Changes in concentrations and transcripts of plant hormones in wheat seedling roots in response to Fusarium crown rot

Fusarium crown rot(FCR) is a soilborne disease causing severe yield losses in many wheat-growing areas of the world. Diseased plants show browning and necrosis of roots and stems causing white heads at maturity. Little is known about the molecular processes employed by wheat roots to respond to the disease. We characterized morphological, transcriptional and hormonal changes in wheat seedling roots following challenge with Fusarium pseudograminearum(Fp), the main pathogen of FCR. The pathogen inhibited root development to various extents depending on plants' resistance level. Many genes responsive to FCR infection in wheat roots were enriched in plant hormone pathways. The contents of compounds involved in biosynthesis and metabolism of jasmonic acid, salicylic acid, cytokinin and auxin were drastically changed in roots at five days post-inoculation. Presoaking seeds in methyl jasmonate for 24 h promoted FCR resistance, whereas presoaking with cytokinin 6-benzylaminopurine made plants more susceptible. Overexpression of TaOPR3, a gene involved in jasmonic acid biosynthesis, enhanced plant resistance as well as root and shoot growth during infection.

Integrated transcriptome and metabolite profiling highlights the role of benzoxazinoids in wheat resistance against Fusarium crown rot

Fusarium crown rot(FCR), caused by Fusarium spp., is a chronic and severe plant disease worldwide. In the last years, the incidence and severity of FCR in China has increased to the point that it is now considered a threat to local wheat crops. In this study, for the first time, the metabolites and transcripts responsive to FCR infection in the partial resistant wheat cultivar 04 Zhong 36(04 z36) and susceptible cultivar Xinmai 26(XM) were investigated and compared at 20 and 25 days post inoculation(dpi). A total of 443 metabolites were detected, of which 102 were significantly changed because of pathogen colonization.Most of these 102 metabolites belonged to the flavonoid, phenolic acid, amino acid and derivative classes.Some metabolites, such as proline betaine, lauric acid, ribitol, and arabitol, were stably induced by Fusarium pseudograminearum(Fp) infection at two time points and may have important roles in FCR resistance. In line with the reduced seedling height of 04 z36 and XM plants, RNA-seq analysis revealed that FCR infection significantly affected the photosynthesis activities in two cultivars. Furthermore, 15 jasmonate ZIM-domain genes(JAZ) in the significantly enriched ‘regulation of jasmonic acid mediated signaling pathway’ in 04 z36 were down-regulated. The down-regulation of these JAZ genes in 04 z36 may cause a strong activation of the jasmonate signaling pathway. Based on combined data from gene expression and metabolite profiles, two metabolites, benzoxazolin-2-one(BOA) and 6-methoxy-benzoxazolin-2-one(MBOA), involved in the benzoxazinoid-biosynthesis pathway, were tested for their effects on FCR resistance. Both BOA and MBOA significantly reduced fungal growth in vitro and in vivo, and, thus, a higher content of BOA and MBOA in 04 z36 may contribute to FCR resistance. Above all, the current analysis extends our understanding of the molecular mechanisms of FCR resistance/susceptibility in wheat and will benefit further efforts for the genetic improvement of disease resistance.

Identification of proteins associated with Fusarium crown rot resistance in wheat using label-free quantification analysis

Fusarium crown rot(FCR),typically caused by Fusarium pseudograminearum,is a severe soil-borne disease that,in recent years,has become an emerging threat to Chinese wheat crops.For the first time in this study,we investigated and compared the proteomic characteristics of two Chinese wheat varieties(04 Zhong 36 and Xinmai 26)at 24,48,and 72 h post-inoculation using label-free quantitative proteomic analysis.A total of 9234 proteins were successfully quantified,of which 783 were differentially expressed after inoculation.These proteins were mainly involved in metabolic,single-organism,and cellular processes.Thirty-three proteins associated with defense,cell wall formation,photosynthesis,etc.,showed consistently different expression between the two genotypes at multiple time points.In particular,chitinase,which degrades chitin in the fungal cell wall and limits fungal growth,was exclusively and consistently upregulated in 04 Zhong 36 across the three time points.Other proteins such as flavonoid O-methyltransferase,glycosyltransferase,and peroxidase were only upregulated in 04 Zhong 36,and proteins,including the berberine bridge enzyme and rubisco large subunit-binding protein,were specifically downregulated in Xinmai 26.The expression of transcripts encoding eight selected proteins through qRT-PCR analysis supported the proteomic profiles.Overall,the results of this study allow us to understand FCR resistance in wheat at the protein level.Some proteins and their corresponding genes may be useful resources for the genetic improvement of FCR resistance in wheat.

Genetic Diversity of Fusarium solani f. sp. cucurbitae, the Causal Root and Crown Rot of Cucurbits (Melon) by Using Molecular Markers and Control

Detection of F. solani f. sp. cucurbitae causal agent of the crown and root rot disease of melon race 1, race 2 is difficult. It is based only on morphological characteristic. In this study, forty isolates identified as Fusarium solani based on morphological characterization, F. solani was one of the most frequently isolated species. Molecular identification of these isolates by PCR technique using species-specific primer, indicated that thirty-two isolates, amplified product 580 bp (race 1) and two isolate amplified product 580 bp (race 2), while six isolates were not amplified with primer of both races. Production of Trichothecenes (T2-toxen, DON.) by Fusarium solani was conducted on isolates confirmed as belonging in the F. solani by PCR. The results indicated that the presence of Tri5, Tri13 genes is coding the ability of synthesis mycotoxin. In vitro, the results indicated that NPs (AgNPs, MgNPs) and chemical (Phylex) possess the antifungal properties against at various level. Treatment with (AgNPs 150 ppm, MgNPs 2%, 3% ppm) and 3% Phylex resulted in maximum inhabitation of F. solani . In vivo, five characters (height plant, hoot ant root fresh and dry weight) were measured based on the greenhouse, field experimental results. Treatment with (AgNPs, MgNPs) and Phylex had higher measured parameters than positive control.

Delineating a locus conferring Fusarium crown rot resistance on chromosome arm 1HL in barley by developing and analysing a large population derived from near isogenic lines

Fusarium crown rot(FCR),a chronic and severe disease caused by various Fusarium species,is prevalent in semi-arid cropping regions worldwide.One of the major QTL conferring FCR resistance was detected on chromosome arm 1 HL(Qcrs.cpi-1 H)in barley.To develop markers that can be reliably used to incorporate the resistance locus into breeding programs,we developed and assessed a near-isogenic line-derived population consisting of1180 recombinant inbred lines targeting the locus.Using this population,we delineated Qcrs.cpi-1 H into an interval of 0.4 c M covering a physical length of about 487 kb.Six markers co-segregating with this locus were generated.Co-linearity for genes located in this interval between the genome of barley and those of either rice or Brachypodium distachyon is poor.Three genes with non-synonymous variations between the resistant and susceptible lines were identified within the interval.The results reported in this study not only provide markers for integrating Qcrs.cpi-1 H into breeding programs,but also form a solid foundation for cloning the causal gene(s)underlying this locus.

Pathogen Identification of Wheat Crown Rot and Control Effects of Different Fungicides

[ Objectives ] The paper aimed to reduce the damage of wheat crown rot caused by Fusarium graminearum on wheat production. [ Methods ] Pathogens were isolated from wheat crown rot samples collected in fields, and the major pathogenic fungi were determined as F. graminearum through molecular techniques. Different fungicides were administrated at seedling stage and reviving stage to control the disease. [ Results] There were significant differences in control effects against crown rot among different fungicides. Tebuconazole ·prochloraz mixture and Carbendazim · triadimefon mixture had good control effects, while such single agents as Tebuconnazole and Difenoconazole· propicondzole had good control effects as well. [ Conclusions] Seed dressing with agents could significantly reduce the incidence rate of crown rot at seedling stage, and stem spraying at reviving stage had better control effect.

Elimination of the yellow pigment gene PSY-E2 tightly linked to the Fusarium head blight resistance gene Fhb7 from Thinopyrum ponticum

Fhb7 is a major gene that was transferred from Thinopyrum ponticum to chromosome 7D of wheat(Triticum aestivum)and confers resistance to both Fusarium head blight(FHB)and Fusarium crown rot(FCR).However,Fhb7 is tightly linked to the PSY-E2 gene,which causes yellow flour,limiting its application in breeding.To break this linkage,marker K-PSY was developed for tagging PSY-E2 and used with Fhb7 markers to identify recombination between the two genes.Screening 21,000 BC1F2 backcross progeny(Chinese Spring ph1bph1b*2/SDAU 2028)revealed two Fhb7^(+)wheat-Tp7el_(2)L lines,Shannong 2–16and Shannong 16–1,that carry a desired truncated Fhb7^(+)translocation segment without PSY-E2.The two lines show levels of resistance to FHB and FCR similar to those of the original translocation line SDAU 2028,but have white flour.To facilitate Fhb7 use in wheat breeding,STS markers were developed and used to isolate Fhb7 on a truncated Tp7el_(2) translocation segment.Near-isogenic lines carrying the Fhb7^(+)segment were generated in the backgrounds of three commercial cultivars,and Fhb7^(+)lines showed increased FHB and FCR resistance without yield penalty.The breakage of the tight linkage between Fhb7 and PSY-E2 via homoeologous recombination provides genetic resources for improvement of wheat resistance to FHB and FCR and permit the large-scale deployment of Fhb7 in breeding using marker-assisted selection.

种衣剂防治小麦茎基腐病效果的评价

茎基腐病已成为黄淮小麦主产区最具破坏性的土传病害之一,对我国粮食安全供给构成严重威胁。目前抗茎基腐病主栽品种稀少,生产上主要依赖于化学农药措施。药剂拌种可以有效防治茎基腐病。综合评价现有的种衣剂对小麦茎基腐病的防治及增产效果,以期为合理用药提供依据。采取高感茎基腐病小麦品种郑麦1354为研究对象,播种前种子包衣晾干,利用高致病力茎基腐病菌株PY20-20培养小米菌谷,连续2个小麦生长季利用进行人工接种病圃,包衣种子和接种菌谷等重量混合播种,分别于小麦拔节期和乳熟期记载处理小区植株发病情况,调查9种种衣剂处理后不同生育期的病情指数(disease index,DI),成熟收获后测定小区实际产量,结合小麦产量相关性状,比较种衣剂防病增产作用。结果表明:种衣剂处理后拔节期茎基腐病DI值均小于1.0,显著小于空白对照(5.07),防治效果为85.09%~100%,其中33 g·L^(-1)咯菌·噻虫胺、9%苯甲·吡虫啉和35 g·L^(-1)精甲霜灵·咯菌腈的防效达到为97%~100%。在乳熟期,种衣剂处理后茎基腐病DI平均值低于15,显著小于空白对照(81.55),其中35 g·L^(-1)精甲霜灵·咯菌腈和9%苯甲·吡虫啉防效较好,平均防效分别达到92%和95%,而且分别增产39.62%和36.31%。综合而言,采用种衣剂35 g·L^(-1)精甲霜灵·咯菌腈和9%苯甲·吡虫啉防治小麦茎基腐病效果好且增产效果显著,具有较好的应用前景。

小麦茎基腐病抗性位点研究进展

对小麦茎基腐病(FCR)抗性位点研究进行综述。目前,在小麦所有的21条染色体上定位了140个抗性QTL,含10个抗性基因,虽然报道的抗性位点很多,但主效位点不明确,严重影响小麦FCR抗性改良进程。分析了小麦FCR抗性位点研究中的主要问题,提出了统一抗性鉴定标准、增强成株期抗性研究等建议,以明确抗FCR主效位点/基因并开发分子标记,通过分子标记辅助选择促进FCR抗性改良进程。

自噬相关基因FpAtg3参与假禾谷镰孢的生长和致病

【背景】假禾谷镰孢(Fusarium pseudograminearum)引起的小麦茎基腐病是我国小麦生产上的新病害。自噬是真核生物中普遍发生的细胞过程,调控多种植物病原真菌的生长发育和侵染,但其在假禾谷镰孢中的作用还不明确。【目的】明确假禾谷镰孢自噬相关基因FpAtg3在该病菌生长和致病中的作用,解析假禾谷镰孢致病机理,为小麦茎基腐病科学防控提供理论依据。【方法】从NCBI数据库中下载主要真菌的Atg3氨基酸序列,利用MEGA5.05构建系统进化树。利用Split-PCR策略构建FpAtg3基因敲除盒,经PEG介导的原生质体转化导入假禾谷镰孢野生型菌株中。利用潮霉素抗性筛选阳性转化子,并经PCR检测获得FpAtg3基因缺失突变体(ΔFpAtg3)。构建pKNTG-FpAtg3重组载体,导入ΔFpAtg3菌株,利用FpAtg3自身启动子启动FpAtg3的转录,以获得FpAtg3缺失突变体的回补菌株。利用假禾谷镰孢营养生长的培养基PDA、CM和MM测定菌丝生长速率和菌落形态;PDA培养基上测定菌丝形态和菌丝融合率;CMC培养液中测定分生孢子的产量及形态;皮氏培养基上测定孢子融合芽管调控的融合率。将假禾谷镰孢的菌丝块接种小麦胚芽鞘和大麦叶片测定病原菌的致病力,采用盆栽试验测定假禾谷镰孢引起的小麦茎基腐病。在PDA培养基中分别加入刚果红、SDS和过氧化氢测定假禾谷镰孢对细胞壁、细胞膜和氧化胁迫的耐受性。【结果】细胞自噬相关蛋白Atg3在真菌中非常保守,且与生物进化的方向一致,假禾谷镰孢FpAtg3与禾谷镰孢和尖镰孢的Atg3同源性最高。获得了FpAtg3基因缺失突变体和回补菌株,表型测定结果显示,与假禾谷镰孢野生型和回补菌株相比,ΔFpAtg3在营养培养基上的菌丝生长明显减慢,气生菌丝减少,菌丝呈波纹状卷曲,分生孢子产量减少,孢子变短,分生孢子分隔减少;野生型和回补菌株菌丝融合发生非常普遍,在相同条件下ΔFpAtg3的菌丝融合率和孢子融合芽管调控的融合率均明显降低;ΔFpAtg3侵染大麦叶片和小麦胚芽鞘造成的病斑较野生型和回补菌株侵染的病斑明显减小,盆栽试验进一步验证ΔFpAtg3的致病力降低;与野生型和回补菌株相比,ΔFpAtg3在刚果红、SDS和过氧化氢胁迫中的耐受性降低。【结论】自噬相关基因FpAtg3参与假禾谷镰孢的菌丝生长、分生孢子产生、菌丝融合、致病力以及对非生物胁迫的耐受性.

苯醚甲环唑拌种对小麦根际微生物群落的影响

小麦茎基腐病是我国北方小麦主产区的重大病害,对小麦安全生产造成严重威胁。化学农药的使用是最直接有效的防治方法,在植物病害防治中发挥重要作用。苯醚甲环唑是一种具有较高安全性的三唑类杀菌剂。本课题前期明确了苯醚甲环唑拌种对小麦茎基腐病有一定的防治效果,且促生增产,但其对小麦根际微生物的影响尚不清楚。本文研究了苯醚甲环唑拌种对茎基腐病田中小麦根际土壤微生物的影响,结果表明,苯醚甲环唑拌种处理对小麦分蘖期,拔节期和灌浆期根际微生物的alpha和beta多样性均无显著影响,但使分蘖期镰孢属的相对丰度显著降低。微生物共现网络分析表明,苯醚甲环唑拌种处理提高了细菌网络的复杂性,降低了真菌网络复杂性,使植株根际微生物网络更接近健康植株根际的特征。该研究从根际微生物的角度为苯醚甲环唑防治小麦茎基腐病的机制研究及对土壤微生物的安全性评价提供理论依据。

2022年河南省小麦茎基腐病和赤霉病病原种群分离鉴定

近年来,茎基腐病和赤霉病在中国黄淮麦区发生严重,对小麦产量及品质造成较大影响。各地报道小麦茎基腐病和赤霉病病原菌种类有所差异。为明确当前中国小麦主产区河南小麦茎基腐病和赤霉病病原菌种类变化情况,本研究对2022年采自河南省安阳、漯河、周口、南阳等8个不同生态区的小麦茎基腐病病株和赤霉病病穗进行了分离纯化,分别得到257和88株分离物。形态学及分子生物学鉴定结果表明,小麦茎基腐病样品分离物中,假禾谷镰孢菌(Fusarium pseudograminearum)231株,占比89.88%;禾谷镰孢菌(F.graminearum)23株,占比8.95%。赤霉病样品的分离物中,禾谷镰孢菌76株,占比86.36%;假禾谷镰孢菌10株,占比11.36%。2022年河南省所有采样地区的茎基腐病的优势病原菌均为假禾谷镰孢菌,赤霉病的优势病原菌仍为禾谷镰孢菌,但赤霉病样品分离物中假禾谷镰孢菌的占比有所增长,特别是在安阳、平顶山和漯河市的赤霉病样品中假禾谷镰孢菌的分离频率达到了10%以上。

北京地区小麦赤霉病和茎基腐病的病原群体组成

随着北京市小麦种植面积的逐步恢复,小麦赤霉病和茎基腐病的发生范围也逐渐扩大。为明确北京地区小麦赤霉病及茎基腐病的病原群体组成,于2023年从北京市6个区14个采样点采集小麦赤霉病和茎基腐病样品,采用组织分离法得到290株小麦赤霉病菌株及163株小麦茎基腐病菌株。采用翻译延伸因子TEF1-α基因进行分子鉴定,明确了北京地区不同区县小麦赤霉病菌和茎基腐病菌的群体组成。北京地区小麦赤霉病的病原主要是禾谷镰孢Fusarium graminearum和假禾谷镰孢F.pseudograminearum,其中禾谷镰孢占群体总数的92.41%,是整个北京地区的优势致病菌,也是海淀、平谷、顺义、密云和延庆地区的优势致病菌,假禾谷镰孢是怀柔地区的优势致病菌。北京地区小麦茎基腐病的病原主要是假禾谷镰孢(45.40%)和禾谷镰孢(37.42%),还分离出层出镰孢F.proliferatum(1.23%)、中华镰孢F.sinense(7.36%)、锐顶镰孢F.acuminatum(4.29%)、三线镰孢F.tricinctum(3.07%)和木贼镰孢F.equiseti(1.23%)。海淀和密云地区的小麦茎基腐病优势致病菌是假禾谷镰孢,平谷、顺义和延庆地区的优势致病菌是禾谷镰孢。该研究结果为小麦赤霉病和茎基腐病的预测预报和精准防治提供依据。

拮抗假禾谷镰孢菌的LZ-7菌株筛选、 鉴定及其生防潜能

【目的】从土壤中分离和筛选能够拮抗小麦茎基腐病病原菌假禾谷镰孢菌的细菌菌株,鉴定其种类,分析其生防潜能。【方法】将采自西藏林芝自然生境树木根围的土壤,用无菌水溶解后取上清液,采用稀释涂布平板法分离细菌;细菌纯化后在PDA平板上与假禾谷镰孢菌进行对峙培养,筛选拮抗假禾谷镰孢菌的菌株;根据菌株的形态特征、生理生化特性及16S rDNA的系统进化分析鉴定生防菌株的种类;利用土壤接种方法,测定生防菌株发酵液对小麦苗期小麦茎基腐病的生防潜能;采用平板对峙法测定生防菌株对其他病原真菌的抑菌谱。【结果】分离筛选获得一株拮抗假禾谷镰孢菌菌丝生长的细菌LZ-7,该菌株对假禾谷镰孢菌菌落的抑制率为52.3%。LZ-7菌株具有产淀粉酶、纤维素酶、脲酶和明胶酶的能力,能利用多种碳源,其16S rDNA序列与娄彻氏链霉菌聚在同一分支,被鉴定为娄彻氏链霉菌。LZ-7菌株的发酵液处理小麦种子后,苗期茎基腐病的病情指数降低了58.4%。此外,菌株LZ-7对禾谷镰孢菌和麦根腐平脐蠕孢等植物病原真菌也具有明显的拮抗活性。【结论】在青藏高原土壤中筛选到一株娄彻氏链霉菌LZ-7,拮抗假禾谷镰孢菌的生长,对小麦茎基腐病具有良好防治潜能,具备作为小麦茎基腐病生防资源开发利用的潜力。

番茄颈腐根腐病病原菌鉴定及抗性品种筛选

番茄颈腐根腐病是设施番茄冬春生产中最严重的病害之一,严重威胁我国设施番茄的安全生产。近年来番茄颈腐根腐病在我国番茄主产区发生日益严重,培育抗病品种是防治该病最经济有效的方法。本试验采集典型症状的发病植株进行病原菌分离纯化,综合运用形态学观察、分子生物学鉴定和致病性测定方法,确定病原菌为尖孢镰刀菌番茄颈腐根腐病专化型(Fusarium oxysporum f.sp.radicis-lycopersici,Forl)。之后利用分离的病原菌通过苗期人工接种鉴定结合抗性基因分子标记方法,对32个番茄商品种进行抗颈腐根腐病鉴定分析,结果显示有18个表现抗病,与分子标记Frl-ZL的鉴定结果一致,可用于番茄抗颈腐根腐病育种或生产。

黄淮麦区小麦品种对两种镰孢菌(Fusarium)的抗性鉴定

为掌握我国黄淮麦区主推或新近选育小麦品种对假禾谷镰孢菌(Fusarium pseudograminearum)和禾谷镰孢菌(F.graminearum)的抗性水平,采用室内苗期接种法和田间穗期单花滴注接种法对黄淮麦区主推或新近选育的135份小麦品种进行了抗性评价。结果表明,供试小麦品种中,对假禾谷镰孢菌和禾谷镰孢菌没有免疫(I)和高抗(HR)的品种。在室内苗期接种条件下,对假禾谷镰孢菌仅有3个品种表现中抗(MR),占供试品种的2.59%,表现感病(S)的品种有10个,占8.62%,103个小麦品种表现高感(HS),占88.79%;对禾谷镰孢菌表现中抗(MR)的小麦品种有23个,占供试的19.83%,表现感病(S)的品种有50个,占43.10%,43个品种表现高感(HS),占37.07%。在田间穗期单花滴注接种条件下,对假禾谷镰孢菌表现抗病(R)的品种有6个,占5.17%,表现中抗(MR)的品种有10个,占8.62%,表现中感(MS)的品种有62个,占53.45%,表现感病(S)的有34个,表现高感(HS)的有4个品种;对禾谷镰孢菌仅苏麦3号1个品种表现抗病(R,0.86%),囤麦127和丰德存1号表现中抗(MR,1.72%),37个品种表现中感(MS),49个品种表现感病(S),26个品种表现高感(HS)。供试小麦品种对两种镰孢菌不同时期的抗性表现存在明显差异,室内苗期接种条件下,抗假禾谷镰孢菌的品种少;而田间穗期单花滴注接种条件下,抗禾谷镰孢菌的品种少。

粉唑醇对假禾谷镰刀菌的抑菌活性及田间防效

【目的】探明粉唑醇对小麦茎基腐病的防控效果,为粉唑醇在小麦安全生产上的应用提供依据。【方法】通过菌丝生长速率法测定1%粉唑醇颗粒剂对小麦茎基腐病致病菌假禾谷镰刀菌18-HX-16、19-HA-4、20-XX-13等10个菌株的室内毒力,每个菌株设置3次重复,培养48 h后计算粉唑醇对不同菌株的毒力回归方程及EC_(50)值,分析粉唑醇对假禾谷镰刀菌的抑菌活性;采用田间随机小区试验法,1%粉唑醇颗粒剂设置3个施药量(20 g/667m^(2)、30 g/667m^(2)、50 g/667m^(2))拌种进行田间防效试验。【结果】粉唑醇对供试假禾谷镰刀菌的EC_(50)在0.050~0.894μg/mL,平均为0.400μg/mL;1%粉唑醇颗粒剂对小麦茎基腐病的田间防效在49.98%~74.59%,其中,1%粉唑醇颗粒剂施药量为50 g/667m2时,小麦茎基腐病的发病率低至16.00%、病情指数低至5.87,防效高达74.59%,显著优于对照药剂(1%噁霉灵颗粒剂)的防治效果。【结论】粉唑醇对假禾谷镰刀菌具有较高的抑菌活性,对田间小麦茎基腐病有较好的防控效果,1%粉唑醇颗粒剂以50 g/667m2用量与复合肥混匀施用,对小麦茎基腐病的防效最好。

小麦种质资源茎基腐病抗性鉴定及定位分析

采用小米培养基接种法对163份当前推广的小麦种质资源进行室内和田间茎基腐病抗性鉴定。结果表明,没有鉴定出高抗和免疫的小麦材料,但是不同材料的抗性能被明显区分,群体抗性整体上呈现正态分布趋势,室内鉴定病情指数分布在13.28~83.33之间,田间鉴定病情指数分布在10.27~73.89之间。室内和田间鉴定结果较稳定,两环境病情指数的相关系数为0.79,说明室内鉴定结果可较好反映田间抗性情况。全基因组关联分析(GWAS,genome-wide association study)显示,显著SNP广泛分布于小麦各条染色体上,其中2A上最多,集中在725~763 Mb区段内。进一步集群分离分析法(BSA,bulked segregant analysis)结果显示,显著SNP集中在2A上的730~750 Mb区段内。综合来看,小麦2A染色体上730~750 Mb区段内可能存在显著调控小麦茎基腐病的抗性基因。本研究能够为小麦茎基腐病抗性材料筛选及抗病位点挖掘提供重要的参考意义。

A cell wall invertase modulates resistance to fusarium crown rot and sharp eyespot in common wheat

Fusarium crown rot(FCR) and sharp eyespot(SE)are serious soil-borne diseases in wheat and its relatives that have been reported to cause wheat yield losses in many areas. In this study, the expression of a cell wall invertase gene, TaCWI-B1,was identified to be associated with FCR resistance through a combination of bulk segregant RNA sequencing and genome resequencing in a recombinant inbred line population. Two biparental populations were developed to further verify TaCWI-B1 association with FCR resistance.Overexpression lines and ethyl methanesulfonate(EMS) mutants revealed TaCWI-B1 positively regulating FCR resistance. Determination of cell wall thickness and components showed that the TaCWI-B1-overexpression lines exhibited considerably increased thickness and pectin and cellulose contents. Furthermore, we found that TaCWI-B1 directly interacted with an alphagalactosidase(TaGAL). EMS mutants showed that TaGAL negatively modulated FCR resistance. The expression of TaGAL is negatively correlated with TaCWI-B1 levels, thus may reduce mannan degradation in the cell wall, consequently leading to thickening of the cell wall. Additionally, TaCWI-B1-overexpression lines and TaGAL mutants showed higher resistance to SE;however, TaCWI-B1 mutants were more susceptible to SE than controls.This study provides insights into a FCR and SE resistance gene to combat soil-borne diseases in common wheat.

一种简便分离假禾谷镰刀菌的选择性培养基

以马铃薯蔗糖琼脂培养基为基础培养基,添加适宜剂量的硫酸链霉素、乙膦铝、代森锰锌、多菌灵,通过试验,筛选出了一种能在非无菌条件下分离假禾谷镰刀菌(Fusarium pseudograminearum)的选择性培养基。结果表明:4种物质的质量浓度分别为75~100μg/mL、150~250μg/mL、6.25~25μg/mL和0.0625~0.25μg/mL时,可有效抑制从小麦茎基腐病发病茎秆上分离假禾谷镰刀菌时最常出现的3类污染菌即链格孢(Alternaria sp.)、青霉(Penicillium sp.)和曲霉(Aspergillus sp.)的生长,而对假禾谷镰刀菌影响较小。4种物质的最适质量浓度分别为75μg/mL、200μg/mL、6.25μg/mL和0.25μg/mL,在该配比下,对3种污染菌生长的抑制率均在90%以上,而对假禾谷镰刀菌的抑制率不到30%,且菌落典型。