四倍体马铃薯SSR遗传图谱的构建及晚疫病抗性QTL初步定位

利用四倍体马铃薯栽培种‘大西洋'和‘陇薯6号'杂交得到的190个F_1株系为作图群体,构建了四倍体马铃薯的分子遗传图谱,采用区间作图法对马铃薯晚疫病抗性进行了QTL初步定位。结果显示:通过对190个F_1株系进行检测,共发现有7个与晚疫病抗性相关的QTL位点,分别分布在第5、6、7、10和11连锁群上;各位点的LOD值在2.70~10.32之间,其中主效QTL位点3个(LOD≥3.5),可解释17.37%~65.68%的表型变异。获得紧密连锁的特异标记(S183-210、S148-460)为进一步进行QTL精确定位提供了参考。     

北方旱寒区冬油菜抗寒性相关指标的QTL定位

以抗寒性不同的白菜型冬油菜品种陇油7号与陇油9号为亲本构建的F2群体为材料,对白菜型冬油菜抗寒性相关的生理指标进行了QTL定位分析。在白菜型油菜的10条染色体上定位了SOD活性、POD活性、CAT活性、MDA含量、游离脯氨酸含量和可溶性蛋白含量共6个性状的24个QTL位点,可解释表型变异为11.1783%~81.1753%;10个显性效应表现为显性正效应,LOD值在3.2787~163.7958之间。染色体2A的Br ID90127-Br ID10421区、Br ID10421-Br ID10709区及Br ID10709-Br ID101165区,5A的BRMS034(R5)-Ra3-H10区、6A的Ra1-F06-Ra2-D04区、8A的Br ID10839-Ra2-E12区和10A的Br ID90115-Ra2-E07区是多个性状QTL共享的标记区间。研究结果对冬油菜抗寒性基因精确定位具有一定价值。     

水稻稻瘟病抗性QTL的定位分析

 稻瘟病是危害水稻最严重的病害之一。以抗稻瘟病的云南省地方品种魔王谷（MWG）和感稻瘟病的湖北省审定品种鄂晚8号（EW8）为亲本材料,构建双单倍体分离群体（DH）。利用22个菌株对亲本材料MWG/EW8进行致病性鉴定,从中筛选到5个毒性不同的鉴别菌株用于考察DH群体的稻瘟病抗性,构建包含120对SSR标记的分子遗传连锁图进行数量性状位点（QTL）的分析,鉴定出3个抗性QTL,均位于第6染色体长臂RM541附近, 3个QTL对抗病表型的贡献率介于7.7%~15.2 %之间,3个QTL的抗病等位基因均源自亲本MWG。     

甜玉米茎秆强度相关性状的数量性状基因座定位

为选育抗倒伏玉米品种,挖掘甜玉米茎秆强度相关性状的数量性状基因座（quantitative trait locus,QTL）,应用复合区间作图法以甜玉米组合T49×T56的F₂为作图群体,通过测定F_2：3家系的茎秆穿刺强度、茎秆抗压强度和茎秆弯折性能3个性状进行相关性状的QTL定位。结果表明,遗传连锁图谱包含153个SSR标记位点,覆盖玉米基因组1 199.1 cM,平均图距7.83 cM。3个性状共检测到10个QTL,其中与茎秆穿刺强度相关的2个QTL位于第3、7染色体上,解释11.81%和22.15%的表型变异,与茎秆抗压强度相关的4个QTL位于第1、3、7染色体上,单个QTL可解释3.68%~33.26%的表型变异,与茎秆弯折性能相关的4个QTL位于第3、6、8染色体上,单个QTL可解释3.55%~18.58%的表型变异。第7染色体检测到1个同时控制茎秆穿刺强度和茎秆抗压强度2个性状的QTL,位于umc1015~umc1987标记区间,分别可解释11.81%和33.26%的表型变异,第3染色体检测到1个同时控制茎秆穿刺强度、茎秆抗压强度、茎秆弯折性能3个性状的QTL,位于umc1400~dupssr23标记区间,分别可解释22.15%、13.27%和18.58%的表型变异。3个茎秆强度性状共同检测到的主效QTL,可在育种实践中用于分子标记辅助选择和抗倒伏玉米品种的选育。     

甜玉米小斑病抗性的遗传分析与主效QTL定位

为培育抗病品种,利用抗小斑病甜玉米自交系T14和感小斑病自交系T18为亲本配制杂交组合,对玉米抗小斑病性状进行遗传分析和抗病基因分子标记定位,用主基因＋多基因混合遗传模型和P₁、P₂、F₁、B₁、B₂、F₂ 6世代联合分析的方法对单位叶面积病斑数量进行遗传分析,并应用复合区间作图法检测抗小斑病QTL。结果表明,单位叶面积病斑数量受2对加性-显性-上位性主基因控制,自交系T14的抗病性在各个分离世代都以主基因遗传为主。在第4染色体上检测到4个相互连锁的小斑病抗性QTL,解释表型变异的7.7%、30.9%、14.8%和11.5%;在第6染色体上定位了1个抗病QTL,可解释表型变异的37.7%。检测到的小斑病抗性主效QTL位于第4和第6染色体的特征与2对主基因的遗传模型相吻合。     

干旱环境下油菜籽粒芥酸含量的QTL定位分析

为探讨干旱环境下冬油菜籽粒品质（脂肪酸含量和硫苷）分子遗传机理,以17NTS57（高芥酸）×CY12PXW-6-1（低芥酸）的衍生后代F₁、F₂、F_2∶3等群体为材料,结合天水和定西试点籽粒品质表型,进行干旱环境下籽粒芥酸的遗传定位及选择标记开发。结果表明：利用F_2∶3群体在两个试点共检测到油菜芥酸含量QTL位点7个,其中天水试点检测到4个,定西试点检测到3个。天水试点检测到2个主效QTL,即[STBX]qEATC08.2、qEATC09[STBZ],分别分布在C08、C09染色体,其表型贡献率在20%以上;[STBX]qEATA10（天水）和qEADA10[STBZ]（定西）被定位到A10染色体相同区间,在两个试点的表型贡献分别为10.42%和12.70%;[STBX]qEATC09和qEADC09[STBZ]被定位在C09染色体相同区间,两个试点的表型贡献率分别为20.00%和19.34%,为共定位主效QTL。3个QTL（[STBX]qEATC08.1（天水）、qEATC08.2（天水）、qEADC07（定西）[STBZ]）仅各在一个试点被检测到,其中2个微效修饰位点（[STBX]qEATC08.1和qEADC07[STBZ]）具有正向加性效应。在A10和C09染色体上定位的[STBX]qEA.A10和qEA.C09[STBZ]的主效QTL,这些标记可用于干旱条件下油菜籽粒芥酸含量改良的分子标记辅助选择。     

甘蓝型油菜蕾薹期抗旱相关性状的QTL分析

蕾薹期是甘蓝型油菜对干旱最为敏感的时期之一。以抗旱品系QY8-1和干旱敏感品种沪油16构建的含183个家系的F2∶3群体为研究材料,在现蕾至抽薹期进行干旱胁迫处理,正常灌溉为对照。结果表明,与对照相比,干旱胁迫后群体的抽薹高度、单株鲜重和叶片萎蔫指数平均下降了52.6%~55.3%,而且三个指标高度正相关。利用335个SRAP标记构建了一个长度为1661.9 c M的遗传图谱,通过复合区间作图法共检测到28个QTL,分布在14个连锁群上,可解释1.1%~36.6%的表型变异。其中,利用抽薹高度共检测到10个QTL,位于第15连锁群的q SH-D-5可解释36.6%的表型变异,为主效QTL。该区间还检测到其它3个QTL(q SH-DRI-1、q SH-D-5和q LWI-D-1),在抗旱分子标记辅助选择中应予以重点关注。同样,在第16连锁群(标记区间Em01/Me12-1—Em01Me09-1)也检测到4个重合的QTL,贡献率为1.1%~8.1%,为微效QTL。     

烟草赤星病菌嘧菌酯敏感与抗性菌株的代谢表型差异分析

 为了解烟草赤星病菌(Alternaria alternata)嘧菌酯抗性菌株与敏感菌株在代谢表型上的差异,采用Biolog代谢表型技术比较了抗性菌株(6-5和6-11)和敏感菌株(J6)的950种代谢表型。结果表明,抗性菌株和敏感菌株在代谢表型上基本一致,2个抗性菌株均不能代谢糖酵解中的氮源D-甘露糖胺,抗性菌株6-11还不能代谢尿素循环中的氮源L-鸟氨酸。烟草赤星病菌能代谢24.74%、85.26%、97.14%、89.83%的供试碳、氮、硫、磷源;具有广泛渗透压和pH适应能力;具有脱羧酶活性而无脱氨酶活性;能在高达10%氯化钠、6%氯化钾、5%硫酸钠、20%乙二醇、6%甲酸钠、6%尿素、12%乳酸钠、200 mmol·L^-1 磷酸钠、100 mmol·L^-1硫酸铵、100 mmol·L^-1硝酸钠和20 mmol·L^-1亚硝酸钠的渗透液中正常代谢,不能在20~200 mmol·L^-1的苯甲酸钠渗透液中代谢;其pH适应范围为3.5~10.0,最适约为6.0。研究结果有助于了解烟草赤星病菌的营养需求特性、渗透压和pH环境适应力,同时从代谢表型上揭示了赤星病菌对嘧菌酯抗性的潜在机理。     

南方根结线虫中国分离群体种内变异分析

为调查我国不同地区和不同寄主上的根结线虫Meloidogyne spp.种类分布以及群体变异情况,基于酯酶和苹果酸脱氢酶同工酶图谱及SCAR分子标记技术对2017—2019年从6省19种植物根部组织分离到的40个根结线虫群体进行鉴定,针对南方根结线虫M. incognita群体分别通过寄主鉴别法进行生理小种鉴别,利用携带Mi抗性基因的番茄进行毒力测试,对2龄幼虫的口针长度和体长进行测量,并对核糖体ITS和线粒体Nad5基因序列进行比较分析。结果显示:根结线虫分离群体经鉴定包括38个南方根结线虫群体和2个象耳豆根结线虫M. erterolobii群体;38个南方根结线虫群体中有35个群体被鉴别为1号生理小种,其余3个群体被鉴别为2号生理小种;发现1个南方根结线虫群体CN19可在携带Mi抗性基因的番茄上侵染繁殖,为毒性群体,其余群体无法进行侵染和繁殖,为无毒群体。南方根结线虫群体2龄幼虫的口针长度和体长均差异较大,而不同寄主来源分离群体的ITS和Nad5基因序列也存在一定变异。基于ITS和Nad5基因序列构建的系统发育树将所有根结线虫群体归为南方根结线虫和象耳豆根结线虫组成的2个独立分支,...     

应用RAPD方法获得与番茄ToMV抗性基因Tm2nv连锁的分子标记

 运用RAPD技术,在番茄ToMV抗性基因Tm2^nv的F₂代群体中采用混合分组分析法(bulkedse gregant analysis,BSA)进行分子标记研究,找到了一个与Tm2^nv基因连锁的分子标记OPD20₁₇₀₀,其遗传距离为7.067cM,LOD值为16.768。     

Evaluation and QTL mapping of resistance to powdery mildew in lettuce

Lettuce (Lactuca sativa) is the major leafy vegetable that is susceptible to powdery mildew disease under greenhouse and field conditions. Quantitative trait loci (QTLs) for resistance to powdery mildew under greenhouse conditions were mapped in an interspecific population derived from a cross between susceptible L. sativa cultivar Salinas and the highly susceptible L. serriola accession UC96US23. Four significant QTLs were detected on linkage groups LG 1 (pm‐1.1), LG 2 (pm‐2.1 and pm‐2.2) and LG 7 (pm‐7.1), each explaining between 35 to 42% of the phenotypic variation. The four QTLs are not located in the documented hotspots of lettuce resistance genes. Alleles for the disease resistance at the four QTLs originated from both parents (two from each), demonstrating that even highly susceptible accessions may provide alleles for resistance to powdery mildew. These QTLs appeared to operate during limited periods of time. Results of the field trials with F_2:3 and F_3:4 families derived from a Soraya (moderately resistant) × Salinas cross demonstrated effective transfer of resistance to powdery mildew in this material. An integrated rating approach was used to estimate relative levels of resistance in 80 cultivars and accessions tested in a total of 23 field and greenhouse experiments. Generally, very low resistance was observed in crisphead‐type lettuces, while the highest relative resistance was recorded in leaf and butterhead types. Comparison of two disease assessment methods (percentage rating and the area under the disease progress steps, AUDPS) for detection of QTLs shows that the two approaches complement each other.     

Genetic dissection of Lactuca saligna nonhost resistance to downy mildew at various lettuce developmental stages

This study used the pathosystem of lettuce ( Lactuca spp.) and downy mildew ( Bremia lactucae ) as a model to investigate the inheritance of nonhost resistance, and focused on the contribution of quantitative trait loci (QTLs) to nonhost resistance at various developmental stages in the lettuce life cycle. A set of 28 backcross inbred lines (BILs) of L. saligna CGN05271 (nonhost) introgressions in a L. sativa cv. Olof (host) background identified 16 introgressions that contributed to resistance at various plant developmental stages: seedlings, young plants, adult plants in the greenhouse and adult plants in the field. This paper provisionally considered these introgressions to be 16 QTLs. Of these 16 QTLs, seven were identified previously and nine were new. For 15 QTLs ( Rbq1, Rbq2, rbq3–7 and Rbq8–15 ), the resistance alleles were derived from the nonhost L. saligna ; the resistance allele of the other QTL ( Rbq16 ) was from the susceptible L. sativa cv. Olof. Of the 15 QTLs in L. saligna , only two, rbq5 and rbq7 , were found to be effective at every plant developmental stage; the other 13 QTLs were only effective at certain developmental stages. Experiments with seven B. lactucae races did not provide evidence that any QTL was race-specific. The data suggest that nonhost resistance in L. saligna is the result of cumulative effects of many resistance QTLs operating at various developmental stages.     

Genetic architecture of adult plant resistance to leaf rust in a wheat association mapping panel

Leaf rust caused by Puccina triticina is one of the most destructive fungal diseases of wheat (Triticum aestivum). Adult plant resistance (APR) is an effective strategy to achieve long‐term protection from the disease. In this study, findings are reported from a genome‐wide association study (GWAS) using a panel of 96 wheat cultivars genotyped with 874 Diversity Arrays Technology (DArT) markers and tested for adult leaf rust response in six field trials. A total of 13 quantitative trait loci (QTL) conferring APR to leaf rust were identified on chromosome arms 1BL, 1DS, 2AS, 2BL, 2DS, 3BS, 3BL, 4AL, 6BS (two), 7DS, 5BL/7BS and 6AL/6BS. Of these, seven QTLs mapped close to known resistance genes and QTLs, while the remaining six are novel and can be used as additional sources of resistance. Accessions with a greater number of combined QTLs for APR showed lower levels of disease severity, demonstrating additive and significant pyramiding effects. All QTLs had stable main effects and they did not exhibit a significant interaction with the experiments. These findings could help to achieve adequate levels of durable resistance through marker‐assisted selection and pyramiding resistance QTLs in local germplasm.     

Microsatellite markers for genes lr34/yr18 and other quantitative trait Loci for leaf rust and stripe rust resistance in bread wheat

ABSTRACT Leaf rust and stripe rust, caused by Puccinia triticina and P. striiformis, respectively, are important diseases of wheat in many countries. In this study we sought to identify molecular markers for adult plant resistance genes that could aid in incorporating such durable resistance into wheat. We used a doubled haploid population from a Japanese cv. Fukuho-komugi x Israeli wheat Oligoculm cross that had segregated for resistance to leaf rust and stripe rust in field trials. Joint and/or single-year analyses by composite interval mapping identified two quantitative trait loci (QTL) that reduced leaf rust severity and up to 11 and 7 QTLs that might have influenced stripe rust severity and infection type, respectively. Four common QTLs reduced stripe rust severity and infection type. Except for a QTL on chromosome 7DS, no common QTL for leaf rust and stripe rust was detected. QTL-7DS derived from 'Fukuho-komugi' had the largest effect on both leaf rust and stripe rust severities, possibly due to linked resistance genes Lr34/Yr18. The microsatellite locus Xgwm295.1, located almost at the peak of the likelihood ratio contours for both leaf and stripe rust severity, was closest to Lr34/Yr18. QTLs located on 1BL for leaf rust severity and 3BS for stripe rust infection type were derived from 'Oligoculm' and considered to be due to genes Lr46 and Yr30, respectively. Most of the remaining QTLs for stripe rust severity or infection type had smaller effects. Our results indicate there is significant diversity for genes that have minor effects on stripe rust resistance, and that successful detection of these QTLs by molecular markers should be helpful both for characterizing wheat genotypes effectively and combining such resistance genes.     

小麦抗条锈病一致性数量性状位点(MQTL)图谱构建

 小麦条锈病是造成小麦减产和品质劣化的最重要病害,定位小麦染色体上一致性条锈病抗性基因/位点/区段是小麦条锈病抗性分子育种的重要基础。本研究对至今分子标记和遗传定位的342个条锈病抗性基因/位点/区段进行数据搜集整理,借助Maccaferr和Andrzej的参考图谱,基于元分析技术进行Meta-QTL(MQTL)检测,共获得194个小麦抗条锈病MQTL,包括74个与严重度(Disease severity, DS)相关,46个与反应型(Infection type, IT)相关、19个与病程曲线下面积相关(Area under disease progress curve, AUDPC)、28个与DS和IT共相关、6个与DS和AUDPC共相关、15个与IT和AUDPC共相关、6个与其他条锈病抗性性状相关。这些抗条锈病一致性QTL定位于小麦21条染色体上,呈非均匀分布,且部分MQTL集中成簇。通过与已发表的正式命名抗条锈病基因比较分析,发现大多数正式命名基因定位于MQTL簇区段,说明这些MQTL簇区段很可能是控制小麦条锈病抗性热点区域。控制小麦抗条锈病一致性QTL遗传图谱的构建为小麦条锈病抗性基因精细定位及抗病育种提供了遗传信息参考依据。     

小麦抗条锈病一致性数量性状位点(MQTL)图谱构建

 小麦条锈病是造成小麦减产和品质劣化的最重要病害,定位小麦染色体上一致性条锈病抗性基因/位点/区段是小麦条锈病抗性分子育种的重要基础。本研究对至今分子标记和遗传定位的342个条锈病抗性基因/位点/区段进行数据搜集整理,借助Maccaferr和Andrzej的参考图谱,基于元分析技术进行Meta-QTL(MQTL)检测,共获得194个小麦抗条锈病MQTL,包括74个与严重度(Disease severity, DS)相关,46个与反应型(Infection type, IT)相关、19个与病程曲线下面积相关(Area under disease progress curve, AUDPC)、28个与DS和IT共相关、6个与DS和AUDPC共相关、15个与IT和AUDPC共相关、6个与其他条锈病抗性性状相关。这些抗条锈病一致性QTL定位于小麦21条染色体上,呈非均匀分布,且部分MQTL集中成簇。通过与已发表的正式命名抗条锈病基因比较分析,发现大多数正式命名基因定位于MQTL簇区段,说明这些MQTL簇区段很可能是控制小麦条锈病抗性热点区域。控制小麦抗条锈病一致性QTL遗传图谱的构建为小麦条锈病抗性基因精细定位及抗病育种提供了遗传信息参考依据。     

Quantitative trait loci associated with isolate specific and isolate nonspecific partial resistance to Phoma macdonaldii in sunflower

Black stem, caused by Phoma macdonaldii , is one of the most important diseases of sunflower in the world. Quantitative trait loci (QTLs) implicated in partial resistance to two single pycnidiospore isolates of P. macdonaldii (MP8 and MP10) were investigated using 99 recombinant inbred lines (RILs) from the cross between sunflower parental lines PAC2 and RHA266. The experimental design was a randomized complete block with three replications. High genetic variability and transgressive segregation were observed among RILs for partial resistance to P. macdonaldii isolates. QTL-mapping was performed using a recently developed high-density SSR/AFLP sunflower linkage map. A total of 10 QTLs were detected for black stem resistance. The phenotypic variance explained by each QTL (R²) was moderate, ranging from 6 to 20%. Four QTLs were common between two isolates on linkage group 5 and 15 whereas the others were specific for each isolate. Regarding isolate-specific and isolate-nonspecific QTLs detected for partial resistance, it is evident that both genetic effects control partial resistance to the disease isolates. This confirms the need to consider different isolates in the black stem resistance breeding programmes. The four SSR markers HA3700, SSU25, ORS1097 and ORS523_1 encompassing the QTLs for partial resistance to black stem isolates could be good candidates for marker assisted selection.     

Main effects, epistasis, and environmental interactions of quantitative trait Loci for fusarium head blight resistance in a recombinant inbred population

ABSTRACT Chinese Spring Sumai 3 chromosome 7A disomic substitution line (CS-SM3-7ADS) is highly resistant to Fusarium head blight (FHB), and an F(7) population of recombinant inbred lines derived from the cross CS-SM3-7ADS x Annong 8455 was evaluated for resistance to FHB to investigate main effects, epistasis, and environmental interactions of quantitative trait loci (QTLs) for FHB resistance. A molecular linkage map consists of 501 simple sequence repeat and amplified fragment length polymorphism markers. A total of 10 QTLs were identified with significant main effects on the FHB resistance using MapQTL and QTLMapper software. Among them, CS-SM3-7ADS carries FHB-resistance alleles at five QTLs on chromosomes 2D, 3B, 4D, and 6A. One QTL on 3BS had the largest effect and explained 30.2% of the phenotypic variance. Susceptible QTLs were detected on chromosomes 1A, 1D, 4A, and 4B. A QTL for enhanced FHB resistance was not detected on chromosome 7A of CS-SM3-7ADS; therefore, the increased FHB resistance in CS-SM3-7ADS was not due to any major FHB-resistance QTL on 7A of Sumai 3, but more likely was due to removal of susceptible alleles of QTLs on 7A of Chinese Spring. QTLMapper detected nine pairs of additive-additive interactions at 17 loci that explained 26% phenotypic variance. QTL-environment interactions explained 49% of phenotypic variation, indicating that the environments significantly affected the expression of the QTLs, especially these epistasis QTLs. Adding FHB-enhancing QTLs or removal of susceptible QTLs both may significantly enhance the degree of wheat resistance to FHB in a wheat cultivar.     

Consistent action of two partially effective loci conferring resistance to Globodera pallida Pa2/3 across multiple nematode field populations

The potato cyst nematodes (PCN) Globodera rostochiensis and Globodera pallida are significant pests of potatoes worldwide. The most effective control methods are crop rotation and the deployment of resistant varieties. Complete resistance to G. rostochiensis based on a single resistance gene has successfully been integrated into many varieties. However, resistance to G. pallida has not been as successful to date, with current varieties only exhibiting partial resistance. Combining partially effective quantitative trait loci (QTLs) for resistance can increase the strength and breadth of the resistance. An additive effect on resistance has previously been demonstrated on combining two QTLs from Solanum tuberosum subsp. andigena (GpaIV^s_adg) and Solanum vernei (Gpa5). However, populations of G. pallida can be quite divergent and it was unclear whether the relative effects of the individual QTLs and the combined additive effect would be consistent across different G. pallida Pa2/3 populations. Using a mapping population segregating for both QTLs, the effect of the QTLs individually and combined was examined on four UK‐derived field populations of G. pallida pathotype Pa2/3, and the relative effects of the individual QTLs and the additive effect of the combination found to be consistent across all populations.     

Novel septoria speckled leaf blotch resistance loci in a barley doubled-haploid population

The genetics of resistance to Septoria speckled leaf blotch (SSLB), caused by Septoria passerinii, was studied in the Leger × CIho9831 barley doubled-haploid population. The 140 lines in the population segregated as 102 resistant and 38 susceptible, approximating a 3:1 ratio. A recombination map was developed using diversity arrays technology and other molecular markers. Quantitative trait locus (QTL) analysis demonstrated that resistance is primarily conferred either by having the CIho9831 allele at a QTL on 6HS or by having the CIho9831 allele at both of two QTLs on 3H and 2HL. In addition, ≈1/16 of the lines were resistant for unidentified reasons. This model predicts a resistant/susceptible ratio of 11:5, which fits the phenotypic observations. Minor QTLs were detected on 2HS and 1H. DNA sequences of linked markers suggest that the 6HS, 3H, and 2HS QTLs are part of resistance gene clusters and that the 6HS and 3H QTLs share homology. The 6HS QTL is identical to or closely linked to the SSLB resistance locus Rsp4 and the 1H QTL to the Rsp2 or Rsp3 locus. The 3H and 2HS QTLs are unique and offer new opportunities for pyramiding resistance genes through marker-assisted breeding for resistance to S. passerinii.