Tomato leaf curl Bangladesh病毒完整基因组上微卫星分布

为了展示Tomato leaf curl Bangladesh病毒完整基因组上的微卫星分布特性。借助MATLAB软件、应用最优完全子图算法,提取并展示NCBI数据库中Tomato leaf curl Bangladesh病毒完整基因组(AF_188481.1)上的微卫星分布特性,计算1-碱基组至6-碱基组在完整基因组序列上重复出现的次数和位置,展示它们的分布规律(指数函数)。结果表明:Tomato leaf curl Bangladesh病毒完整基因组(AF_188481.1)上各种N-碱基组(N取1至6)最大的重复出现次数,随N按指数函数数减少;笔者提取和展示Tomato leaf curl Bangladesh病毒完整基因组序列微卫星分布特性(特别是微卫星各种N-碱基组重复出现的位置和次数)的方法,可以系统地运用到其他病毒完整基因组序列微卫星分布特性的提取和展示中,从而为有效利用微卫星分布特性研究完整基因组的结构和功能、遗传和变异规律提供完备、仔细的数据支撑。

Understanding the mechanisms of resistance to tomato leaf mold:A review

Tomato leaf mold is a common disease in tomato production and severely impacts the growth,fruit quality and yield of tomato plants.Research on tomato leaf mold has a long history and has focused mainly on the differentiation of pathogen races,the structure and function of pathogen Avr gene products,the cloning of Cf resistance genes and the analysis of disease resistance mechanisms.Interactions between Cf and Avr are in accordance with the"gene-for-gene"hypothesis and typical Cf/Avr interactions are part of effector-triggered immunity(ETI).However,an increasing number of studies have proven that pathogen-associated molecular pattern(PAMP)-triggered immunity(PTI)is involved in the disease resistance response system mediated by Cf genes.In addition,different Cf genes have both similar and different roles in the disease resistance response,indicating that the disease resistance mechanism of Cf genes is complex.In this paper,progress in tomato leaf mold research was reviewed,and the regulatory mechanism underlying the Cf-mediated disease resistance response was thoroughly explored.We hope this summary will lay a foundation for research on tomato leaf mold disease resistance mechanisms and is applicable to breeding for disease resistance.

A Lightweight Deep Learning-Based Model for Tomato Leaf Disease Classification

Tomato leaf diseases significantly impact crop production,necessitating early detection for sustainable farming.Deep Learning(DL)has recently shown excellent results in identifying and classifying tomato leaf diseases.However,current DL methods often require substantial computational resources,hindering their application on resource-constrained devices.We propose the Deep Tomato Detection Network(DTomatoDNet),a lightweight DL-based framework comprising 19 learnable layers for efficient tomato leaf disease classification to overcome this.The Convn kernels used in the proposed(DTomatoDNet)framework is 1×1,which reduces the number of parameters and helps in more detailed and descriptive feature extraction for classification.The proposed DTomatoDNet model is trained from scratch to determine the classification success rate.10,000 tomato leaf images(1000 images per class)from the publicly accessible dataset,covering one healthy category and nine disease categories,are utilized in training the proposed DTomatoDNet approach.More specifically,we classified tomato leaf images into Target Spot(TS),Early Blight(EB),Late Blight(LB),Bacterial Spot(BS),Leaf Mold(LM),Tomato Yellow Leaf Curl Virus(YLCV),Septoria Leaf Spot(SLS),Spider Mites(SM),Tomato Mosaic Virus(MV),and Tomato Healthy(H).The proposed DTomatoDNet approach obtains a classification accuracy of 99.34%,demonstrating excellent accuracy in differentiating between tomato diseases.The model could be used on mobile platforms because it is lightweight and designed with fewer layers.Tomato farmers can utilize the proposed DTomatoDNet methodology to detect disease more quickly and easily once it has been integrated into mobile platforms by developing a mobile application.

Tomato leaf curl New Delhi virus:an emerging plant begomovirus threatening cucurbit production

Tomato leaf curl New Delhi virus(ToLCNDV),a bipartite begomovirus,was first reported to infect tomato and has recently spread rapidly as an emerging disease to Cucurbitaceae crops.To date,the virus has been reported to infect more than 11 cucurbit crops,in 16 countries and regions,causing severe yield losses.In autumn 2022,ToLCNDV was first isolated from cucurbit plants in Southeastern coastal areas of China.Phylogenetic analysis established that these isolates belong to the Asian ToLCNDV clade,and shared high nucleotide identity and closest genetic relationship with the DNA-A sequence from the Chinese tomato-infecting ToLCNDV isolate(Accession no.OP356207)and the tomato New Delhi ToLCNDV-Severe isolate(Accession no.HM159454).In this review,we summarize the occurrence and distribution,host range,detection and diagnosis,control strategies,and genetic resistance of ToLCNDV in the Cucurbitaceae.We then summarize pathways that could be undertaken to improve our understanding of this emerging disease,with the objective to develop ToLCNDV-resistant cucurbit cultivars.

Molecular characterization and pathogenicity of an infectious clone of tomato leaf curl New Delhi virus isolate infecting Cucumis melo

Tomato leaf curl New Delhi virus(ToLCNDV)is a member of the genus Begomovirus,and causes devastating disease in the world.In recent years,ToLCNDV was rapidly spreading in China and induces severe economic losses in agriculture.In this study,we sequenced and characterized the complete genome of ToLCNDV isolates from melon plants showing leaf curling and stunting symptoms in Jiangsu Province of China.We constructed a full-length infectious cDNA clone of ToLCNDV,which could induce systemic infection with typical symptoms in Nicotiana benthamiana,Cit-rullus melo,and Citrullus lanatus plants through agrobacterium-mediated inoculation.Further experimental evidence demonstrated that the virions produced in plants infected with the infectious clone of ToLCNDV are biologically active and sap-transmissible.We also evaluated the resistance of commercial melon cultivars to ToLCNDV and found all testing melon cultivars were susceptible to ToLCNDV.Collectively,the reverse genetic system developed herein will facilitate further research on biological functions of proteins encoded by ToLCNDV and plant-ToLCNDV interactions,which might provide new insights into breeding resistance germplasm in crops.

Monoclonal Antibodies Against the Whitefly-Transmitted Tomato Yellow Leaf Curl Virus and Their Application in Virus Detection

Tomato yellow leaf curl virus（TYLCV）is a species of the family Geminiviridae,causing serious yield losses in tomato production.The coat protein（CP）gene of TYLCV isolate SH2 was expressed in Escherichia coli BL21（DE3）using pET-32a as the expression vector.The recombinant protein was purified through Ni＋-NTA affinity column and used to immunize BALB/c mice.Three hybridoma cell lines（2B2,2E3 and 3E10）secreting monoclonal antibodies（MAbs）against TYLCV CP were obtained by fusing mouse myeloma cells（Sp 2/0）with spleen cells from the immunized BALB/c mouse.The titers of ascitic fluids of three MAbs ranged from 10-6 to 10-7 in indirect-ELISA.Isotypes and subclasses of all the MAbs belonged to IgG1,κ light chain.Triple antibody sandwich enzyme-linked immunosorbent assay（TAS-ELISA）showed that the MAb 3E10 could react with five begomoviruses infecting tomato,while the other two（2B2 and 2E3）mainly reacted with TYLCV.TAS-ELISA was set up using the MAb 3E10,and the established method could successfully detect virus in plant sap at 1：2 560（w/v,g mL-1）.Detection of field samples showed that begomoviruses were common in tomato crops in Zhejiang Province,China.

Preliminary Study on Physiological Race Differentiation in Tomato Leaf Mold in Three Northeastern Provinces of China

Tomato leaf mold samples collected from tomato plants cultivated in plastic house in three northeastern provinces of China were studied by artifical spray inoculation at seedling stage,consulting Hubbcling physiological race differential hosts and adopting Day's classification system(1971).The results indicated that there were three races in these provinces;they were races 1,2,3,race 1,3 and race 3.Among them race 1,2,3 was the predominant.

Mapping and Candidate Gene Screening of Tomato Yellow Leaf Curl Virus Resistant Gene ty-5

To identify the inheritance pattern and perform fne mapping of ty-5 gene, P1, P2, F1, BC1 and F2 generations were obtained through a cross between CLN32120a-23 （containing ty-5 gene, P1） and S. lycopersicum Moneymaker （fully susceptible, P2）. The results showed that resistance of ty-5 gene was determined by a recessive effect. Meanwhile, it was presumed that another resistance gene might be involved in mediating the resistance to tomato yellow leaf curl virus （TYLCV）. In this study, fne mapping was used to map TYLCV resistance locus to an interval between NAC1 and TES2461 on the short arm of chromosome 4 with genetic distances of 0.5 and 0.8 cM, respectively. qRT-PCR results showed that four candidate genes, SlNAC1; LOC104229164; LOC101260925 and LOC101261508 having resistance-related expression patterns, were the likely target genes of ty-5. In addition, it was found that the codominant marker TES2461 could be used in marker-assisted selection （MAS） breeding. The fndings of this research provided the basis for future cloning of ty-5 gene as well as MAS breeding and plant resistance mechanism studies.

Development of high yield and tomato yellow leaf curl virus(TYLCV)resistance using conventional and molecular approaches:A review

Tomato(Solanum lycopersicum L.)belonging to the family Solanaceae is the second most consumed and cultivated vegetable globally.Since the ancient time of its domestication,thousands of cultivated tomato varieties have been developed targeting an array of aspects.Among which breeding for yield and yield-related traits are mostly focused.Cultivated tomato is extremely genetically poor and hence it is a victim for several biotic and abiotic stresses.Among the biotic stresses,the impact of viral diseases is critical all over tomato cultivating areas.Improvement of tomato still largely rely on conventional methods worldwide while molecular approaches,particularly Marker Assisted Selection(MAS)has become popular across the globe as a fast,low cost and precise tool which is essential in present day plant breeding.In this review paper,breeding tomato for high yield and viral disease resistance,particularly to tomato yellow leaf curl virus disease(TYLCVD)using conventional and molecular approaches will be discussed.Lining up of this set of information will be useful to those who are interested in tomato variety development with high yielding and TYLCVD resistance.

Diverse Regulations of Viral and Host Genes in Tomato Germplasms Responding to Tomato Yellow Leaf Curl Virus Inoculation

Tomato yellow leaf curl virus(TYLCV)is the dominating pathogen of tomato yellow leaf curl disease that caused severe loss to tomato production in China.In this study,we found that a TYLCV-resistant tomato line drastically reduced the accumulation of viral complementary-sense strand mRNAs but just moderately inhibited that of viral DNA and virion-sense strand mRNAs.However,two other resistant lines did not have such virus inhibition pattern.Analysis of differential expressed genes showed that the potential host defense-relevant processes varied in different resistant tomatoes,as compared to the susceptible line,suggesting a diversity of tomato TYLCV-resistance mechanisms.

Characterization and function of Tomato yellow leaf curl virus-derived small RNAs generated in tolerant and susceptible tomato varieties

supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China （20134320120013）;the Natural Science Foundation of Hunan Province, China （14JJ3095）

Evaluation of Tomato Lines against Septoria Leaf Spot under Field Conditions and Its Effect on Fruit Yield

Field studies were conducted at Hazara Agriculture Research Station, Abbottabad to evaluate thirteen AVRDC lines along with one commercial check (Roma) for potential of fruit yield against septoria leaf spot during summer season 2014. The disease established itself by natural infection and disease severity was estimated with the help of 0 - 5 disease rating scale after 15 days interval from the onset of symptoms. The lines showed significant difference in % septoria leaf spot infection. The disease severity % increased up to 100% in line AVTO1314 whereas the lowest % severity was recorded in AVTO1173 which showed the highest yield (468.1 g) with average fruit weight 122.22 g while the significantly lowest mean yield/plant (35.05 g) was calculated in line AVTO1314 with fruit weight 47.92 g. It was concluded that the line AVTO1173 could be useful in genetic programs for incorporating resistant genes in local tomato germplasm against septoria leaf spot disease.

The Yield and Diseases-Pest Performance of Breeding Materials for Tomatoes (Lycopersicon esculentum) Sourced from Different Exotic Sources

A study was conducted with 36 tomato germplasm [PGRC (19), The Netherlands (7), Japan (2), and Bangladesh (9)] with 3 check varieties in the research field of the Olericulture Division of Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Gazipur during the winter season of 2022-23 to identify promising tomato breeding germplasm. All the germplasm showed differences in most of the parameters studied. Considerable variation was observed for fruit yield per hectare varied from 39 to 144 tons, while the highest fruit yield per hectare was harvested from the germplasm viz., BD 7759B, BD 7757, BD 7751, BD 7301, QM, BD 7759A, BD 7762, QF, BD 7753, BD 8886, BD 10351, NL-1A, SLA-19. The number of locules, total soluble solids (TSS) and plant height at last harvest varied from 2 to 6.6, 2.6 to 5.9%, and 66 to 154cm, respectively. The TYLCV infection (%) and leaf-sucking pest infestation (%) were observed with a 1 to 20% range in the field condition in both cases. So, we can select that germplasm has zero per cent infestation. Considering the plant growth habit, earliness, different yield contributing horticultural traits, virus and pest infestation thirteen germplasm viz., BD 7759B, BD 7757, BD 7751, BD 7301, QM, BD 7759A, BD 7762, QF, BD 7753, BD 8886, BD 10351, NL-1A, SLA-19 were selected as breeding materials for further tomato improvement program.

Socio-Economic and Scientific Impact Created by Whitefly-Transmitted,Plant-Virus Disease Resistant Tomato Varieties in Southern India

Research carried out to assess the impact of open-pollinated Tomato leaf curl virus（ToLCV）-resistant tomatoes and hybrids on the livelihoods of resource-poor farmers in Southern India is described and discussed.Three high-yielding ToLCV-resistant tomato varieties were developed initially using conventional breeding and screening techniques involving inoculation by ToLCV-viruliferous whitefly,Bemisia tabaci.In 2003 and 2004,respectively,these varieties were released officially by the Karnataka State Seed Committee and the Indian Ministry of Agriculture through notification in the Gazette of India.From 2003 to 2005,eleven seed companies bought breeder seed of the ToLCV-resistant varieties and used them to begin breeding F1 hybrids from them.Socio-economic studies carried out to assess the benefits obtained from growing the ToLCV-resistant varieties found that farmers could gain up to 10 times the profit by growing the ToLCV-resistant varieties compared to the pre-existing ToLCV-susceptible varieties.Adoption of ToLCV-resistant tomatoes was also associated with reduced pesticide use.Extra income from tomato sales was prioritised by farmers to pay for children＇s education,better nutrition and medicines.In a joint effort with the commercial seed sector in India,a promotional field day was organised in 2007.As well as the three ToLCV-resistant varieties,62 ToLCV-resistant hybrid tomatoes were exhibited during a farmer-field day by 17 commercial seed companies and several public institutes.Tomatoes with ToLCV-resistance are now grown widely in South India and seeds of the three open-pollinated varieties have been distributed to more than 12 countries.In 2007,a conservative estimate of the financial-benefit to cost of the research ratio was already more than 837：1.

Effect of Anti-nematode Preparations on Physiological Traits of Tomato Leaves Affected by Root-knot Nematode

[ Objective ] The paper was to study the effects of anti-nematode preparations with different mechanisms on changes of enzyme systems and membrane permeability of tomato leaves, so as to provide reference basis for effective control of soil root-knot nematode in greenhouse. [ Method] With tomato seedlings af- fected by root-knot nematode as material, changes of superoxide dismutase（SOD）, peroxidase（ POD）, relative conductivity and malondialdehyde （MDA） in toma- toes were tested after the seedling soil was treated by preparations of Wuxianmei, Hailvsu, Duxiandna and Avermectin. [ Result] After treated by different prepara- tions, SOD and POD activity of tomato leaves were higher than control, and that treated by Wuxianmei was the highest. In addition to Duxiandna, the relative con- ductivity and MDA content of other treatments were significantly lower than control. When tomatoes were planted for 70 d, the effect of Avermectin against reot-knot nematode Was the best of 66.3%. [ Conclusion] After tomatoes were infected by root-knot nematode, different preparation treatments all had certain control effect, which made the physical indicators of tomato have obvious change. Integrated control of multiple preparations in greenhouse was beneficial to control soil root-knot nematode.

Markers for Rapid Evaluation of Virus Resistance for TYLCV in Tomato, ZYMV and PRSV-W in Zucchini and LMV in Lettuce and Hybrid Seeds in Pumpkin

Screening for the source of virus resistance in horticultural plants or specific characterization as hybridization, through symptoms, requires time and depends on the weather and knowledge of plant characteristics. So, it is important to develop specific gene markers to allow rapid diagnosis by PCR. Markers were developed based on sequences homology comparison of susceptible and resistant plants provided by HORTEC SEEDS in tomato for Tomato yellow leaf curl virus (TYLCV) by the resistance gene Ty-1, in zucchini for Zucchini yellow mosaic virus (ZYMV) and Papaya ringspot virus estirpe watermelon (PRSV-W), and in lettuce for Lettuce mosaic virus (LMV). Fragments of 249 bp were amplified only by resistant plants to TYLCV as the hybrids 2648 and Aguamiel, and not for varieties as Santa Cruz or Carina. It were observed for ZYMV the amplification of 791 bp by the resistant hybrid Px7051 and not for the susceptible cultivar La Belle;for PRSV-W using the same zucchini plants the amplification of 650 bp for susceptible and 750 bp for resistant;for LMV the 421 bp amplification only for the resistant cultivar Brasil 303 and not for susceptible Babá de Verão. Finally, it was observed that primers PK47F/R were able to check the Cabotiá seed hybrids of pumpkin Jabras.

基于高光谱成像技术的番茄叶片含水量检测研究

[目的]为快速检测叶片含水量,本研究探索及时监测番茄植株生长状况的在线监测模型。[方法]利用高光谱成像技术,提取195个叶片样本的平均光谱反射率。通过异常值剔除、样本集划分、5种预处理方法对原始光谱进行预处理和优化,采用连续投影算法(successive projections algorithm,SPA)、无信息变量消除变换法(uninformation variable elimination,UVE)、迭代保留信息变量法(iterative retained information variable,IRIV)和遗传偏最小二乘算法(genetic partial-least-squares algorithm,GAPLS)提取特征波长,并建立偏最小二乘回归(partial-least-squares regression,PLSR)模型。基于优选的特征波长,建立PLSR、多元线性回归(multiple linear regression,MLR)以及主成分回归(principal component regression,PCR)模型和卷积神经网络模型(convolutional neural network,CNN)。[结果]优选基线校准-正交信号校正法(baseline-orthogonal signal correction,Baseline-OSC)对叶片含水量进行预处理;IRIV法提取的特征波长建立的叶片含水量定量预测模型效果最优,R_(c)^(2)为0.489,R_(p)^(2)为0.466;基于IRIV-CNN建立的叶片含水量模型效果好(R^(2)c=0.668,RMSEC=0.019;R_(p)^(2)=0.424,RMSEP=0.033)。[结论]利用高光谱成像技术结合Baseline-OSC-IRIV-CNN模型预测番茄叶片含水量是可行的。

Evaluation of Growth Area Foliar Red Tomato Crop Using Markov Chains

The importance of evaluating the leaf area in red tomato plants aims to determine the growth and development of crops established two production cycles, spring-summer and autumn-winter to compare the influence of temperature on the growth of leaf area. Repeated, weekly samples were taken by identifying the week and determining the growth and leaf area development using Markov chains, using an array of transition to describe and represent in a flowchart the finite number of physiological States. With the analysis in the steady state process and applying the equations of odds, we get that leaf area growth is established from the seventh week shown in the first cycle (C1) with the chance of 0.266, 0.264 and 0.263, in the last two weeks. It was observed an increase of 6% in the cycle autumn-winter cycle compared spring-summer.

果型和抗性基因协同对番茄黄化曲叶病毒带毒量的影响

以12份番茄种质为试材,其具有2类果实大小和3种不同抗性基因,通过检测番茄黄化曲叶病毒病田间抗性和带毒量指标,探索果实大小、抗病基因与田间抗性、带毒量之间的关系。结果显示,在自然传毒情况下,所有番茄材料都能检测到病毒感染。在番茄定植后28 d,小果型番茄M8(I)、M5(I)、M3(I)、M7(I)、M9(I)和M11(HR)带毒量均较低,大果型番茄M6(S)、M10(S)、M4(S)和M2(S)带毒量均较高,且小果型番茄田间发病率明显低于大果型番茄。除了Ty-1/ty-1单基因抗性不受番茄果实大小影响外,携带其他单基因或聚合基因抗性的番茄种质均与果实大小有关。在此节点上,带毒量越高抗性越弱,带毒量越低抗性越强。总体来说,在遭受番茄黄化曲叶病毒侵染时,小果型番茄田间抗性强于大果型番茄。

新德里番茄曲叶病毒的发生危害及阻截防控措施

新德里番茄曲叶病毒(Tomato leaf curl New Delhi virus,ToLCNDV)属双生病毒科,菜豆金色花叶病毒属,是近年来新发现的一种可侵染多种重要蔬菜、观赏植物、杂草和野生植物的病原物。1995年ToLCNDV首次在印度番茄上被报道,随后在巴基斯坦等亚洲国家发生危害,2012年以后传至西班牙等欧洲国家。我国首次于2010年在台湾地区报道了ToLCNDV。本文在收集相关资料的基础上,概述了该病毒的发生、分布与危害、分子特征、寄主范围、危害症状、传播方式和复合侵染现象,并提出了相应的阻截防控建议,以防范ToLCNDV在我国的传播扩散和危害。