons in the DGAT genomic sequence were very similar among different plant species, whereas the introns were more diverged. These results may have significance in elucidating the genetic diversity of the GmDGAT among the soybean subgenus.

Amino Acid Sequence↗

PubMed2006

[Crude extraction and activity assay of CEL I].

CEL I, extracted from celery, is the first known eukaryotic nuclease that cleaves DNA with high specificity at sites of base-substitution mismatch and DNA distortion. It is a key enzyme for TILLING research. Here we reported a crude extraction method and activity assay of CEL I. Incision at mismatches of single nucleotide suggested that CEL I can effectively detect DNA at G-->A base substitution and the result can be obtained from an ABI377 Sequencer. Therefore, the extracted enzyme can be used in TILLING.

Apium↗

PubMed2006

[Genetic analysis and RAPD marker of the genes for brachytic stem trait in soybean].

Three crosses between NG94-156 (brachytic stem) and three varieties (normal stem) were made, and F2 segregative population and two recombined inbred line populations(F(7:8)) were obtained. Genetic analysis indicated that the brachytic stem of NG94-156 was controlled by two duplicate recessive genes. In searching for RAPD marker linked to the genes controlling brachytic stem, 260 RAPD primers were applied to screen four parents of three combinations and RIL. Polymorphic bands revealed by the primer S-506 exhibited the best repeatability among all primers. Linkage analysis indicated the genetic distance between S-506(1600) and brachytic stem gene was 6.94 cM.

Genetic Linkage↗

PubMed2005

[Segregation analysis of genetic system of quantitative traits in plants].

Based on the traditional polygene inheritance model of quantitative traits, the mixed major gene and polygene inheritance model was raised and considered as the general model, while pure major gene or pure polygene inheritance model being only the specific case of the general model. From the proposed theory, the segregation analysis procedure was established for studying the genetic system of quantitative traits of plants. At present this procedure can be used to evaluate the genetic effects of individual major genes (up to 2-3 major genes) and the collective genetic effects of polygenes as well as their heritability values. The present paper introduces the process of the establishment of the procedure, main achievements and application results. An example was given to illustrate the steps, methods and effectiveness of the procedure.

Crosses, Genetic↗

PubMed2005

[Identification of drought tolerant germplasm and inheritance and QTL mapping of related root traits in soybean (Glycine max (L.) Merr.)].

Fifty nine accessions of soybean (Glycine max (L.) Merr.) selected from 301 ones in Huang-Huai-Hai and Middle-Lower Changjiang Valleys were tested in two years for their tolerance to drought by using the mean membership index value averaged over those of plant height,leave number,dry root weight and dry stem and leaf weight. Four most tolerant accessions (Rank 1) and two most sensitive ones (Rank 5) were identified. There existed very significant correlations between drought tolerance and relative values of dry root weight,total root length, and root volume (per plant dry weight basis), respectively,which could be used as root indicators of drought tolerance. The RIL population derived from Kefeng 1 x Nannong 1138-2 was used to analyze the inheritance of the three related root traits by using the segregation analysis of quantitative traits under the major gene plus polygene mixed inheritance model. The results showed that between the two parents (Rank 1 x Rank 4), the relative values of dry root weight,total root length and root volume were respectively controlled by two major genes (linked together for the latter two traits, recombination value being 4.30% and 1.93%, respectively) plus polygenes with their major gene heritability values of 62.26%-91.81% and polygene heritability values 2.99%-24.75%, indicating that the major genes,especially the one with larger effect,accounted for a major part of the genetic variation between the two parents. It was identified that five, three, and five QTLs located on N6-C2, N8-D1b + W, N11-E, and N18-K linkage groups for relative dry root weight, total root length and root volume, respectively. Each of the traits appeared to have one locus (Dw1, R/1, and Rv1) with relatively large effect in comparison with their other loci, and those major ones were located near the same site of the same linkage group N6-C2. The results of segregation analysis and QTL mapping appeared pretty consistent with each other, which could be used as a demonstration of each other.

Adaptation, Physiological↗

PubMed2004

[Mapping of five genes resistant to SMV strains in soybean].

Soybean mosaic virus (SMV) is one of the most prevalent pathogens that impact the soybean world widely. Previous reports showed that most of the resistances were controlled by one pair of dominant genes. In this study, a soybean RIL population NJRIKY derived from Kefeng 1 x Nannong 1138-2 was used to study the inheritance of resistance to five SMV strains (Sa,Sc-8, Sc-9, N1, and N3) and mapping of resistant genes. Kefeng 1 is resistant to all five SMV strains while Nannong 1138-2 is susceptible to all five SMV strains. The parents and RIL populations were planted in green house and five SMV strains were inoculated on different populations. The results showed that each ratio of the number of resistant families to that of susceptible families was consistent with 1:1 for the five strains. This indicated that the resistance to each of the five strains was controlled by one dominant gene, respectively. RFLP and SSR markers were used to analyze the RIL population, Mapmaker/Exp 3.0b was used to study the linkage between markers and the resistant genes. Through linkage analysis, Rsa was found linked Rn1, Rn3 and Rsc9 with 21.4 cM, 23.5 cM and 35.3 cM, Rsc8 was found to be linked only Rn1 with 35.8 cM. Multi locus analysis showed that the order and intervals of the five resistance genes were Rsc8-35.8 cM-Rn1-10.3 cM-Rn3-21.5 cM- Rsa-35.8 cM-Rsc9. According to the result of RFLP and SSR analysis, a genetic map was constructed which consisted of 256 markers that covered 3050.9 cM and converged into 22 linkage groups. The five resistance genes were mapped on the linkage group N8-D1b + W. The RFLP markers A691T, K4771, LC5T were found linked to the resistant genes Rn1 and Rn3 with distances of 15.04 cM, 17.82 cM, 15.37 cM, 16.14 cM, 17.82 cM, 16.58 cM.

Chromosome Mapping↗

PubMed2004

[Mapping QTLs of soybean root weight with RIL population NJRIKY].

The recombinant inbred line (RIL) population, NJRIKY with 184 families derived from a cross Kefeng No.1 x Nannong1138-2 was used in mapping QTLs of root weight of soybean. Based on the linkage map constructed by Wang, with the software Cartographer V. 1.21 of the composite interval mapping procedure, three QTLs of root weight were mapped on N3-B1 and N6-C2 linkage group. The left telomere distance of rw1 was 66.31cM on N3-B1 linkage group, and those of rw2 and rw3 were 169.91cM and 179.71 cM, respectively, on N6-C2 linkage group. The former was located in A520T approximately ACCCAGO5 and the latter were overlapped with OPW13 and ACGCATO6, respectively. Their LOD values were 10.34,4.01 and 3.15, respectively. The QTLs of the root weight explained 26.3%,9.2% and 6.8% of the total variation, and their additive effects were -0.514,-0.303 and -0.260, respectively.

Chromosome Mapping↗

PubMed2004

[Analysis on the major gene and multigene mixed inheritance of wide compatibility gene in rice].

The intersubspecific hybrids between Indica and Japanica varieties are generally semi sterile, which limits the use of Indica-Japanica heterosis. Genetic study of wide compatibility gene (WCG) in rice helps to understand the mechanism of semi sterility and make it possible to overcome this phenomenon. In this study, the P1,P2,F1,B1,B2,and F2 of Indica-Japanica hybrid of 3037/02428 were analyzed by the major gene and minor gene mixed inheritance model. The research showed that Apart from single major gene, the WCG inheritance is also affected by minor genes. Not only major gene's effect on fertility but also minor gene's effect should be considered when utilize WCG to overcome semisterile between subspecies.

Crosses, Genetic↗

PubMed2003

Isolation and characterization of a Pti1 homologue from soybean.

A full-length gene GmPti1 was identified from soybean in an EST sequencing project by its homology to tomato Pti1. It encoded a protein of 366 amino acids. RT-PCR analysis showed that the GmPti1 expression was induced by salicylic acid and wounding. The deduced amino acid sequence had a Ser/Thr/Tyr kinase domain. GmPti1 protein was expressed in E. coli as an MBP fusion, purified by amylose resin and examined for its autophosphorylation ability. The phosphorylation assay in vitro showed that GmPti1 had kinase activity in the presence of Mn2+. These results demonstrated that GmPti1 represented a new Pti1-like gene, unlike the two published genes sPti1a and sPti1b, which encoding proteins had no autophosphorylation ability.

Amino Acid Sequence↗

PubMed2003

Genomic characterization of the S-adenosylmethionine decarboxylase genes from soybean.

A full-length gene GmSAMDC1, encoding the S-adenosylmethionine decarboxylase (SAMDC), a key enzyme involved in polyamine biosynthesis, was identified from soybean expressed sequence tags and was characterized. GmSAMDC1 encoded a peptide of 355 amino acids. When compared with other plant SAMDCs, the GmSAMDC1 protein had several highly conserved regions including a putative pro-enzyme cleavage site and a PEST sequence. The 5' leader sequence of the the GmSAMDC1 mRNA contained two additional open reading frames (ORFs), which may regulate the translational process. The genomic sequence of the GmSAMDC1 gene contained three introns in the 5' leader sequence, but no intron in the 3'-UTR or the main pro-enzyme ORF. A simple sequence repeat (SSR) was found in intron 2, and the GmSAMDC1 gene was mapped to linkage group D1 using this SSR. The genomic organization of the GmSAMDC1 gene in the subgenus Glycine and the subgenus Soja was found to be different by Southern-blot and PCR analysis. A pseudogene, GmSAMDC2, was also identified. This gene contained no intron and lost its two uORFs. Northern-blot analysis showed that the GmSAMDC1 gene expression was induced by salt, drought and cold, but not induced by wounding; suggesting that the gene was implicated in response to multiple-stress conditions.

3' Untranslated Regions↗

PubMed2003

The EIM algorithm in the joint segregation analysis of quantitative traits.

In this article, a new algorithm for obtaining the maximum likelihood estimators (MLEs) of parameters in the joint segregation analysis (JSA) of multiple generations of P1, F1, P2, F2 and F2:3 (MG5) for quantitative traits was set up. Firstly, owing to the fact that the component variance of the heterogeneous genotype in F2:3 included both the first-order genetic parameters (denoted by the means of distributions) and the second-order parameters, a simple closed form for the MLEs of the means of component distributions did not exist while the expectation and maximization (EM) algorithm was used. To simplify the estimation of parameters, the first partial derivative of the above variance on the mean in the sample log-likelihood function was omitted. However, this would be remedied by the iterated method. Then, variances of component distributions for segregating populations were partitioned into major-gene, polygenic and environmental variances so that the generally iterated formulae for estimating the means as well as polygenic and environmental variances of component distributions in the maximization step (M-step) of the EM algorithm were obtained. Therefore, the EM algorithm for estimating parameters in the JSA model for the MG5 was simplified. This is called the expectation and iterated maximization (EIM) algorithm. Finally, an example of the inheritance of the resistance of soybean to beanfly showed that the results of mixed inheritance analysis in this paper coincided with those in both Wang & Gai (2001) and Wei et al. (1989), so the EIM algorithm was appropriate.

Algorithms↗

PubMed2003

[Mapping the trait controlled by two duplicate genes in the DH or RIL population].

While there is linkage between molecular marker and trait controlled by two duplicate genes in the DH or RIL population, the recombination rate (RR) between molecular marker and one gene controlling the above trait may be estimated by the maximum likelihood method. Moreover, the standard deviation of RR was also obtained in this paper. Finally, the results from Monte Carlo simulation with 3000 replications showed that the unbiasedness of RR for various sample size and RR was good, and the variation of the estimated value of RR decreased with the increase of sample size or RR.

English Abstract↗

PubMed2002

Isolation and characterization of a full-length resistance gene homolog from soybean.

Using mixed resistance gene analogs as probes, a putative resistance gene (KR1) was isolated from soybean and characterized further. The KR1 protein consists of a Toll/interleukin receptor (TIR) domain, a nucleotide binding site (NBS) domain, an imperfect leucine-rich repeat (LRR) domain and two C-terminal transmembrane segments. Due to these features, KR1 represents a distinct member in the TIR-NBS-LRR class of resistance genes. Southern-blot analysis indicated that there were several KR1-related sequences within the soybean genome, and two polymorphic loci were mapped onto linkage group L. KR1 was induced by SA treatment and soybean mosaic virus (SMV) infection in the resistant line (Kefeng 1). An orthologue (NR1) and a homologue (NR2) of the KR1 gene were also identified in the SMV susceptible-line Nannong1138-2. Sequencing analysis revealed that NR2 was highly homologous to KR1 and NR1, but had a 21-bp deletion. Moreover, the NR1, NR2 transcription and the ratio of NR1/ NR2 was up-regulated by viral infection in Nannong1138-2. These results indicated the complexity of the regulatory mechanism in the plant responses to SMV infection.

Amino Acid Sequence↗