Meta-QTL analysis for mining of candidate genes and constitutive gene network development for fungal disease resistance in maize(Zea mays L.)

The development of resistant maize cultivars is the most effective and sustainable approach to combat fungal diseases.Over the last three decades,many quantitative trait loci(QTL)mapping studies reported numerous QTL for fungal disease resistance(FDR)in maize.However,different genetic backgrounds of germplasm and differing QTL analysis algorithms limit the use of identified QTL for comparative studies.The meta-QTL(MQTL)analysis is the meta-analysis of multiple QTL experiments,which entails broader allelic coverage and helps in the combined analysis of diverse QTL mapping studies revealing common genomic regions for target traits.In the present study,128(33.59%)out of 381 reported QTL(from 82 studies)for FDR could be projected on the maize genome through MQTL analysis.It revealed 38 MQTL for FDR(12 diseases)on all chromosomes except chromosome 10.Five MQTL namely 1_4,2_4,3_2,3_4,and 5_4 were linked with multiple FDR.Total of 1910 candidate genes were identified for all the MQTL regions,with protein kinase gene families,TFs,pathogenesis-related,and disease-responsive proteins directly or indirectly associated with FDR.The comparison of physical positions of marker-traits association(MTAs)from genome-wide association studies with genes underlying MQTL interval verified the presence of QTL/candidate genes for particular diseases.The linked markers to MQTL and putative candidate genes underlying identified MQTL can be further validated in the germplasm through marker screening and expression studies.The study also attempted to unravel the underlying mechanism for FDR resistance by analyzing the constitutive gene network,which will be a useful resource to understand the molecular mechanism of defense-response of a particular disease and multiple FDR in maize.

Identification and expression analysis of sugar transporter family genes reveal the role of ZmSTP2 and ZmSTP20 in maize disease resistance

Sugar is an indispensable source of energy for plant growth and development, and it requires the participation of sugar transporter proteins(STPs) for crossing the hydrophobic barrier in plants. Here, we systematically identified the genes encoding sugar transporters in the genome of maize(Zea mays L.), analyzed their expression patterns under different conditions, and determined their functions in disease resistance. The results showed that the mazie sugar transporter family contained 24 members, all of which were predicted to be distributed on the cell membrane and had a highly conserved transmembrane transport domain. The tissue-specific expression of the maize sugar transporter genes was analyzed, and the expression level of these genes was found to be significantly different in different tissues. The analysis of biotic and abiotic stress data showed that the expression levels of the sugar transporter genes changed significantly under different stress factors. The expression levels of Zm STP2 and Zm STP20 continued to increase following Fusarium graminearum infection. By performing disease resistance analysis of zmstp2 and zmstp20 mutants, we found that after inoculation with Cochliobolus carbonum, Setosphaeria turcica, Cochliobolus heterostrophus, and F. graminearum, the lesion area of the mutants was significantly higher than that of the wild-type B73 plant. In this study, the genes encoding sugar transporters in maize were systematically identified and analyzed at the whole genome level. The expression patterns of the sugar transporter-encoding genes in different tissues of maize and under biotic and abiotic stresses were revealed, which laid an important theoretical foundation for further elucidation of their functions.

Recent Progress in Elucidating the Structure, Function and Evolution of Disease Resistance Genes in Plants

Plants employ multifaceted mechanisms to fight with numerous pathogens in nature. Resistance （R） genes are the most effective weapons against pathogen invasion since they can specifically recognize the corresponding pathogen effectors or associated protein（s） to activate plant immune responses at the site of infection. Up to date, over 70 R genes have been isolated from various plant species. Most R proteins contain conserved motifs such as nucleotide-binding site （NBS）, leucine-rich repeat （LRR）, Toll-interleukin-1 receptor domain （TIR, homologous to cytoplasmic domains of the Drosophila Toll protein and the manamalian intefleukin-1 receptor）, coiled-coil （CC） or leucine zipper （LZ） structure and protein kinase domain （PK）. Recent results indicate that these domains play significant roles in R protein interactions with effector proteins from pathogens and in activating signal transduction pathways involved in innate immunity. This review highlights an overview of the recent progress in elucidating the structure, function and evolution of the isolated R genes in different plant-pathogen interaction systems.

Identification and Evaluation of Insect and Disease Resistance in Transgenic Cry1Ab13-1 and NPR1 Maize

PCR detection,quantitative real-time PCR(q-RTPCR),outdoor insect resistance,and disease resistance identification were carried out for the detection of genetic stability and disease resistance through generations(T2,T3,and T4)in transgenic maize germplasms(S3002 and 349)containing the bivalent genes(insect resistance gene Cry1Ab13-1 and disease resistance gene NPR1)and their corresponding wild type.Results indicated that the target genes Cry1Ab13-1 and NPR1 were successfully transferred into both germplasms through tested generations;q-PCR confirmed the expression of Cry1Ab13-1 and NPR1 genes in roots,stems,and leaves of tested maize plants.In addition,S3002 and 349 bivalent gene-transformed lines exhibited resistance to large leaf spots and corn borer in the field evaluation compared to the wild type.Our study confirmed that Cry1Ab13-1 and NPR1 bivalent genes enhanced the resistance against maize borer and large leaf spot disease and can stably inherit.These findings could be exploited for improving other cultivated maize varieties.

An Integrated QTL Map of Fungal Disease Resistance in Soybean (Glycine max L. Merr):A Method of Meta-Analysis for Mining R Genes

Diseases caused by fungal pathogens account for approximately 50% of all soybean disease losses around the world. Conflicting results of fungal disease resistance QTLs from different populations often occurred. The objectives of this study were to： （i） evaluate evidence for reported fungal disease resistance QTLs associations in soybean and （ii） extract relatively reliable and useful information from the ＂real＂ QTLs and mine putative genes in soybean. An integrated map of fungal disease resistance QTLs in soybean was established with soymap 2 published in 2004 as a reference map. QTLs of fungal disease resistance developed from each of separate populations in recent 10 years were integrated into a combinative map for gene cloning and marker assisted selection in soybean. 107 QTLs from different maps were integrated and projected to the reference map with the software BioMercator 2.1. A method of meta-analysis was used to narrow down the confidence interval, and 23 ＂real＂ QTLs and their corresponding markers were obtained from 12 linkage groups （LG）, respectively. Two published R genes were found in these ＂real＂ QTLs intervals. Sequences in the ＂real＂ QTLs intervals were predicted by GENSCAN, and these predicted genes were annotated in Goblet. 228 resistance gene analogs （RGAs） in 12 different terms were mined. The results will lay the foundation for a bioinformatics platform combining abundant QTLs, and offer the basis for marker assisted selection and gene cloning in soybean.

Transgenic Cotton and Disease Resistance Genes

Success in conventional breeding for resistance to mycotoxin-producing or other phytopathogenic fungi is dependent on the availability of resistance gene(s) in the germplasm.Even when it is available,breeding for disease-resistant crops is very time consuming,especially in perennial crops such

Cloning and Analysis of a Disease Resistance Gene Homolog from Soybean

Conserved domains e.g. nucleotide binding site (NBS) were found in several cloned plant disease resistance genes. Based on the NBS domain, resistance gene analogs (RGAs) have been isolated previously and were used as probes to screen a soybean (Glycine max L. Merr.) cDNA library. A full-length cDNA, KR3, was obtained by screening the library and rapid amplification of cDNA ends (RACE) method. Sequence analysis revealed that the cDNA is 2 353 bp in length and the open reading frame (ORF) codes for a polypeptide of 636 amino acids with a Toll-Interleukin-1 receptor (TIR) and a NBS domain. Sequence alignment showed that it was similar to N gene of tobacco. The phylogenetic tree analysis of R proteins with NBS from higher plants was performed. The KR3 gene has low copies in soybean genome and its expression was induced by exogenous salicylic acid (SA).

Transferring Translucent Endosperm Mutant Gene Wx-mq and Rice Stripe Disease Resistance Gene Stv-bi by Marker-Assisted Selection in Rice (Oryza sativa)

A high-yielding japonica rice variety, Wuyunjing 7, bred in Jiangsu Province, China as a female parent was crossed with a Japanese rice variety Kantou 194, which carries a rice stripe disease resistance gene Stv-b＇ and a translucent endosperm mutant gene Wx-mq. From F2 generations, a sequence characterized amplified region （SCAR） marker tightly linked with Stv-b＇ and a cleaved amplified polymorphic sequence （CAPS） marker for Wx-mq were used for marker-assisted selection. Finally, a new japonica rice line, Ning 9108, with excellent agronomic traits was obtained by multi-generational selection on stripe disease resistance and endosperm appearance. The utilization of the markers from genes related to rice quality and disease resistance was helpful not only for establishing a marker-assisted selection system of high-quality and disease resistance for rice but also for providing important intermediate materials and rapid selection method for good quality, disease resistance and high yield in rice breeding.

猕猴桃病程相关蛋白PR-1基因的克隆和功能分析

【目的】探究猕猴桃病程相关蛋白(pathogenesis-related proteins,PRs)PR-1基因在响应丁香假单胞杆菌中的功能。【方法】以毛花猕猴桃(Actinidia eriantha)为材料,克隆得到PR-1同源基因AePR-1全长序列,并对其序列进行生物信息学分析。采用实时荧光定量方法检测AePR-1基因在不同组织、花器官以及接种细菌性溃疡病菌(Psa)和不同激素(SA、ABA、GA_(3))处理条件下的表达情况。利用亚细胞定位技术分析AePR-1基因在细胞中的表达位置。通过在本氏烟草中过表达AePR-1基因,验证其在溃疡病菌响应过程中的功能。【结果】猕猴桃AePR-1基因序列全长522 bp,编码173个氨基酸,序列中含有6个保守的半胱氨酸结构基序和4个allergen V5/Tpx-1 related保守结构域。亚细胞定位发现AePR-1定位在细胞膜和细胞质中。AePR-1在猕猴桃根和雌蕊中高表达,且能够响应溃疡病菌及激素处理。过表达AePR-1的烟草在接种溃疡病菌后,叶片病斑数明显少于对照组。【结论】AePR-1基因在溃疡病菌和激素诱导下显著表达且过表达能够增强烟草对溃疡病的抗性,说明猕猴桃PR-1基因在响应生物和非生物胁迫中具有重要作用。

Breeding of Selectable Marker-Free Transgenic Rice Lines Containing AP1 Gene with Enhanced Disease Resistance

In order to obtain marker-free transgenic rice with improved disease resistance, the AP1 gene of Capsicum annuum and hygromycin-resistance gene （HPT） were cloned into the two separate T-DNA regions of the binary vector pSB130, respectively, and introduced into the calli derived from the immature seeds of two elite japonica rice varieties, Guangling Xiangjing and Wuxiangjing 9, mediated by Agrobacterium-mediated transformation. Many cotransgenic rice lines containing both the AP1 gene and the marker gene were regenerated and the integration of both transgenes in the transgenic rice plants was confirmed by either PCR or Southern blotting technique. Several selectable marker-free transgenic rice plants were subsequently obtained from the progeny of the cotransformants, and confirmed by both PCR and Southern blotting analysis. These transgenic rice lines were tested in the field and their resistance to disease was carefully investigated, the results showed that after inoculation the resistance to either bacterial blight or sheath blight of the selected transgenic lines was improved when compared with those of wild type.

Improving Rice Blast Resistance by Mining Broad-Spectrum Resistance Genes at Pik Locus

Magnaporthe oryzae is known for its genetic diversity and pathogenic variability,leading to rapid breakdown of resistance in rice.Incorporating multiple broad-spectrum blast resistance genes into rice cultivars would extend disease resistance longevity.Effective resistance breeding in rice therefore requires continual enrichment of the reservoir of resistance genes and alleles.We conducted a large-scale screen of rice blast resistance in about 2000 rice accessions.Among them,247 accessions showed at least medium resistance to the natural infection of rice blast and 7 novel Pik alleles were identified from them.Variations in gene sequences were then correlated with the phenotypic trait to enable the identification of favorable alleles.Among the seven novel Pik alleles,the resistant rate of Pik-R0/ME/7017 donors was greater than 80%,and the disease score was less than 3.Through molecular marker-assisted backcross breeding,we successfully transferred the three Pik alleles,Pik-R0/ME/7017,into an elite cultivated line Kongyu 131 to obtain BC_(3)F_(2)lines,which showed enhanced resistance to rice blast compared with the recurrent parent.Assessment of these near-isogenic lines in the greenhouse using 31 isolates of M.oryzae from Heilongjiang Province of China revealed that the resistant levels of the BC_(3)F_(2)lines with Pik-R0/ME/7017 were significantly higher than those of the established cloned resistance genes Pik-m and Pi1.Exploring such alleles will enrich our gene library for resistance to rice blast.

Bioinformatics Analysis of Disease Resistance Gene PR1 and Its Genetic Transformation in Soybeans and Cultivation of Multi-resistant Materials

In agricultural production,a single insect-resistant and disease-resistant variety can no longer meet the demand.In this study,the expression vector pCAMBIA-3301-PR1 containing the disease-resistant gene PR1 was constructed by means of genetic engineering,and the PR1 gene was genetically transformed to contain the PR1 gene through the pollen tube method.In CryAb-8Like transgenic high-generation T7 receptor soybean,a new material that is resistant to insects and diseases is obtained.For T2 transformed plants,routine PCR detection,Southern Blot hybridization,fluorescence quantitative PCR detection,indoor and outdoor pest resistance identification and indoor disease resistance identification were performed.The results showed that there were 9 positive plants in the routine PCR test of T2 generation.In Southern Blot hybridization,both PR1 and CryAb-8Like genes are integrated in soybeans in the form of single copies.Fluorescence quantitative PCR showed that the expression levels of PR1 and CryAb-8Like genes are different in different tissues.The average expression levels of PR1 gene in plant roots,stems,and leaves are 2.88,1.54,and 5.26,respectively.CryAb-8Like genes are found in roots,stems,and leaves.The average expression levels were 1.36,1.39,and 4.25,respectively.The insectivorous rate of the CryAb-8Like gene in outdoor plants with positive insect resistance identification was 3.78%.The disc partition method was used indoors for pest resistance identification,and the bud length of transformed plants increased significantly.The average mortality rate of untransformed plants in indoor disease resistance identification was as high as 56.66%,and the average mortality rate of plants transformed with PR1 gene was 10.00%,and disease resistance was significantly improved.Therefore,a new material with resistance to diseases and insects is obtained.

过表达杜仲EuDIR1基因对番茄灰霉病的抗性影响研究

Dirigent(DIR)蛋白在木质素的合成中发挥重要作用,同时还能提高植物对各种病原体的抗性。本研究以克隆的杜仲Dirigent1基因(EuDIR1)为基础,构建EuDIR1过表达载体遗传转化番茄,获得转基因植株后分析EuDIR1基因在番茄抗灰霉病中的作用。结果表明,与野生型和转空载番茄相比,接种灰霉菌后过表达EuDIR1基因的番茄发病更晚,病斑直径显著小于野生型与转空载植株,说明EuDIR1显著提高了番茄植株对灰霉病的抗性。过表达EuDIR1基因还可提高番茄植株接菌前后的保护酶活性与番茄病程相关蛋白(PRs)的基因表达,从而增强植株对灰霉病的抗性。此外,EuDIR1基因过表达后番茄叶片和茎的木质素含量都显著增加,且木质部导管附近的细胞壁显著增厚,推测EuDIR1基因可能通过增加番茄中木质素的含量,增厚番茄木质部导管附近的细胞壁来增强番茄对灰霉病的抗性。本研究揭示EuDIR1基因在番茄抗灰霉病中的功能,可为番茄抗病育种提供理论依据和利用途径。

东北春小麦抗秆锈病基因Sr31的分子检测及其抗性分析

为促进东北春小麦抗性育种,利用与抗秆锈病基因Sr31连锁的分子标记SCSS30.2和iag95,对300份东北春小麦抗秆锈病基因进行分子检测及抗性分析。结果表明,在300份春小麦品种中,有8份小麦品种被检测到含有iag95或SCSS30.2分子标记,含有抗秆锈病Sr31基因,而小麦品种农林45号中只鉴定到了含有iag95标记,钢09-558中只鉴定到了含有SCSS30.2标记。通过ω-sec标记,发现9.67%的供试材料含有1BL/1RS易位系。其中,同时携带与抗性基因Sr31连锁的两个标记SCSS30.2和iag95的8份材料,均被检测到含有1BL/1RS易位系。田间抗性鉴定进一步表明,被SCSS30.2检测到的9个材料中,除黑春1号外,其余材料在田间均表现出了极强的抗病性。而仅被iag95标记检测到的农林45号,对21C3CTHQM和34MKGQM两类生理小种均表现为感病。本研究成功鉴定出携带Sr31基因及1BL/1RS易位系的小麦材料,可作为小麦抗病育种材料进一步利用。

Molecular Detection and Disease Resistance Identification of Transgenic Wheat with pti5-vp16 Gene

The immature embryos of wheat cultivars Liaochun10, Tiechun1 and Fengqiang3 were bombarded with gold particles coated with pti5 vp16 by gene gun and disease resistant regenerated plants were attained. In order to confirm that the plants are genuine transformed ones, a series of molecular tests were conducted as follows. Firstly, transient GUS expression test on embryos two days after bombardment was done. There were many obvious blue spots produced on the surface of bombarded embryos after GUS staining, in which the maximum reached to 85 blue spots per embryo. Secondly, PCR test was performed with DNA from the regenerated plants obtained after double selection with ppt. 6 plants were found PCR test positive. At last, further verification analysis using dot hybridization and southern blotting was carried out on those PCR positive plants and the strong hybridization signals appeared as expected. All the above tests were uniformly indicated that the disease resistant regenerated plants were true transgenic plants. When inoculated with Blumeria graminis, transgenic wheat plants of PCR positive results were mostly resistant(R) after 7 days, and resis tant, moderate resistant(MR), moderate susceptible(MS) at 14 days respectively. The disease severity of them was distinctively lighter than that of control.

(R)-(+)-长叶薄荷酮对耐药结核分枝杆菌抑制作用及其生物被膜调控基因的影响

目的 研究(R)-(+)-长叶薄荷酮对耐药结核分枝杆菌体外抑制作用及其生物被膜调控基因Rv0024、Rv2872、Ra1362的影响。方法 通过聚合酶链反应(Polymerase chain reaction, PCR)筛选含生物被膜调控基因Rv0024、Rv2872、Ra1362的耐药结核分枝杆菌,采用刃天青显色法和液体培养计数法测定(R)-(+)-长叶薄荷酮对生物被膜介导的耐药结核分枝杆菌的最小抑菌浓度(Minimal inhibit concentration, MIC)和最低杀菌浓度(Minimum bactericidal concentration, MBC),应用反转录-聚合酶链式反应(Reverse transcription-polymerase chain reaction, RT-PCR)检测(R)-(+)-长叶薄荷酮对耐药结核分枝杆菌生物被膜调控基因Rv0024、Rv2872、Ra1362的影响。结果 在3×10^(7) CFU/mL和3×10^(6) CFU/mL菌液浓度下,刃天青显色法测得(R)-(+)-长叶薄荷酮对耐药结核分枝杆菌的MIC和MBC分别为14.79、29.59 mg/mL;液体培养计数法测得(R)-(+)-长叶薄荷酮对耐药结核分枝杆菌的MIC_(90)和MBC分别为19.89、24.62 mg/mL。RT-PCR法结果表明长叶薄荷酮可抑制Rv0024、Ra1362的表达,促进Rv2872的表达(P<0.05)。结论 (R)-(+)-长叶薄荷酮通过调控耐药结核分枝杆菌生物被膜主要基因Rv0024、Rv2872、Ra1362的表达,达到抑制耐药结核分枝杆菌的生长的作用。

Pyramiding the disease resistant genes to southern rust and stalk rot in maize(Zea mays L.) with marker-assisted selection

Southern corn rust(SCR) caused by Puccinia polysora Underw and maize stalk rot caused by Pythium inflatum Matthews(MSR-2) are two destructive diseases of maize(Zea mays L.) in China.Our previous studies indicated that maize inbred line Qi319 is highly resistant to SCR but susceptible to MSR-2,while inbred line 1145 is highly resistant to MSR-2 but susceptible to SCR.The SCR resistant gene(RppQ) in Qi319 and MSR-2 resistant gene(Rpi1) in 1145 have been mapped on chromosome 10 and 4 respectively.In this research,through marker-assisted selection(MAS) with the molecular markers,bnlg1937 tightly linked to Rpi1 and phi041 tightly linked to RppQ,pyramid breeding of the two kinds of disease resistant genes were carried out from the year of 2003 to 2007.Two homozygotic inbred lines of F5 generation,DR94-1-1-1 and DR36-1-1-1 were identified.MAS result suggested DR94-1-1-1 and DR36-1-1-1 contained the two resistance genes RppQ and Rpi1.Field inoculation tests confirmed their high resistance to the two diseases.In addition,field investigation indicated that the two selected inbred lines,particularly DR94-1-1-1,had excellent agronomic traits such as plant height,ear height and yield-relating traits including ear length,ear diameter,ear weight,kernels per ear,kernels per row and kernel weight per ear.The two selected inbred lines DR94-1-1-1 and DR36-1-1-1 can either be directly developed into commercial variety or used as immediate donors of SCR and MSR resistance breeding programs in maize.

Cloning and Sequence Analysis of Disease Resistance Gene Analogues from Three Wild Rice Species in Yunnan

Two sets of degenerate oligonucleotide primers were designed according to amino acid conserved regions of reported plant disease resistance genes which encode proteins that contain nucleotide-binding site and leucine-rich repeats(NBS-LRR), and the plant disease resistance genes which encode serine/threonine protein kinase(STK). By polymerase chain reaction(PCR), disease resistance gene analogues have been amplified from three wild rice species in Yunnan Province, China. The DIN A fragments from amplification have been cloned into the pGEM-T vector respectively. Sequencing of the DNA fragments indicated that 7 classes, 2 classes and 6 classes NBS-LRR disease resistance gene analogues from Oryza rufipogon Griff. , Oryza officinalis Wall. , and Oryza meyeriana Baill. were obtained respectively. The two representative fragments of TO12 from Oryza officinalis Wall, and TR19 from Oryza rufipogon Griff, belong to the same class and homology of their sequences are 100%. The result shows that the sequences of the same class disease resistance gene analogues have no difference among different species of wild rice. 5 classes STK disease resistance gene analogues were also obtained among which 4 classes from Oryza rufipogon Griff. , 1 class from Oryza officinalis Wall. By comparison analysis of amino acid sequences. we found that the obtained disease resistance gene analogues have very low identity(low to 25%) with the reported disease resistance gene L6, N, Bs2, Prf, Pto, Lr10 and Xa21 etc. The finding suggests that the obtained disease resistance gene analogues are analogues of putative disease resistance genes that have not been isolated so far.

基于CRISPR/Cas9技术的SIRT3基因敲除猪肺泡巨噬细胞系的构建与鉴定

【目的】旨在构建稳定敲除SIRT3基因的猪肺泡巨噬细胞系,分析SIRT3敲除对病毒诱导的炎症反应的调控作用,为探究SIRT3基因在宿主抗病毒感染中的作用奠定试验基础。【方法】研究利用CRISPR/Cas9基因编辑技术,针对猪SIRT3基因第2号外显子设计sgRNA,连接pb-U6-puro-BFP质粒后转染3D4/21细胞,筛选单克隆细胞,结合Sanger测序、qPCR和Western blot技术对获得的单克隆细胞进行鉴定,进而获得SIRT3基因敲除的猪肺泡巨噬细胞系(3D4/21-SIRT3-KO),并以流感病毒A/WSN/33为研究对象,感染野生型和3D4/21-SIRT3-KO猪肺泡巨噬细胞,利用qPCR方法检测炎症相关因子IL-6、IL-8的表达水平,初步分析SIRT3基因在流感病毒感染诱导炎症反应的影响。【结果】Sanger测序结果显示,在挑选获得的敲除SIRT3基因的猪肺泡巨噬细胞克隆中,SIRT3基因第2号外显子位点产生了碱基缺失,并导致移码突变;同时,利用qPCR和Western blot检测猪肺泡巨噬细胞中SIRT3 mRNA和蛋白水平的表达,结果显示与野生型细胞相比,3D4/21-SIRT3-KO细胞中SIRT3 mRNA和SIRT3蛋白均不表达;流感病毒感染SIRT3基因敲除的猪肺泡巨噬细胞时发现,敲除SIRT3能显著加剧流感病毒感染诱导的炎症反应。【结论】研究利用CRISPR/Cas9基因编辑技术成功构建了SIRT3基因敲除的猪肺泡巨噬细胞系,并初步分析了SIRT3在流感病毒感染中作用。

甘蔗抗褐锈病Bru1区域的鉴定及候选抗病基因的功能分析

【目的】甘蔗褐锈病是由黑顶柄锈菌(Puccinia melanocephala H. Sydow&P. Sydow)引起的最具破坏性的真菌病害之一,能造成蔗糖分降低10%—36%,严重威胁甘蔗产业发展。已有研究揭示抗褐锈病主效基因定位于Bru1区域,克隆其关键候选基因,并进行功能研究,为选育抗褐锈病甘蔗新品种提供重要的候选基因资源。【方法】利用PacBio SequelⅡ测序平台获得甘蔗栽培品种ROC22的contig水平基因组信息,鉴定到抗褐锈病Bru1区域,对其进行基因注释和克隆,分析其组织特异性和抗、感褐锈病甘蔗品种中的表达模式及其在烟草叶片的亚细胞定位和瞬时表达。【结果】基于Bru1位点区域紧密连锁的标记R12H16和9O20-F4,从该区域中注释到33个基因,结合典型抗病基因结构域,共筛选获得5个候选抗病基因,分别为Brrg99、Brrg103、Brrg108、Brrg115和Brrg116。以甘蔗栽培品种ROC22的cDNA为模板,克隆获得Brrg116的全长序列729 bp,编码242个氨基酸残基。将该基因序列分别比对甘蔗热带种和割手密种及二倍体近缘种高粱的基因组数据库,发现其与热带种和割手密种的同源基因序列相似性很高,达到98%以上,而与高粱的相似性为93.77%。系统进化树揭示该基因起源甘蔗割手密种。实时荧光定量PCR检测表明,Brrg116在甘蔗栽培品种的多个组织中组成型表达,尤其是在+1叶中的表达量最高,是蔗芽的9.8倍;在褐锈病菌侵染抗、感甘蔗栽培品种的6和72 h时,呈现显著差异表达。亚细胞定位结果显示,该基因编码蛋白定位于细胞膜上。在本氏烟(Nicotiana benthamiana)叶片中瞬时过表达Brrg116,其后接种茄病镰刀菌蓝色变种,二氨基联苯胺法(3,3′-diaminobenzidine,DAB)染色逐渐加深,超敏反应相关基因、水杨酸信号和乙烯信号途径中的相关基因持续上调表达。【结论】Brrg116在甘蔗不同组织中组成型表达,且在受褐锈病菌侵染的抗病甘蔗栽培品种中呈现快速的诱导表达。此外,过表达Brrg116引发水杨酸和乙烯等激素信号通路产生防御响应,推测该基因可能在提高植物的抗病性方面发挥重要调控作用。