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.

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.

Investigation of the mechanism of adult-stage resistance to barley yellow dwarf virus associated with awheat-Thinopyrum intermedium translocation

Barley yellow dwarf virus(BYDV)can infect wheat(Triticum aestivum L.),leading to yield loss.Among four BYDV strains(GAV,GPV,PAV,and RMV)identified in China,BYDV-GAV is the prevailing isolate.YW642,a wheat–Thinopyrum intermedium translocation line,is resistant to BYDV isolates at both seedling and adult stages.Zhong 8601 is the wheat recurrent parent of YW642 and is susceptible to BYDV.In this study,we investigated the adult-stage resistance mechanism of YW642,measured BYDV titer and hydrogen peroxide(H_2O_2) in adult-stage leaves of YW642 and Zhong 8601 inoculated with BYDV-GAV,and identified transcriptional differences between YW642 and Zhong 8601 using microarray-based comparative transcriptomics.Enzyme-linked immunosorbent assay and H_2O_2assay showed that both BYDV titer and H_2O_2 content were markedly lower in YW642 than in Zhong 8601 at 21,28,35,and 40 days post-inoculation(dpi).The transcriptomic comparison revealed that many types of genes were significantly up-regulated at 35 dpi in adult-stage leaves of YW642 compared to Zhong 8601.The important up-regulated genes associated with the adult-stage resistance encoded 15 resistance-like proteins,pathogenesis-related proteins(such as defensin and lipid transfer proteins),protein kinase homologs,transcription factors,reactive oxygen species scavenging-related proteins,and jasmonic acid and gibberellic acid biosynthesis enzymes.These results suggest that precise expression regulation of these proteins plays a crucial role in adult-stage resistance of YW642 against BYDV infection.

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.

TaRAR1 is Required for Lr24-Mediated Wheat Leaf Rust Resistance

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. RT- PCR 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.

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。

小麦黄花叶病抗性研究及育种应用进展

小麦黄花叶病是一种全球性的土传病毒病,严重时会导致小麦产量大幅下降。小麦黄花叶病毒(WYMV)是主要的病原体之一,属于马铃薯Y病毒科(Potyviridae)大麦黄花叶病毒属(Bymovirus),以禾谷多黏菌(Polymyxa graminis)为媒介感染小麦。目前已鉴定出14个抗WYMV的基因位点,图位克隆了1个抗病基因,证实了3个基因具有抗病性调控功能,已育成多个抗病小麦品种(系)。本文从小麦黄花叶病毒的病原体特性、病害分布、小麦抗性遗传和抗病育种等方面,综述了WYMV及小麦抗病性的研究进展,并对WYMV抗性基因挖掘和小麦抗病育种应用进行了展望。

基于DNA-BSA重测序和SSR技术的番茄ty-5基因分子标记的筛选

利用DNA-BSA重测序和SSR标记技术对番茄黄化曲叶病毒抗病基因ty-5开展定位研究。DNA-BSA重测序获得7个与番茄ty-5基因相关的侯选区域,分别位于1,4,9号染色体上,总长度为21.68Mb。利用SSR标记获得C_2at4g34700和SSR383标记,与番茄抗黄化曲叶病毒病基因ty-5紧密连锁,并且没有发现重组单株。最后,对DNA-BSA重测序和SSR标记结果联合分析,标记C_2at4g34700和SSR383位于重测序关联分析的1号和9号染色体的抗病关联区域附近。由此初步认定,这2个标记可以作为番茄抗黄化曲叶病毒病ty-5基因的分子标记。

青稞种质资源抗条纹病鉴定及抗病基因分子检测

【目的】为发掘更多的抗条纹病青稞种质资源,明确抗条纹病基因在青稞种质资源中分布状况。【方法】选用127份青稞种质资源,利用2个菌株室内人工接种方法进行抗病性鉴定和评价,并利用3个已知抗条纹病基因的SSR分子标记引物进行检测。【结果】127份资源中综合抗病表现免疫、高抗、中抗、高感和中感的分别有13、26、19、52和17份,分别占鉴定材料总数10.24%、20.47%、14.96%、40.94%和13.39%。Rdg基因分子标记检测结果表明,可能携带Rdg1a、Rdg2a和Rdg3的青稞种质资源数分别有3、40和11份,分别占供试材料的2.36%、31.50%和8.66%。【结论】‘青0027’可能同时含有Rdg2a和Rdg3这2个抗性基因。

和田地区设施番茄抗黄化曲叶病毒病的比较试验

为筛选出和田地区设施番茄高抗黄化曲叶病毒病品种,为设施番茄黄化曲叶病毒病的防治及抗病品种的选择提供依据。结果表明,供试品种均发现不同程度的黄化曲叶病毒侵染,番茄品种间株高、茎粗和叶片数随着黄化曲叶病毒发病率和病情指数的增加而呈下降趋势。叶绿素相对含量(SPAD值)、叶片净光合速率(Pn)和产量以特美特36号最高,与优拉578和东风199差异不显著,但显著高于其他处理。品种戴安娜、优拉578、东风199、澳粉1号、芬娜和艾利斯相对抗病指数为0.86~0.99,为高抗品种。从抗病性、植株性状、叶片光合参数和产量等指标进行综合分析,以品种特美特36号、东风199和优拉578表现较好,可作为新疆和田地区设施秋茬番茄抗黄化曲叶病毒病首选品种。

The novel C5 protein from tomato yellow leaf curl virus is a virulence factor and suppressor of gene silencing

Tomato yellow leaf curl virus(TYLCV)is known to encode 6 canonical viral proteins.Our recent study revealed that TYLCV also encodes some additional small proteins with potential virulence functions.The fifth ORF of TYLCV in the complementary sense,which we name C5,is evolutionarily conserved,but little is known about its expression and function during viral infection.Here,we confirmed the expression of the TYLCV C5 by analyzing the promoter activity of its upstream sequences and by detecting the C5 protein in infected cells by using a specific custom-made antibody.Ectopic expression of C5 using a potato virus X(PVX)vector resulted in severe mosaic symptoms and higher virus accumulation levels followed by a burst of reactive oxygen species(ROS)in Nicotiana benthamiana plants.C5 was able to effectively suppress local and systemic post-transcriptional gene silencing(PTGS)induced by single-stranded GFP but not double-stranded GFP,and reversed the transcriptional gene silencing(TGS)of GFP.Furthermore,the mutation of C5 in TYLCV inhibited viral replication and the development of disease symptoms in infected plants.Transgenic overexpression of C5 could complement the virulence of a TYLCV infectious clone encoding a dysfunctional C5.Collectively,this study reveals that TYLCV C5 is a pathogenicity determinant and RNA silencing suppressor,hence expanding our knowledge of the functional repertoire of the TYLCV proteome.

Spotted-Leaf Mutants of Rice(Oryza sativa)

Many rice spotted-leaf （spl） mutants are ideal sources for understanding the mechanisms involved in blast resistance, bacterial blight resistance and programmed cell death in plants. The genetic controls of 50 spotted-leaf mutants in rice have been characterized and a few spotted-leaf genes have been isolated as well. This article reviews the odgin, genetic modes, isolation and characterization of spotted-leaf genes responsible for their phenotypes, and their resistance responses to main rice diseases.

Genome-wide identification and expression analysis of GDSL esterase/lipase genes in tomato

The GDSL esterase/lipase family contains many functional genes that perform important biological functions in growth and development, morphogenesis, seed oil synthesis, and defense responses in plants. The expression of GDSL esterase/lipase genes can respond to biotic and abiotic stresses. Although GDSL esterase/lipase family genes have been identified and studied in other plants, they have not been identified and their functions remain unclear in tomato. This study is the first to identify 80 GDSL esterase/lipase family genes in tomato, which were named SlGELP1–80. These genes were mapped to their positions on the chromosomes and their physical and chemical properties, gene structure, phylogenetic relationships, collinear relationships, and cis-acting elements were analyzed. The spatiotemporal expression characteristics of the Sl GELP genes in tomato were diverse. In addition, RNA-seq analysis indicated that the expression patterns of the SlGELP genes in tomato differed before and after inoculation with Stemphylium lycopersici. qRT-PCR was used to analyze the expression of five Sl GELP genes after treatments with S. lycopersici, salicylic acid and jasmonic acid. Finally, this study was the first to identify and analyze GDSL esterase/lipase family genes in tomato via bioinformatics approaches, and these findings provide new insights for improving the study of plant disease resistance.

Research Progress of Wheat Yellow Mosaic

Wheat yellow mosaic is a soil-borne virus disease,and now has become one of the main viral diseases endangering wheat production in China,posing serious threat to wheat production. The pathogen,transmission media,incidence regularity and performance of wheat yellow mosaic were introduced in the paper,and its molecular biology and breeding research were summarized,in order to provide a reference for resistance breeding and production practice of wheat yellow mosaic.

Science Letters:Expression of a begomoviral DNAβ gene in transgenic Nicotiana plants induced abnormal cell division

An increasing number of monopartite begomoviruses are being identified that a satellite molecule (DNAβ) is required to induce typical symptoms in host plants. DNAβ encodes a single gene (termed βC1) encoded in the complementary-sense. We have produced transgenic Nicotiana benthamiana and N. tabacum plants expressing theβC1 gene of a DNAβ associated with Tomato yellow leaf curl China virus (TYLCCNV), under the control of the Cauliflower mosaic virus 35S promoter. Transgenic plants expressing βC1 showed severe developmental abnormalities in both species. Microscopic analysis of sections of both transgenic and non-transgenic N. tabacum leaves showed abnormal outgrowths of transgenic N. tabacum to be due to disorganized cell division (hyperplasia) of spongy and palisade parenchyma. Immuno-gold labeling of sections with a polyclonal antibody against the βC1 protein showed that the βC1 protein accumulated in the nuclei of cells. The possible biological function of the βC1 protein was discussed.

39份外引小麦种质的抗叶锈病基因检测及其抗性鉴定

为明确39份外引小麦种质的抗叶锈病基因组成,利用与抗病基因紧密连锁或共分离的分子标记对抗叶锈病基因进行检测,并结合田间接种鉴定对种质材料的叶锈病抗性进行评价。结果表明,抗叶锈病基因Lr1、Lr10、Lr20、Lr24、Lr26、Lr34、Lr37和Lr38在39份种质中均有分布,频率分别为30.77%、17.95%、2.56%、5.13%、12.82%、30.77%、23.08%和5.13%,其中携带Lr24和Lr38的种质抗性良好。Lr34和Lr37单独存在时,种质对叶锈病的抗性分别表现为中感和高感,两者聚合时能够提高载体种质的抗性水平,表现为中抗。此外,4份种质材料(KPL-1、OK.95571、莫斯科39和非黑土地24)对叶锈病的抗性表现突出,均达到0;级,是抗叶锈病育种的重要抗源,其中KPL-1和OK.95571分别携带3个和5个抗叶锈病基因;莫斯科39和非黑土地24仅携带Lr1,推测这两份材料含有其他未检测的抗叶锈病基因。综上,较多的抗叶锈病基因聚合有利于提高种质的叶锈病抗性。

海南地区冬春作甜瓜病毒病病原鉴定与分析

为探明海南地区冬春作甜瓜病毒病的主要病原种类和危害情况,2022—2023年冬春季从海南甜瓜主产区采集34份疑似感染病毒病的甜瓜样品,利用高通量测序(high-throughput sequencing)和聚合酶链式反应(polymerase chain reaction,PCR)技术对甜瓜病毒病的病原种类进行鉴定和分析。结果表明:甜瓜黄斑病毒(melon yellow spot virus,MYSV)、西瓜银斑驳病毒(watermelon silver mottle virus,WSMo V)和中国南瓜曲叶病毒(squash leaf curl China virus,SLCCNV)引起的甜瓜病毒病在海南多个产区普遍发生。其中,MYSV检出率最高,为73.53%;其次为WSMo V,检出率61.76%;且呈现MYSV和WSMo V复合侵染现象,复合侵染率为47.06%。

美味樱桃番茄新品种“粉仙”的选育

“粉仙”番茄是通过双亲杂交育成杂交一代番茄新品种。母本“FQYH26”是由“粉贝贝”商品种经过10代自交分离、定向选择而获得的优良自交系,父本“YHFQ64”是由“贝丝”商品种经过12代分离、纯化,筛选出性状稳定的优良单株。该品种属于无限生长型粉色小果番茄,早熟,植株长势强,抗病性强,产量高,果实均匀,果色亮丽,果型椭圆形,单果质量在15~20 g,可溶性固形物含量7.2%,维生素C含量0.27 mg·g^(-1),番茄红素含量0.13 mg·g^(-1),番茄红素是普通番茄的10倍以上。“粉仙”品种抗黄化曲叶病毒、黄瓜花叶病毒、烟草花叶病毒、枯萎病和根结线虫病。田间丰产性好,适宜山东、河南、河北、辽宁、内蒙古等进行早春保护地及越冬温室栽培,2020年1月通过国家非主要农作物品种登记,登记号为GPD番茄(2019)370374。

四川省育成小麦品种和高代品系对条锈病的抗病性评价

四川省不仅是条锈菌冬繁区,也是我国东部麦区重要的春季初侵染菌源地和毒性变异地。准确评价四川小麦新育成品种和高代品系对条锈病的抗性水平,能为合理培育和使用抗病品种提供重要依据。利用当前条锈菌优势小种和4个地点的成株期鉴定圃对来自四川省的115份小麦育成品种和299份高代品系进行苗期和成株期抗病性鉴定。结果表明,新育成品种苗期对优势小种的高抗CYR32、CYR33和CYR34的比例发生不同程度的变化,对CYR32的高抗比例为40.9%、对CYR34的高抗比例为17.4%,而供试高代品系高抗比例从52.3%降至46.2%;中抗类型育成品种从20.0%增加到40.9%,高代品系从19.6%增加至33.2%。表明条锈菌优势小种更替后一些材料仍保留了部分抗性,后期选育的高代品系兼顾对新小种的抗病性。育成品种在四川成都和甘肃清水成株期鉴定,高抗品种所占比例较低,分别为13.9%和3.5%,但高代品系高抗类型比例较高,分别为42.2%和8.5%,表明甘肃和四川条锈菌的致病类型和发病环境条件存在较大差异,近年来四川小麦成株抗条锈病育种取得显著进展。