Identification of AFLP Markers Linked to Lr19 Resistance to Wheat Leaf Rust

AFLP analyses were carried out on Thatcher, 23 near-isogenic lines and F2 generation of TcLrl9 × Thatcher, to develop molecular markers for gene Lr19 resistance to wheat leaf rust. Seven markers linked to Lr19 resistance trait were obtained,which were P-AGT/M-GAG289 bp (3.3 cM), P-ACA/M-GGT102 bp (4.1 cM), P-ACA/M-GGT106 bp (4.1 cM), P-AAC/M-CAG123 bp(4.9 cM), P-AAC/M-GGT203 bp (5.0 cM), P-ACA/M-GGT290 bp (5.7 cM), and P-ATC/M-GAG293 bp (9.6 cM). All of these specific fragments were isolated from the polyacrylamide gels, reamplified, cloned, and sequenced. The research may facilitate genetic mapping, physical mapping, and the eventual cloning of Lr19.     

小麦抗叶锈病基因Lr45的AFLP分子标记

 利用AFLP技术对小麦抗叶锈基因Lr45进行了标记，从60对AFLP引物中筛选出2对在亲本及TcLr45×Thatcher F2抗感群体间揭示多态性的引物P-AGG/M-GAG和P-ACA/M-GGT。其扩增片段为261 bp和105 bp，2个标记与Lr45的遗传距离分别为0.6 cM和1.3 cM。测序比较261 bp片段与大麦属Vulgare HotrI基因部分序列同源性达86%，105 bp片段与一粒小麦磷脂酰丝氨酸脱羧酶基因部分序列同源性高达96%。2个测序片段均包含开放阅读框（ORF）序列。     

小麦抗叶锈病基因Lr19 的SSR标记

 选取小麦感叶锈病亲本Thatcher、6个以Thatcher为遗传背景的小麦抗叶锈近等基因系及TcLr19与Thatcher杂交F2代为材料，开展了小麦抗叶锈基因Lr19的微卫星分子标记研究；从13对微卫星引物中筛选出了1对在亲本及TcLr19×Thatcher F2抗感群体间揭示多态性的引物Xgwm44，并获得了1个与小麦抗叶锈基因Lr19紧密连锁的SSR标记Xgwm44139bp，此标记位点与Lr19基因之间的遗传距离为0.9cM。该研究可为分子标记辅助育种及构建遗传图谱、物理图谱和基因克隆奠定了基础。     

小麦抗叶锈近等基因系TcLr38的SRAP-SSR(eSSR)分析

小麦抗叶锈基因Lr38在我国高抗叶锈病,直到目前该基因的分子标记开发较少,开发其分子标记对于该基因的研究与利用具有重要意义。利用594对SRAP-SSR(eSSR)引物组合对以Thatcher为背景小麦抗叶锈近等基因系材料TcLr38和Thatcher进行PCR扩增。引物组合ARBI8-Xcwem8R和ARBI2-Xgwm497F在TcLr38中分别扩增出300和400bp多态性条带。利用47个小麦抗叶锈近等基因系进一步检测,引物ARBI8-Xcwem8R仅在TcLr38中扩增出特异条带。经TcLr38×Thatcher F2代分离群体验证,该标记与Lr38遗传距离较远。对该片段克隆测序,片段长度为277bp,BLAST比对与GenBank中所收录序列无相似性,该片段为与Lr38相关的新的序列。     

小麦抗叶锈基因Lr45的SCAR标记

 【目的】建立小麦抗叶锈基因Lr45 SCAR（sequenced characterized amplified region序列特征扩增区域）标记。【方法】以小麦抗叶锈病基因材料TcLr45和感病材料Thatcher为亲本,利用黑麦基因组特异的RAPD标记引物OPH20进行PCR扩增,对获得的与预期大小相同的1.5kb的特异片段进行克隆测序,并根据该序列设计一对特异PCR引物LRYR和LRYF,对TcLr45×Thatcher F2代单株构建的分离群体进行扩增,验证该标记与Lr45的连锁关系,Mapmaker 3.0软件绘制遗传连锁图。【结果】该标记在TcLr45中扩增出单一条带,片段大小为1 272 bp（命名为Ypsc20H1272）,而在感病亲本中则无扩增条带。F2代分离群体进行连锁分析,遗传距离为8.2 cM,该标记为与Lr45连锁的SCAR标记。【结论】将Lr45的RAPD标记转化成SCAR标记。     

小麦抗叶锈病基因Lr24的TRAP分析

 【目的】获得与Lr24基因紧密连锁并可能作为探针的TRAP分子标记。【方法】应用TRAP技术,选用90对引物组合对小麦抗叶锈病基因Lr24、感病亲本Thatcher及其F2代抗感各10株组成的抗、感基因池（Br、Bs）的扩增带型差异进行分析,用筛选获得的多态性引物对TcLr24×Thatcher F2群体进一步筛选,进而用获得的特异引物对45个小麦抗叶锈病近等基因系和30个小麦二倍体材料进行分析。【结果】获得10对能够在TcLr24、Br与Thatcher、Bs间产生多态性的引物,多态性引物检出率为11.11%。其中1对在F2抗感群体中有差异且稳定扩增的TRAP引物ARBI1/RGA-2F,其161bp 扩增产物仅在F2抗病单株中出现,感病单株中缺失。用该引物对45个近等基因系和30个二倍体材料检测发现,近等基因系TcLr19、TcLr29、TcLr38、Lr42和TcLr44中有相同大小片段的扩增产物,30个二倍体材料中未出现相应扩增产物。【结论】本研究获得的一个与Lr24紧密连锁的TRAP标记,该标记可筛选含有Lr24基因的育种后代群体,可作为探针用于文库的筛选。     

小麦抗叶锈基因Lr37 ISSR分子标记的初步研究

利用ISSR(内部简单重复序列)技术对感病品种Thatcher及20个以Thatcher为轮回亲本的小麦抗叶锈病近等基因系进行分析,找到1个与Lr37基因连锁的ISSR标记。经过多次重复发现,在一套ISSR引物中,引物UBC812在小麦抗叶锈基因Lr37近等基因系间表现多态性。当用这个引物对已知含Lr37基因的3个抗病材料及其它不含Lr37基因的感病材料进行检测时,多态性标记UBC812-1200可以从3个含Lr37基因的抗病材料中检测到1条1200bp的多态性带,而在其它感病材料中均未出现。     

周麦11、西农1163-4抗叶锈病基因与周8425B中LrZH84的关系

为了明确周麦11、西农1163-4抗叶锈病基因与周8425B中Lr ZH84的关系,用叶锈菌小种THTT接种周麦11/中国春的145个F2单株,而另一叶锈菌生理小种FHTT分别接种周麦11/中国春的285个F2单株、西农1163-4/Thatcher的232个F2单株;2个与Lr ZH84紧密连锁的标记gwm582、ω-secalin/Glu-B3用于检测3个群体中是否携带抗叶锈病基因Lr ZH84。结果显示:周麦11对叶锈菌生理小种THTT的抗性由2个显性抗病基因控制,经标记检测发现,周麦11中1个抗病基因是Lr ZH84,另1个抗叶锈病基因为未知基因;周麦11对叶锈菌生理小种FHTT的抗性由单基因控制,标记检测发现该基因不同于Lr ZH84,为未知抗叶锈病基因;西农1163-4对叶锈菌生理小种FHTT的抗性由单基因控制,分子标记检测结果表明,该基因可能为Lr Xi,由于Lr ZH84对FHTT表现感病,表明Lr Xi不同于Lr ZH84。通过研究证实,周麦11中含有Lr ZH84和1个未知的抗叶锈病基因,西农1163-4中的抗叶锈病基因Lr Xi与Lr ZH84不同;同时,周麦11、西农1163-4中可能还含有其他抗病基因,有待进一步研究。研究将为抗病基因聚合、基因布局、培育抗病新品种奠定理论基础。     

春小麦品种川育19抗叶锈性遗传分析

对春小麦品种川育19的抗叶锈性进行了遗传分析,以期为小麦抗叶锈病育种提供理论指导。作为父本,川育19分别与感病品种Thatcher及小麦抗叶锈病近等基因系Lr1和Lr3的载体品系Tc*6/Centenario和Tc*6/Democrat杂交,获得F_1、F_2、F_3后,分别在苗期和成株期进行抗病性测定。在苗期,接种致病类型BGD/HL,Thatcher×川育19杂交组合的F_2符合15(抗病)∶1(感病)的分离比例,而其余2个杂交组合的F_2均全部抗病,说明川育19含有显性遗传的抗叶锈病基因Lr1和Lr3,并相互独立控制对致病类型BDG/HL的抗病性;接种致病类型FBC/GN(或SHJ/GL),Thatcher×川育19杂交组合的F_2符合3(抗病)∶1(感病)的分离比例,而Tc*6/Centenario(Lr1)×川育19[或Tc*6/Democrat(Lr3)×川育19]杂交组合的F_2全部抗病,说明川育19含有呈显性遗传的抗叶锈病基因Lr1(或Lr3)且控制对致病类型FBC/GN(或SHJ/GL)的抗病性。在成株期,上述3个杂交组合的F_2均符合9(抗病)∶7(感病)的分离比例,说明川育19的成株期抗病性由2对互补遗传的显性抗叶锈病基因控制,且Lr1和Lr3在成株期不起作用。     

小麦抗叶锈基因Lr38的一个新标记

【目的】建立小麦抗叶锈近等基因系材料TcLr38特异的PCR标记。【方法】以Thatcher为对照,以TcLr38和TcLr38×Thatcher F2代单株构建的分离群体为材料,利用TcLr38远缘亲本中间偃麦草特异的SCAR标记引物进行PCR扩增获得单一条带,并以50个小麦抗叶锈近等基因系材料对该标记特异性进行检测,Mapmaker 3.0软件计算该标记与Lr38的遗传连锁距离。【结果】中间偃麦草特异的SCAR标记引物在TcLr38中获得单一扩增片段大小为982 bp,50个小麦抗叶锈近等基因系检测表明为TcLr38的特有条带,F2代分离群体验证表明为与Lr38共分离的分子标记,命名为Y38SCAR982。【结论】Y38SCAR982可以作为Lr38的分子标记,并证实该基因由中间偃麦草向普通小麦转移的事实。     

Molecular Markers for Leaf Rust Resistance Gene Lr45 in Wheat Based on AFLP Analysis

Amplified fragment length polymorphism (AFLP) analysis was carried out in Thatcher, near isogenic lines (NILs) carrying different genes conferring resistance against wheat leaf rust, and TcLr45 x Thatcher F₂ progenies were used to develop markers for Lr45 gene. Sixty AFLP primer combinations were screened and most of them provided clear amplification products, 31 primer combinations displayed polymorphism of TcLr45 in 23 NILs. Two AFLP markers closely linked to the gene Lr45 were acquired: P-AGG/M-GAG_{261 bp}, which was found closely linked to the Lr45 locus at a distance of 0.6 cM on one side, and P-ACA/M-GGT_{105 bp}, which was found at a distance of 1.3 cM on the other side. The specific bands were cloned and subsequently sequenced. The 261-bp fragment produced by P-AGG/M-GAG showed 86% similarity with the sequence of Vulgare Hart I gene; the 105-bp fragment produced by P-ACA/M-GGT showed 96% similarity with the phosphatidylserine decarboxylase gene of the Triticum monococcum. Both included an open reading frame (ORF).     

A SSR Marker for Leaf Rust Resistance Gene Lr19 in Wheat

Microsatellite was carded out in Thatcher, six near-isogenic lines and F2 progeny of TcLr19xThatcher to develop molecular markers for leaf rust resistance gene Lr19. Thirteen primer pairs were screened, of which one primer pair Xgwm44 displayed polymorphsim in the population of TcLr 19, Thatcher, and their F2 generations. One marker closed linked to Lr19 resistance trait was obtained, and was named Xgwm44139bp with the genetic distance 0.9 cM. The research shows that Lr19 has more potential in marker-assisted breeding programs in wheat and provides a step stone for mapping genetic map, physical map and the eventual cloning.     

小麦抗叶锈基因Lr44的AFLP分子标记

利用AFLP技术借助于小麦抗叶锈近等基因系和TcLr44×ThatcherF2代分离群体材料,获得4个Lr44的分子标记,分别为Paag:Mcta300,Paac:Mcgt85,Paag:Mcta395和Paac:Mcgt90,与目的基因的遗传距离分别为0 01cM、1 1cM、3cM、2 2cM和2 8cM,为分子辅助育种、构建密集的遗传图谱、克隆Lr44以及研究基因编码特性等奠定基础。     

两个中国小麦品种中抗叶锈基因的遗传分析和基因定位

【目的】确定来自四川的两个小麦品种绵阳351-15和SW8588所携带的抗叶锈基因,为选育持久抗锈品种提供理论依据。【方法】在苗期用15个叶锈菌生理小种接种小麦品种绵阳351-15、SW8588和30个含有已知抗叶锈基因的近等基因系,推导2个材料中所含有的抗叶锈病基因,同时以小麦抗叶锈品种绵阳351-15和SW8588分别同感病品种郑州5389杂交获得F1和F2代群体,用叶锈菌小种FHTT接种各亲本及其杂交后代,进行抗叶锈遗传分析,并利用SSR和STS标记进行抗叶锈病基因的分子定位。【结果】经苗期基因推导发现SW8588中含有未知基因不同于已知抗叶锈病基因Lr1,绵阳351-15中可能含有已知抗叶锈病基因Lr1。用叶锈菌小种FHTT接种各F1和F2代群体,2个F2代群体抗感单株分离比例均符合3﹕1的理论分离比例,表明2个亲本对小种FHTT的抗病性均由1个显性基因控制。经过分子标记分析,在小麦材料绵阳351-15中发现该抗叶锈基因与位于5DL的SSR标记barc144和wmc765连锁,其遗传距离分别为8.9和20.8 cM,并同Lr1的STS标记WR003共分离,确定在小麦材料绵阳351-15中对小种FHTT的抗病性由抗叶锈基因Lr1提供;经分子标记检测SW8588中含有1对显性的抗叶锈病基因,暂命名为LrSW85,该基因位于5DL染色体上与Lr1的STS标记WR003共分离,该抗叶锈基因可能是Lr1的等位基因或紧密连锁基因。【结论】通过基因推导、遗传分析和分子标记等手段,确定小麦材料绵阳351-15中含有抗叶锈基因Lr1;小麦材料SW8588中含有抗叶锈基因LrSW85,该基因可能为Lr1的等位基因或紧密连锁基因。     

Identification of <Emphasis Type="Italic">Lr24</Emphasis> with targeted region amplified polymorphism (TRAP) analysis in wheat

This research is aimed at developing TRAP markers, as a probe for library screening, closely linked to or co-segregated with Lr24. Ninety TRAP primer pairs were used to test the resistant and susceptible parents, as well as the resistant bulk and the susceptible bulk in our study. The polymorphic TRAP primers of TcLr24 were employed to genotype the F₂ population from TcLr24×Thatcher subsequently. Ten of 90 TRAP primer pairs displayed polymorphism between TcLr24 and Thatcher, accounting for 11.11%. A further study found that primer ARBI1/RGA-2F generated a 161 bp fragment presented only in the resistance plants of F₂ population. Forty-five other wheat leaf rust resistant NILs and 30 diploid materials of wheat were also tested to detect the specificity of the primer. This specific band was amplified in TcLr19, TcLr29, TcLr38, TcLr42 and TcLr44, but absented in all the 30 diploid materials. It was concluded that this marker ARBI1/RGA-2F was closely linked to Lr24, which could be used to detect Lr24 in the F₂ population of TcLr24×Thatcher, and be further used as a probe for cDNA and BAC library screening of TcLr24.