利用重组自交系和SSR标记进行陆地棉株型QTL的鉴定和定位

通过中棉所12与8891的杂交及多代自交,获得由180个家系构成的重组自交系F8、F9群体。重组自交系群体、两亲本及F1于2002、2003两年种植;对株型性状进行了研究,两年共调查了10个株型形状。利用该重组自交系群体,采用SSR为主体的分子标记构建了遗传连锁图,并对株型性状进行了单位点和双位点水平的QTL定位。结果表明,QTL加性效应和上位性互作效应作为棉花重组自交系株型性状的遗传基础起着重要作用;中棉所12与8891间多态性位点偏少,而表型差异较大且其杂交种湘杂棉二号有很强的杂种优势,QTL互作可部分解释这一现象：结合对产量品质性状的研究结果,认为上位性可能是湘杂棉二号杂种优势的重要遗传基础。     

Molecular Tagging and Mapping of Quantitative Trait Loci for Lint Percentage and Morphological Marker Genes in Upland Cotton

Using 219 F2 Individuals developed by crossing the genetic standard line TM-1 and the multiple dominant marker line T586 In Gossyplum hirsutum L., a genetic linkage map with 19 linkage groups was constructed based on simple sequence repeat （SSR） markers. Compared with our tetraploid backboned molecular genetic map from a （TM-1xHal 7124）xTM-1 BC1 population, 17 of the 19 I｜nkage groups were combined and anchored to 12 chromosomes （sub-genomes）. Of these groups, four morphological marker genes In T586 had been mapped Into the molecular linkage map. Meanwhile, three quantitative trait loci for lint percentage were tagged and mapped separately on the A03 linkage group and chromosome 6.     

Quantitative Trait Loci Mapping of Leaf Morphological Traits and Chlorophyll Content in Cultivated Tetraploid Cotton

Genetic mapping provides a powerful tool for quantitative trait loci （QTL） analysis at the molecular level. A simple sequence repeat （SSR） genetic map containing 590 markers and a BCI population from two cultivated tetraploid cotton （Gossypium hirsutum L.） cultivars, namely TM-1 and Hai 7124 （G. barbadense L.）, were used to map and analyze QTL using the composite interval mapping （CIM） method. Thirty one QTLs, 10 for lobe length, 13 for lobe width, six for lobe angle, and two for leaf chlorophyll content, were detected on 15 chromosomes or linkage groups at logarithm of odds （LOD）≥2.0, of which 15 were found for leaf morphology at LOD≥3.0. The genetic effects of the QTL were estimated. These results are fundamental for marker-assisted selection （MAS） of these traits in tetraploid cotton breeding.     

Construction of a Bacterial Artificial Chromosome Library of TM-1, a Standard Line for Genetics and Genomics in Upland Cotton

A bacterial artificial chromosome （BAC） library was constructed for Gossypium hirsutum acc. TM-1, a genetic and genomic standard line for Upland cotton. The library consists of 147 456 clones with an average insert size of 122.8 kb ranging from 97 to 240 kb. About 96.0% of the clones have inserts over 100 kb. Therefore, this library represents theoretically 7.4 haploid genome equivalents based on an AD genome size of 2 425 Mb. Clones were stored in 384 384- well plates and arrayed into multiplex pools for rapid and reliable library screening. BAC screening was carried out by four-round poiymerase chain reactions using 23 simple sequence repeats （SSR） markers, three sequence-related amplified polymorphism markers and one pair of primers for a gene associated with fiber development to test the quality of the library. Correspondingly, in total 92 positive BAC clones were identified with an average four positive clones per SSR marker, ranging from one to eight hits. Additionally, since these SSR markers have been localized to chromosome 12 （A12） and 26 （D12） according to the genetic map, these BAC clones are expected to serve as seeds for the physical mapping of these two homologous chromosomes, sequentially map-based cloning of quantitative trait loci or genes associated with important agronomic traits.     

Construction of a Bacterial Artificial Chromosome Library of TM-1, a Standard Line for Genetics and Genomics in Upland Cotton

A bacterial artificial chromosome (BAC) library was constructed for Gossyplum hirsutum acc. TM-1, a genetic and genomic standard line for Upland cotton. The library consists of 147 456 clones with an average insert size of 122.8 kb ranging from 97 to 240 kb. About 96.0% of the clones have inserts over 100 kb. Therefore, this library represents theoretically 7.4 haploid genome equivalents based on an AD genome size of 2 425 Mb. Clones were stored in 384 384- well plates and arrayed into multiplex pools for rapid and reliable library screening. BAC screening was carded out by four-round polymerase chain reactions using 23 simple sequence repeats (SSR) markers, three sequence-related amplified polymorphism markers and one pair of pdmere for a gene associated with fiber development to test the quality of the library. Correspondingly, in total 92 positive BAC clones were Identified with an average four positive clones per SSR marker, ranging from one to eight hits. Additionally, since these SSR markers have been localized to chromosome 12 (A12) and 26 (D12) according to the genetic map, these BAC clonee are expected to serve as seeds for the physical mapping of these two homologous chromosomes, sequentially map-based cloning of quantitative trait loci or genes associated with Important agronomic traits.     

盐生野大豆的异黄酮积累及其生态学意义

以自然生长在盐碱地上的野大豆(Glycine soja)和不耐盐的栽培大豆(G. max)为材料,测定了它们在不同盐度条件下叶片、根部和种子的异黄酮含量,并测定了它们叶片的L-苯丙氨酸含量和苯丙氨酸裂解酶(PAL)活性,还测定了它们根部的结瘤量和固氮酶活性。通过两者比较,分析了它们的大豆异黄酮代谢和盐渍环境的关系。结果表明:盐渍处理不抑制盐生野大豆PAL酶的活性,其大豆异黄酮大量积累;相反,盐渍处理明显抑制栽培大豆PAL酶活性,其大豆异黄酮含量减少,而大豆异黄酮合成前体L-苯丙氨酸积累。结果还显示:在盐渍条件下,盐生野大豆根部异黄酮积累的同时,其根瘤结瘤量较多,且固氮酶活性也较高;而栽培大豆随着其根部异黄酮的减少,其根瘤结瘤量大大减少,且固氮活性大大下降。野大豆和栽培大豆的这些差别说明:盐生野大豆积累大豆异黄酮有其生态学意义,这很可能是野大豆通过异黄酮次生代谢途径适应盐渍环境的一种重要机制。     

Simple sequence repeat genetic linkage maps of A-genome diploid cotton (Gossypium arboreum)

This study introduces the construction of the first intraspacific genetic linkage map of the A-genome diploid cotton with newly developed simple sequence repeat (SSR) markers using 189 F2 plants derived from the cross of two Asiatic parents were detected using 6 092 pairs of SSR primers. Two-hundred and sixty-eight pairs of SSR pdmers with better polymorphisms were picked out to analyze the F2 population. In total, 320 polymorphic bands were generated and used to construct a linkage map with JoinMap3.0. Two-hundred and sixty-seven loci, Including three phenotypic traits were mapped at a logarithms of odds ratio (LOD) ≥ 3.0 on 13 linkage groups. The total length of the map was 2 508.71 cM, and the average distance between adjacent markers was 9.40 cM. Chromosome assignments were according to the association of linkages with our backbone tetraploid specific map using the 89 similar SSR loci. Comparisons among the 13 suites of orthologous linkage groups revealed that the A-genome chromosomes are largely collinear with the At and Dt sub-genome chromosomes. Chromosomes associated with inversions suggested that allopolyploidization was accompanied by homologous chromosomal rearrangement. The inter-chromosomal duplicated loci supply molecular evidence that the A-genome diploid Asiatic cotton is paleopolyploid.     

陆地棉洞A核雄性不育系及其MB保持系的遗传模式讨论

本文论述了陆地棉洞A核雄性不育系遗传的不同解释。根据洞A核雄性不育系以及它的不育保持系MB的遗传研究结果,证明洞A核雄性不育系受1对隐性核不育基因控制的结论是正确的,并提出了它的不育保持系MB的遗传本质。     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated co-transformation of multiple genes in upland cotton

Two cotton genotypes, Simian 3 (SM 3) and WC, were co-transformed using a mixture of four Agrobacterium tumefaciens cultures of strain LBA4404, each carrying a plasmid harboring the following genes, Bt + sck (for Bacillus thuringenesis protein and modified Cowpea trypsin inhibitor), bar (for glufosinate), keratin, and fibroin. The frequency of callus induction, embryogenesis, and plant regeneration were notably different between the two genotypes. However, there were no differences between the two genotypes for number of plantlets carrying multiple gene copies of different gene combinations as well as transformation frequency for different gene combinations. PCR analysis indicated that more than 80% of plantlets carried the nptII gene for kanamycin resistance. Overall, the co-transformation frequency of two or more genes was about 35%. Southern blot analysis confirmed integration of target genes into the cotton genome, and the number of copies of the transgene(s) varied from one to four. Multiple transgene expression was confirmed by RT-PCR analysis in some transgenic lines. Further analysis of T₁ plants demonstrated that multiple transgenes were inherited and expressed in progenies. Fei-Fei Li and Shen-Jie Wu are joint first authors.     

A genetic linkage map construction for sesame (Sesamum indicum L.)

Sesame (Sesamum indicum L.) is one of the oldest oilseed crops with high seed oil quality. The first sesame genetic linkage map based on F2 segregating population of an intraspecific cross between two cultivars was constructed. Using three types of PCR-based markers, 284 polymorphic loci including 10 EST-SSR marker, 30 AFLP marker and 244 RSAMPL marker, respectively, had been screened. Subsequently, a total of 220 molecular markers were mapped in 30 linkage groups covering a genetic length of 936.72 cM, and the average distance between markers was 4.93 cM. In this map, the linkage groups contained from 2 to 33 loci each and ranged in distance from 6.44 cM to 74.52 cM. Based on map information, sesame genome length was estimated to be approximately 1,232.53 cM, and genome coverage of this map was about 76.0%. As a starting point of sesame genome study, the genetic linkage map will be hopeful to tag traits of breeding interest and further aid in the sesame molecular breeding. Furthermore, RSAMPL marker had been also appreciated in this paper, for its first usage in genetic map construction and higher utilization potential in some crop species lacking much genome information.