小麦叶锈病是危害小麦最严重的病害之一，该病由小麦叶锈菌（Puccinia recondite f. sp. tritici）引起，侵染小麦叶片，严重影响小麦光合作用从而造成减产，培育和利用小麦抗叶锈病品种是最为经济有效的防治措施。为鉴定国内外普通小麦材料中所携带的抗病基因并了解其组成背景，发掘新的抗叶锈病基因，本研究结合基因推导、分子标记检测等方法对66个来自世界不同国家的普通小麦品种（系）进行了抗叶锈病基因鉴定。在苗期接种17个不同毒力的小麦叶锈菌生理小种，通过与36个含有单个已知抗病基因的载体品种抗性比较进行基因推导。同时，利用12个与已知抗病基因紧密连锁的分子标记对供试品种（系）进行基因标记检测，以验证基因推导结果。在河南周口（2016-2017年度）、河北保定（2017-2018年度）两地对66个供试品种（系）进行小麦叶锈病田间叶锈抗性调查，利用SAS软件对鉴定数据进行分析，以筛选出具有成株慢锈性的品种。结果表明，在66个供试品种（系）中，12个品种（系）含有Lr1，4个品种（系）含有Lr26，3个品种含有Lr10，2个品种含有Lr20，2个品种含有Lr17。通过成株抗病基因分子标记检测发现，14个品种（系）含有Lr34，5个品种含有Lr46，3个品种（系）含有Lr37。结合田间调查结果发现，有17个品种（系）具有成株慢锈性。这些含有已知抗病基因的品种及慢锈性品种将丰富我国现有的小麦种质资源，有利于培育抗病品种，同时为利用基因布局防治小麦叶锈病提供遗传学依据。

Wheat leaf rust is a destructive foliar disease of common wheat (Triticum aestivum L.) worldwide. The most effective, economical s to control the disease is growing resistant cultivars with adult plant resistance (APR). The Chinese wheat lines W014204 and Fuyu 3 showed high leaf rust resistance in the field. To identify leaf rust APR genes in the two lines, two mapping populations with 215 and 163 F2:3 lines from the crosses W014204/Zhengzhou 5389 and Fuyu 3/Zhengzhou 5389, respectively, were phenotyped for leaf rust severities during the 2010–2011, 2011–2012 and 2012–2013 cropping seasons in the field at Baoding, Hebei Province, China. A total of 1 215 SSR markers were used to identify the quantitative trait loci (QTLs) for leaf rust APR in the two populations. In the W014204/Zhengzhou 5389 population, three QTLs were detected and designated as QLr.hbu-1BL.1, QLr.hbu-2BS.1 and QLr.hbu-7DS, and explained 2.9–8.4, 11.5–38.3 and 8.5–44.5% of the phenotypic variance, respectively; all the resistance alleles at these loci were derived from W014204. In the Fuyu 3/Zhengzhou 5389 population, three QTLs, QLr.hbu-1BL.2, QLr.hbu-2BS.2 and QLr.hbu-7BL, explained 12.0–19.2, 22.3–38.9 and 4.1–4.3% of the phenotypic variance, respectively, and all resistance alleles were contributed by Fuyu 3. Based on chromosome positions of closely linked markers, both QLr.hbu-1BL.1 and QLr.hbu-1BL.2 are Lr46, and QLr.hbu-7DS is Lr34. QLr.hbu-7BL was mapped on chromosome 7BL near to Lr68 and they are likely the same gene. Based on chromosome positions, pedigree and field reactions, the two 2BS QTLs are different from all the known APR genes and are likely to be new APR QTL for leaf rust. These QTLs and their closely linked markers are potentially useful for improving leaf rust resistance in wheat breeding.

The Chinese wheat line Yu 356-9 exhibits a high level of resistance to leaf rust. In order to decipher the genetic base of resistance in Yu 356-9, gene postulation, inheritance analyses, and chromosome linkage mapping were carried out. Gene postulation completed using 15 leaf rust pathotypes and 36 isogenic lines indicated that Yu 356-9 was resistant to all pathotypes tested. F1 and F2 plants from the cross Yu 356-9 (resistant)/Zhengzhou 5389 (susceptible) were tested with leaf rust pathotype “FHNQ” in the greenhouse. Results indicated a 3:1 segregation ratio, indicative of the presence of a single dominant leaf rust resistance gene in Yu 356-9 which was temporarily designated as LrYu. Bulk segregant analysis and molecular marker assays were used to map LrYu. Five simple sequence repeat (SSR) markers on chromosome 2BS were found closely linked to LrYu. Among these markers, Xwmc770 is the most closely linked, with a genetic distance of 5.7 cM.

To detect the leaf rust resistance genes in the 7 Chinese spring wheat clultivars Shenmian 99025, Shenmia 99042, Shenmian 85, Shenmian 91, Shenmian 96, Shenmian 1167 and Shenmian 962, Thatcher, Thatcher backgrounded near-isogenic lines and 15 pathotypes of P. triticina were used for gene postulate at the seedling stage, and 9 of the 15 pathotypes were used in the field tests. Molecular markers closely linked to, or co-segregated with resistance genes Lr1, Lr9, Lr10, Lr19, Lr20, Lr21, Lr24, Lr26, Lr28, Lr29, Lr32, Lr34, Lr35, Lr37, Lr38, and Lr47 were screened to assist detection of the resistance genes. As results, 4 known resistance genes, including Lr1, Lr9, Lr26, and Lr34, and other unknown resistance genes were postulated singly or in combination in the tested cultivars. Shenmian 85, Shenmian 91, Shenmian 96, Shenmian 962, Shenmian 1167, and Shenmian 99042 are potentially useful for wheat production and breeding programs. The result suggested that combining gene postulation, molecular markers and pedigrees is effective and more accuracy method to know the resistance genes in cultivars.

One resistance gene analog fragment named RGA-CIN14 was isolated from TcLr19 wheat, which contains kinase-2,kinase-3a, and the GLPL motif of the NBS-spanning region, using degenerated primers according to the nucleotidebinding site (NBS) conserved domain. Based on the RGA-CIN14, a full-length cDNA, CIN14, which was 2 987 bpencoding 880 amino acids, was obtained by using the method of the rapid amplification cDNA ends (RACE). Bioinformaticsanalysis showed that the deduced amino acids of CIN14 protein consisted of a NB-ARC conserved domain and manyleucine-rich repeats (LRR) domains. The phylogenetic tree analysis indicated a considerable identity of the proteinencoded by CIN14 with that of wheat leaf rust resistance gene Lr1, but a lower similarity with Lr21. The expression profileof the CIN14 gene detected by semi-quantitative RT-PCR showed that the CIN14 gene was not induced by Pucciniatriticina and it was a constitutive gene with low abundance in the wheat leaf tissue. The resistance homology sequencewas successfully obtained, which provides the shortcut for cloning of the resistance gene in TcLr19 wheat.

This research was aimed to develop AFLP markers co-segregated with gene Lr24 and validate the using for marker assisted selection (MAS). An F2 population developed from the cross between the resistant line TcLr24 and the susceptible line Thatcher was tested for resistance to the Puccinia triticina races BGQQ and SHRT using for genetic analysis and molecular marker. A total of 224 AFLP primer combinations were used to test the resistant and susceptible parents, as well as the resistant bulk and the susceptible bulk. Four AFLP markers, P-AGA/M-CTT289 bp, P-AGC/M-CAC188 bp, P-AGC/MCAC 162 bp, and P-ACG/M-CGC239 bp, were co-segregated with Lr24. The AFLP fragment from the primer combination PACG/ M-CGC was cloned, sequenced and converted into a STS marker named as ASTS212. Thatcher backgrounded NILs and 115 varieties were examined by using this STS marker and the marker SCS1302607 developed by Gupta. 5R615, 5R616, 1R13, and 1R17 were identified and validated to contain gene Lr24. The marker is dominant and may be useful in identification the resistance gene Lr24 in wheat and wheat breeding programs.

Virus-induced gene silencing (VIGS) offers a rapid and high throughout technology platform for the analysis of gene function in plants. The barley stripe mosaic virus (BSMV) VIGS system was optimized in studies silencing phytoene desaturase expression in wheat, and demonstrated that infection with BSMV construct carrying a 412 bp fragment of TaRAR1 caused conversion of incompatible to compatible interactions to Lr24-mediated resistance in wheat TcLr24 and cultivar 5R615 harboring Lr24 whereas infection with a control construct had no effect on resistance or susceptibility. RTPCR analysis showed that BSMV-induced gene silencing could be detected at mRNA levels. These studies indicated that TaRAR1 was a required component for Lr24-mediated race-specific resistance and the BSMV-VIGS was a powerful tool for dissecting the genetic pathways of disease resistance in hexaploid wheat.