Wheat powdery mildew caused by Blumeria graminis f. sp tritici (Bgt), an obligate biotrophic fungal pathogen, is a destructive disease world-wide, particularly severe in China. However, the molecular mechanisms underlying virulence variation and pathogenesis of Chinese Bgt isolates remain poorly understood. Here, we constructed a chromosome-level genome assembly (136.19 Mb) of Chinese isolate 21-2, with repetitive element expansion (predominantly retrotransposons), by integrating Illumina, PacBio, Nanopore, and Hi-C sequencing technologies. The genome was predicted to contain 9215 protein-coding genes, of which 1569 were assessed as pathogenicity-related genes. This included 998 effectors, 371 involved in pathogen-host interactions (PHI), 223 CAZymes-encoding with plant cell wall degrading capacity, and 79 lipase-coding implicated in pathogenic infection. Compared to Swiss isolate 96224, isolate 21-2 displayed a distinct virulence pattern on 21 wheat differential lines. Comparative genomics analysis revealed that variations in composition and sequence of effector genes between the two isolates resulted in different virulence spectra (e.g., AvrPm1a, AvrPm3a 2/f2, AvrPm3b2/c2, AvrPm3d3 ). Transcriptome analysis of 21-2 revealed 64 effector genes exhibiting preferential expression during haustorial development, suggesting their potential involvement in pathogenesis. Among them, one can bind a defence-related protein of wheat and may play a key role in suppressing host immune responses and promoting disease progression. This study provides comprehensive genomic and transcriptomic insights into Chinese Bgt isolate 21-2, and reveals virulence determinants and their variants fundamental to pathogenesis. Future functional analysis of such genes will enhance our understanding of pathogenic mechanisms of powdery mildews.

Cereal powdery mildews, which are caused by Blumeria graminis, are economically important diseases that are distributed throughout the world. To successfully evade the host defence mechanism, the wheat powdery mildew pathogen known as B. graminis f. sp. tritici (Bgt) secretes an array of effectors into plant cells to interfere with host immunity and promote fungal invasion and colonisation during the infection process. However, little is known about the functions of the vast majority of these effectors in immune manipulation. In this study, we identified an effector-coding gene known as BgtE-20069a from Bgt. This gene encodes a short protein carrying an N-terminal signal peptide with a secretory function and is highly upregulated in the early stage of Bgt infection in wheat. We observed that transient expression of BgtE-20069a in Nicotiana benthamiana suppressed programmed cell death (PCD) induced by both the proapoptotic protein Bax and the elicitor PAMP INF1 from Phytophthora infestans. The mature form of BgtE-20069a (which lacks a signal peptide) is localised to the cytoplasm and nucleus of plant cells. Moreover, the knockdown of BgtE-20069a resulted in reduced virulence towards wheat, with significantly decreased conidia production and a decreased haustorial formation rate being observed. Together, these results suggest that BgtE-20069a is a vital virulence factor that is required for Bgt infection in wheat; moreover, the results indicate that it can suppress plant immunity and increase Bgt virulence. Our findings broaden the current understanding of the role of effectors in promoting Bgt infection by manipulating host immunity, thereby providing new insights into the molecular mechanism of Bgt pathogenesis.

Crop wild relatives offer natural variations of disease resistance for crop improvement. Here, we report the isolation of broad-spectrum powdery mildew resistance gene Pm36, originated from wild emmer wheat, that encodes a tandem kinase with a transmembrane domain (WTK7-TM) through the combination of map-based cloning, PacBio SMRT long-read genome sequencing, mutagenesis, and transformation. Mutagenesis assay reveals that the two kinase domains and the transmembrane domain of WTK7-TM are critical for the powdery mildew resistance function. Consistently, in vitro phosphorylation assay shows that two kinase domains are indispensable for the kinase activity of WTK7-TM. Haplotype analysis uncovers that Pm36 is an orphan gene only present in a few wild emmer wheat, indicating its single ancient origin and potential contribution to the current wheat gene pool. Overall, our findings not only provide a powdery mildew resistance gene with great potential in wheat breeding but also sheds light into the mechanism underlying broad-spectrum resistance. Powdery mildew is a fungal leaf disease that reduces yield and grain quality in susceptible wheat varieties. Here, the authors report the cloning of the wild emmer wheat originated powdery mildew resistance gene Pm36 as a membrane associated tandem kinase and its possible resistance mechanism.

Tomato is consumed worldwide as fresh or processed food products. However, soilborne diseases of tomato plants caused by coinfection of various pathogens result in great economic losses to the tomato industry. It is difficult to accurately identify and diagnose soilborne diseases of tomato plants caused by pathogen complexes. In this study, we investigated field diseases of tomato plants by pathogen isolation and molecular identification and found that tomato wilt was caused by coinfection of Fusarium brachygibbosum, F. oxysporum, and Ralstonia solanacearum. Therefore, developing a method for simultaneous detection of DNA from F. brachygibbosum, F. oxysporum, and R. solanacearum is of great importance to efficiently and accurately monitor disease development at different growth stages of tomato plants. In this study, we performed a comparative genomic analysis of F. brachygibbosum, F. oxysporum, and R. solanacearum and determined the primer sets for simultaneous detection of DNA from these target pathogens. Then, we tested the reagent and condition parameters of multiplex PCR, including primers, dNTP and Mg2+ concentrations, and annealing temperatures, to determine the optimal parameters of a multiplex PCR system. We evaluated the specificity, sensitivity, and stability of the multiplex PCR system based on the optimized reaction conditions. The multiplex PCR system can specifically identify 13 target pathogens from 57 different fungal and bacterial pathogens, at the lower detection limit of the three target pathogens at concentrations of 100 pg/μl. In addition, we can accurately identify the three pathogens in tomato plants using the optimized multiplex PCR method. These results demonstrated that the multiplex PCR method developed in this study can simultaneously detect DNA from F. brachygibbosum, F. oxysporum, and R. solanacearum in a single PCR system to accurately identify and diagnose the pathogen causing tomato wilt.

Diseases caused by two or more soil-borne pathogens are called compound soil-borne diseases. We have pioneered the "root splitter" and the imaging analysis system, providing a new tool for studying compound soil-borne diseases and a new method for evaluating crop resistance and pesticide (fertilizer) efficacy, and laying a foundation for the development of microbial agents, pesticides, and fertilizers. On this basis, we have developed a range of soil-borne disease disturbance agents “G15”, including a series of bio-organic fertilizers, liquid fertilizers and immune inducers. a) Microecological control series of bio-organic fertilizer: a new method of strain culture and classification screening based on the information of main components of organic fertilizer materials was used to obtain strains with high matching degree with organic materials. Then the process optimization technology was renewed by the ferulic acid rapid detection system. Through the 2-hour rapid detection and 30-day rapid optimization, the qualification rate of products is over 95%. It also standardized the basic operation methods and application doses for different crops and different application methods, and stabilized the application effect of products. The application of bioorganic fertilizers significantly reduced the abundance of pathogenic fungi and bacteria in the soil, and significantly inhibited the development of Solanaceae and Cucurbits wilt in the field (Figure 1A & 1B). b) Liquid fertilizer series products: liquid fertilizer with large, medium and trace elements, including nanometer silicon, ionic boron, ionic calcium, macroelement water-soluble fertilizer etc, which can improve crop quality and yield, increase disease resistance. We found that nano-silicon, ionic boron and ionic calcium can significantly promote the growth and disease resistance of grape (Figure 2). c) Salicylic Acid (SA), an immune inducer product, can improve the microbiological structure of soil by flushing with basic fertilizer; Foliar spraying can promote the expression of crop resistance genes, enhance the ability of drought resistance, salt resistance, oxidation resistance and heavy metal resistance, and improve the stress resistance and disease resistance of crops; Soaking or spraying can store the harvested fruits and keep them fresh; Combined with liquid fertilizer series products, crops can be put on the market early. However, SA is a natural product widely used in the plant kingdom and has a wide range of regulatory effects on plant resistance and growth. SA is slightly soluble in water and easily soluble in ethanol, ether and chloroform, so the concentration of SA solution is currently limited and the highest concentration can reach only 8%. Therefore, the concentration of SA and a higher proportion of ethanol in the solution limit the wide use of SA solution. In this study, we added willow bark to an aqueous solution containing PH 2.0-3.5 and soaked it at room temperature under the action of ultrasound and electrostatic field, which promoted the dissolution of water-soluble components and inhibited the dissolution of SA. After filtering the aqueous solution, polyethylene glycol was added to increase the solubility of SA, and finally the SA solution with a concentration of more than 12% was obtained. In order to verify the effect of the high content of SA on improving crop yield and ripening. We applied the leaf spray method to immature tomatoes in the field. The results showed that the total weight of 30 tomatoes in the treatment group was 7.4 kg, while in the control group it was 5.55 kg, an increase of 32.97%. The tomatoes in the treatment group were red in a wide range and reached the level of natural ripeness, while the tomatoes in the control group were cyan in a wide range and were not yet ripe. In addition, the average sugar content of tomatoes in the treatment group was 7.33, while it was 5.85 in the control group (Figure 3). The results suggest that spraying with a highly concentrated SA solution before flowering and harvesting can increase the yield and sweetness of tomatoes, adjust the uniform ripening time of tomatoes, effectively reduce tomato cultivation obstacles and harvesting costs, and improve the benefits of cultivation. Therefore, in order to prevent and control the compound soil-borne diseases caused by multiple soil-borne pathogens, we proposed a combination of bio-organic fertilizers, liquid fertilizers with large, medium and trace elements and immune inducers to regulate the composition of soil microbial community, improve the soil ecological environment and promote crop growth to comprehensively control the compound soil-borne diseases.

Black spot disease (PBS) caused by Alternaria alternata is an economic disease of pear ( Pyrus pyrifolia Nakai). Developing cultivars with durable PBS resistance traits is an important research objective for improving pear germplasm. The Deshengxiang is a popular pear variety in China and resistant to PBS. This study aimed to detect quantitative trait loci (QTL) associated with PBS resistance trait in pear and determine closely linked molecular markers by specific locus amplified fragment sequencing (SLAF-seq). F1 population resulting from a cross between “Deshengxiang” (female) and “Guiguan,” a susceptible (male) variety, was developed and evaluated in 2016 and 2017. SLAF technology was used to discover SNPs in the F1 individuals and subsequently a high-density genetic linkage map for PBS resistance was constructed which contained 17,604 SNP markers. Based on the linkage map, the markers were distributed into 17 linkage groups, spanning 1548.48 cM, with a mean marker distance of 0.09 cM, representing the densest genetic map of the genus Pyrus . QTL analysis of PBS resistance identified a locus strongly related to PBS resistance at 77.68 ~ 112.99 cM on linkage group 15, which was further narrowed down to 93.79 ~ 112.99 cM. Two markers, Marker94293 and Marker94206, located at 97.47 and 102.93 cM, were closely associated with PBS resistance, with a Δ (SNP index) value of 0.46. Co-localization of QTL interval, bioinformatics analysis, and functional annotation revealed PBS putative candidate genes. Overall, the high-density pear linkage map is a suitable reference for mapping PBS resistance trait, QTL, and genes identified in this study contribute information that could be useful for PBS improvement in pear.

为了明晰小麦白粉菌BgtVosA、BgtVelB、BgtBrlA基因的序列特点及它们在白粉菌产孢过程中的表达动态,为解析velvet蛋白在调控白粉菌无性繁殖中的作用提供理论依据,采用基于 RNA-seq数据的克隆测序技术获得BgtVosA、BgtVelB、BgtBrlA基因的CDS序列,用生物信息学方法分析它们编码的蛋白质序列特征和空间结构,用RT-qPCR监测它们在白粉菌分生孢子形成时期的表达模式.结果表明,BgtVosA、BgtVelB、BgtBrlA基因的ORF长度依次为1470、1341、1143bp,分别编码489、446、380个氨基酸,分子量在54.0～48.0ku,属于碱性、亲水性、热不稳定蛋白质,均含有核定位信号,不含跨膜螺旋和信号肽,空间结构呈现出近球形.BgtVosA、BgtVelB、BgtBrlA分别与其他真菌来源的VosA、VelB、BrlA蛋白具有同源性,且与白粉菌同源蛋白具有更近的亲缘关系,氨基酸序列在白粉菌自然群体中均高度保守.BgtVosA、BgtVelB属于典型的velvet蛋白家族成员,可能通过分子互作形成复合物,但其结构与构巢曲霉同源蛋白复合物存在明显差异.在小麦白粉菌无性繁殖阶段,BgtVosA、BgtVelB基因均显著上调(P＜0.01),BgtBrlA表达水平没有显著变化(P＞0.05).DNA结合区域分析推测BgtVosA-BgtVelB复合物不能靶向BgtBrlA启动子,调控其BgtBrlA的表达.BgtVosA、BgtVelB基因在调控白粉菌无性生殖中起重要作用.

The discovery of natural bioactive compounds from endophytes or medicinal plants against plant diseases is an attractive option for reducing the use of chemical fungicides. In this study, three compounds, indole-3-carbaldehyde, indole-3-carboxylic acid (3-ICA), and jasmonic acid (JA), were isolated from the EtOAc extract of the culture filtrate of the endophytic fungus Lasiodiplodia pseudotheobromae LPS-1, which was previously isolated from the medicinal plant, Ilex cornuta. Some experiments were conducted to further determine the antifungal activity of these compounds on wheat powdery mildew. The results showed that JA was much more bioactive than indole-3-carbaldehyde and 3-ICA against Blumeria graminis, and the disease severity caused by B. graminis decreased significantly with the concentration increase of JA treatment. The assay of the interaction of 3-ICA and JA indicated that there was a significant synergistic effect between the two compounds on B. graminis in each of the ratios of 3-ICA to JA (3-ICA:JA) ranging from 1:9 to 9:1. When the compound ratio of 3-ICA to JA was 2:8, the synergistic coefficient was the highest as 22.95. Meanwhile, a histological investigation indicated that, under the treatment of JA at 500 μg/ml or 3-ICA:JA (2:8) at 40 μg/ml, the appressorium development and haustorium formation of B. graminis were significantly inhibited. Taken together, we concluded that JA plays an important role in the infection process of B. graminis and that 3-ICA as a synergist of JA enhances the antagonism against wheat powdery mildew.

为明确品种抗性、杀菌剂施药时期和防治次数相结合对小麦赤霉病(Fusarium head blight,FHB)病情指数(Disease index,DI)、脱氧雪腐镰刀菌烯醇(Deoxynivalenol,DON)毒素含量和千粒重(Thousand-grain weight,TGW)的影响,2016-2018年连续2个年度使用6个不同抗性水平的冬小麦品种('郑麦9023,'鄂麦006''鄂麦170''襄麦35''鄂麦DH16''宁麦13'),分别在扬花初期和扬花初期第6天喷施430 g/L戊唑醇防治小麦赤霉病,对病情指数、脱氧雪腐镰刀菌烯醇毒素含量和千粒重进行评价.结果表明:品种抗性和杀菌剂对DI、DON毒素含量和TGW的影响极显著(P＜0.000 1);品种×杀菌剂联合作用,对TGW影响不显著(P＞0.05);杀菌剂防治1次和2次对中抗品种的DI和DON毒素含量差异不显著;比较品种间DI和DON的防效,中抗品种对DI和DON毒素积累的防治效果要显著高于中感病品种(P＜0.05).因此,品种抗性与药剂相结合是防治小麦赤霉病和DON毒素积累的有效策略.

猕猴桃溃疡病是由丁香假单胞菌猕猴桃致病变种(Pseudomonas syringae pv.actinidiae,Psa)引起的细菌性病害,严重影响猕猴桃产业发展.明确猕猴桃溃疡病在田间的传播对其防治具有重要意义.本研究于2020年4月16—22日和2021年3月24—30日,在湖北省赤壁市调查了半岛南猕猴桃种植园区内猕猴桃溃疡病的发病情况,通过孢子捕捉器在猕猴桃园区的不同地势(坡度为10°、30°和45°的区域)和不同天气环境下进行24 h连续病原捕集,并据猕猴桃叶片上溃疡病显症所需时长反映不同地势和天气环境对病害传播的影响.结果表明,在坡度10°区域进行病原捕集的猕猴桃叶片显症所需时间比坡度30°和45°区域晚1～2 d.雨天在孢子捕捉器内的叶片上显症所需时长仅需7 d,而晴天显症时长则需10～12 d.明确了露地栽培猕猴桃园区坡度和雨天显著促进了猕猴桃溃疡病的传播.对猕猴桃溃疡病防治技术制订和实施有一定意义.

Cultivated wheat is continually exposed to various pathogens. Blumeria graminis f. sp. tritici (Bgt) causes powdery mildew disease and significant yield loss. Pm60 was cloned from Triticum urartu and confers race-specific powdery mildew resistance in wheat. Pm60a and Pm60b are allelic variants of Pm60 and have two leucine-rich repeat motifs deletions and insertions, respectively, which were detected in other T. urartu accessions. Through map-based cloning, virus-induced gene silencing, and stable transformation assays, we demonstrated that Pm60a and Pm60b conferred Bgt E09 resistance resembling that provided by Pm60. However, the homozygous Pm60a (but not Pm60 or Pm60b) transformants driven by the native promoters lacked race-specific resistance when they were inoculated with Bgt E18. As all three T. urartu accessions contained the three foregoing alleles, they had high resistance to Bgt E18. Pyramiding Pm60a with either of the allelic genes in F1 plants did not cause mutual allele suppression or interference with Bgt E18 resistance. Deletion (but not insertion) of the two leucine-rich repeat motifs in Pm60a substantially narrowed the resistance spectrum. In T. urartu accession PI428210, we identified another locus adjacent to Pm60a and resistant to Bgt E18. Characterization of the alleles at the Pm60 locus revealed their diversity and similarity and may facilitate wheat breeding for resistance to powdery mildew disease caused by B. graminis f. sp. tritici.

为明确不同轮作模式对小麦赤霉病菌种群结构和毒素化学型影响,于2019-2020两个小麦生长季,从湖北襄阳、枣阳长期稻-麦轮作和长期玉-麦轮作田分别采集小麦赤霉病穗,采用组织病理学分离镰孢菌单孢堆菌株,并对其采用特异性引物进行致病种和毒素化学型分子鉴定.结果表明,从采集样品中共分离获得191个镰孢菌单抱堆菌株;亚洲镰抱菌F.asiaticum为该区稻-麦轮作田优势种,占稻-麦轮作田分离菌株总数的93.0％,主要产生3-AcDON;禾谷镰抱菌F.graminearum为玉-麦轮作田优势种,占玉-麦轮作田分离菌株总数的62.9％,既可能产生15-AcDON,又可能产生3-AcDON;191个菌株中仅有11个菌株产生NIV,占比5.8％.以上结果揭示,小麦赤霉病镰孢菌致病种和毒素化学型组成与轮作模式密切相关,镰孢菌优势致病种和毒素的类型可能与镰孢菌对小麦前茬作物的偏好性有关.

旨在探明水稻秸秆生物炭施用量和施用时期对江汉平原稻茬麦养分吸收、土壤养分含量以及产量的影响.选择江汉平原典型潮土稻麦轮作区,以基施化肥但不施生物炭处理为对照,设置小麦播种前基施、返青拔节期追施以及两个时期同施不同剂量的生物炭等处理,采用比色法和火焰光度计法测定了不同处理小麦籽粒、植株茎叶和土壤的氮、磷、钾含量,并比较了籽粒产量的变化.结果 表明,施用生物炭促进了小麦籽粒和植株茎叶对氮、磷、钾元素的吸收,增加了地上部分氮、磷、钾养分吸收总积累量,且以基施及追施13500 kg/hm2生物炭处理最高,较对照处理籽粒总氮、磷、钾分别提高了20.3％、17.8％和12.4％,茎叶总氮、磷、钾分别提高了11.9％、34.5％和13.9％,氮、磷、钾总积累量显著增加18.2％、24.0％、13.7％(P＜0.05);施用生物炭后土壤pH升高、有机质和速效磷含量增加,小麦株高增高,结实率和千粒重增大.施用水稻秸秆生物炭对于改善土壤和提高小麦产量具有一定促进作用.

Pepper root rot is a serious soil-borne disease that hinders pepper production, and efforts are being made to identify biological agents that can prevent and control pepper root rot. Our group recently discovered and produced a biological agent, named G15, which reduces the diversity and richness of fungi and bacteria when applied to pepper fields. In the soil of the G15-treatment condition, the pathogenic fungus Fusarium was inhibited, while the richness of beneficial bacteria Rhodanobacter was increased. Also, the ammonia nitrogen level was decreased in the G15-treatment soil, and the pH, total carbon, and total potassium levels were increased. Compared to the control condition, pepper yield was increased in the treatment group (by 16,680 kg acre −1 ). We found that G15 could alter the microbial community structure of the pepper rhizosphere. These changes alter the physical and chemical properties of the soil and, ultimately, improve resistance to pepper root rot and increase pepper yield.

Wheat root rot disease due to soil-borne fungal pathogens leads to tremendous yield losses worth billions of dollars worldwide every year. It is very important to study the relationship between rhizosphere soil fungal diversity and wheat roots to understand the occurrence and development of wheat root rot disease. A significant difference in fungal diversity was observed in the rhizosphere soil of healthy and diseased wheat roots in the heading stage, but the trend was the opposite in the filling stage. The abundance of most genera with high richness decreased significantly from the heading to the filling stage in the diseased groups; the richness of approximately one-third of all genera remained unchanged, and only a few low-richness genera, such as Fusarium and Ceratobasidium , had a very significant increase from the heading to the filling stage. In the healthy groups, the abundance of most genera increased significantly from the heading to filling stage; the abundance of some genera did not change markedly, or the abundance of very few genera increased significantly. Physical and chemical soil indicators showed that low soil pH and density, increases in ammonium nitrogen, nitrate nitrogen and total nitrogen contributed to the occurrence of wheat root rot disease. Our results revealed that in the early stages of disease, highly diverse rhizosphere soil fungi and a complex community structure can easily cause wheat root rot disease. The existence of pathogenic fungi is a necessary condition for wheat root rot disease, but the richness of pathogenic fungi is not necessarily important. The increases in ammonium nitrogen, nitrate nitrogen and total nitrogen contributed to the occurrence of wheat root rot disease. Low soil pH and soil density are beneficial to the occurrence of wheat root rot disease.

为筛选防治小麦赤霉病的新型生物产品及其减药增效配方,于2016年分别在湖北襄阳和荆州开展田间试验.评价了植物免疫蛋白质生物农药6％寡糖·链蛋白可湿性粉剂、诱抗剂0.5％大黄素甲醚水剂和生物刺激素爱诺森可溶液剂对赤霉病的防治效果,筛选了上述3种生物产品与常规化学农药430 g/L戊唑醇悬浮剂、25％咪鲜胺乳油和50％多菌灵可湿性粉剂减药增效组合配方.结果表明:6％寡糖·链蛋白可湿性粉剂和0.5％大黄素甲醚水剂处理的防效分别在20.18％～24.37％和18.32％～22.98％之间,爱诺森处理对小麦赤霉病无防治效果.430 g/L戊唑醇悬浮剂、25％咪鲜胺乳油和50％多菌灵可湿性粉剂等3种杀菌剂减量20％分别与寡糖·链蛋白、大黄素甲醚和爱诺森复配田间防效表明,50％多菌灵可湿性粉剂减量20％与寡糖·链蛋白、大黄素甲醚和爱诺森3种生物产品复配处理的病情指数在3.34～7.81,防治效果在63.99％～77.56％,其增效范围在3.22％～47.59％,与430 g/L戊唑醇悬浮剂未减药用量的防效相当(P＞0.05).50％多菌灵可湿性粉剂减量20％与寡糖·链蛋白、大黄素甲醚和爱诺森3种生物产品复配处理的产量显著高于未减药的多菌灵处理产量(P＜0.05),增产幅度在3.74％～9.28％之间.430 g/L戊唑醇悬浮剂和25％咪鲜胺乳油减量20％与寡糖·链蛋白、大黄素甲醚和爱诺森3种生物产品复配处理的防效和增产效果趋势不显著.

Bacillus amyloliquefaciens strain EA19 is an endophyte isolated from Erigeron annuus with antifungal activity against Blumeria graminis f. sp. tritici , Magnaporthe oryzae , and Fusarium graminearum . The genome sequence of this strain is 3.96 Mb and contains 3,421 coding sequences, which will facilitate an understanding of the mechanisms of biocontrol.

采用田间试验研究了288 g/L氯氟吡氧乙酸异辛酯乳油防除小麦田主要阔叶杂草的效果,及杂草防除后对氮、磷、钾及水分的影响.结果表明,施用288 g/L氯氟吡氧乙酸异辛酯乳油防除小麦田杂草效果显著,对猪殃殃(Galium aparine L.)、牛繁缕[Malachium aquaticum(L.)Fries]和大巢菜(Vicia sativa L.)均有良好防效,60 d后综合鲜重防效达90.3％～99.9％.杂草防除后,显著降低了杂草对田间氮、磷、钾和水分的消耗,有效改善了田间的水肥条件.288 g/L氯氟吡氧乙酸异辛酯乳油处理的小麦田产量达3162.3～3401.7 kg/hm2,与清水对照相比增产效果显著,增产达23.0％～32.3％,每公顷增收1358.84～1909.46元.

Powdery mildew, a fungal disease caused byBlumeria graminisf. sp.tritici(Bgt), has a serious impact on wheat production. Loss of resistance in cultivars prompts a continuing search for new sources of resistance. Wild emmer wheat (Triticum turgidumssp.dicoccoides, WEW), the progenitor of both modern tetraploid and hexaploid wheats, harbors many powdery mildew resistance genes. We report here the positional cloning and functional characterization ofPm41, a powdery mildew resistance gene derived from WEW, which encodes a coiled-coil, nucleotide-binding site and leucine-rich repeat protein (CNL). Mutagenesis and stable genetic transformation confirmed the function ofPm41againstBgtinfection in wheat. We demonstrated thatPm41was present at a very low frequency (1.81%) only in southern WEW populations. It was absent in other WEW populations, domesticated emmer, durum, and common wheat, suggesting that the ancestralPm41was restricted to its place of origin and was not incorporated into domesticated wheat. Our findings emphasize the importance of conservation and exploitation of the primary WEW gene pool, as a valuable resource for discovery of resistance genes for improvement of modern wheat cultivars.

Powdery mildew, caused by Blumeria graminis f. sp. tritici ( Bgt ), is one of the most destructive diseases that pose a great threat to wheat production. Wheat landraces represent a rich source of powdery mildew resistance. Here, we report the map-based cloning of powdery mildew resistance gene Pm24 from Chinese wheat landrace Hulutou. It encodes a tandem kinase protein (TKP) with putative kinase-pseudokinase domains, designated WHEAT TANDEM KINASE 3 (WTK3). The resistance function of Pm24 was validated by transgenic assay, independent mutants, and allelic association analyses. Haplotype analysis revealed that a rare 6-bp natural deletion of lysine-glycine codons, endemic to wheat landraces of Shaanxi Province, China, in the kinase I domain (Kin I) of WTK3 is critical for the resistance function. Transgenic assay of WTK3 chimeric variants revealed that only the specific two amino acid deletion, rather than any of the single or more amino acid deletions, in the Kin I of WTK3 is responsible for gaining the resistance function of WTK3 against the Bgt fungus.