A novel pathogen Fusarium cuneirostrum causing common bean(Phaseolus vulgaris)root rot in China

Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean in China,but the species of Fusarium spp.have remained unclear.Thus,this study was performed to identify the pathogen causing common bean root rot in Liangcheng County,Inner Mongolia,China.Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification.The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean,while 11 other isolates were not pathogenic.The eight pathogenic isolates,FCL1–FCL8,were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α,ITS,28S,and IGS regions.Host range test showed that the representative F.cuneirostrum isolate FCL3 was also pathogenic to mung bean,while not pathogenic to adzuki bean,chickpea,cowpea,faba bean,pea,and soybean.Moreover,50 common bean and 50 mung bean cultivars were screened for resistance to FRR,and seven highly resistant or resistant cultivars of common bean were identified,while no resistant cultivars of mung bean were screened.This study revealed that F.cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well.To our knowledge,this is the first report of F.cuneirostrum causing FRR of common bean in China.

Effects of Torreya grandis Root Rot on Seedling Growth and Screening of Its Chemical Control Agents

[Objectives]This study was conducted to prevent the occurrence of root rot disease in Torreya grandis and improve the yield and quality of T.grandis.[Methods]One-year-old and two-year-old seedlings of Torreya grandis‘Xifei’and‘Cufei’were inoculated with the root rot pathogen Fusarium fujikuroi,and the changes in photosynthesis,chlorophyll content,malondialdehyde,and defense enzyme system(superoxide dismutase,peroxidase,and catalase)activity in leaves of T.grandis seedlings were investigated using water as a control.Meanwhile,the control effects of 80%carbendazim wettable powder,64%metalaxyl·mancozeb wettable powder,430 g/L tebuconazole suspension and 30%difenoconazole·cyproconazole EC on root rot in T.grandis were investigated.[Results]After inoculation with the pathogen F.fujikuroi,the net photosynthetic rates and transpiration rates in leaves of T.grandis‘Xifei’and‘Cufei’decreased,and the contents of chlorophyll decreased,while the contents of malondialdehyde increased,and the contents of superoxide dismutase and catalase increased with time.However,peroxidase showed a high activity in T.grandis‘Cufei’only,but a trend of"increasing-decreasing-increasing"in T.grandis‘Xifei’.Among the four chemical control agents,64%metalaxyl·mancozeb wettable powder had the best control effect on root rot of T.grandis caused by the pathogenic fungus F.fujikuroi.[Conclusions]The net photosynthetic rate,transpiration rate,chlorophyll content,malondialdehyde content,superoxide dismutase activity and catalase activity could all be used as screening indicators for T.grandis varieties resistant to root rot.Meanwhile,64%metalaxyl·mancozeb wettable powder could be used as a control agent for root rot on T.grandis.

Formulation of Biofungicides from Cymbopogon citratus and Tithonia diversifolia: Evaluating Its Antimicrobial Activities against Pythium myriotylum, the Causal Agent of Root Rot of Xanthosoma sagittifolium (L.) Schott

Three fungicide formulations, namely M1, M2 and M3, were prepared from sodium bicarbonate, citronella essential oil and sunflower slurry. The stability of M1, M2 and M3 formulations was determined based on pH, temperature, order of incorporation of the inputs and storage time. The most stable formulations were used for antagonistic tests on Pythium myriotylum. The Minimum Inhibitory Concentration (MIC) was used for the greenhouse tests and the mode of action was determined in vitro. The study showed that the order of incorporation of the inputs “Essential Oil-Tween 80-Bicarbonate-Slurry” (EO-T80-B-S) promotes stability. M1 and M2 are stable at 4°C, 25°C, 37°C and 40°C temperatures and have a pH of 7 and 8 respectively. The Minimum Inhibitory Concentration of M1 and M2 is 1% on P. myriotylum. M1 and M2 act on Pythium by membrane lysis, inhibiting proton pumps and inhibiting protein synthesis. The formulations M1 and M2 reduce the incidence of root rot disease in cocoyam plants growth in the greenhouse. M1 and M2 are potential candidates for improvement of cocoyam seedlings production in Cameroon.

Resistance Evaluation of Soybean Germplasm from Huanghuai Region to Phytophthora Root Rot

The aim of the study was to establish a set of differential strains and to identify soybean resistant genes to Phytophthora root rot and then to apply those strains for analysis of the resistant genes Rps1a,Rps1c,and Rps1k that soybean cultivars or lines may carry.Virulence formula of 125 Phytophthora sojae isolates were determined using the hypocotyls inoculation technique,the strains,which includ 6 isolates with different virulence formulas,were applied to identify the resistance of 55 soybean cultivars or lines and resistant genes were analyzed using the gene postulating procedure.Eighteen reaction types occurred in 55 cultivars or lines and results of gene postulation indicated that 2 cultivars or lines probably carried gene Rps1c and no cultivar may carry genes Rps1a or Rps1k.A few of soybean cultivars or lines from Huanghuai Region carry Rps genes Rps1a,Rps1c and Rps1k and tend to infect by P.sojae,so resistant cultivars or lines need to be bred and popularized actively.

Impact of long-term chemical fertilizer and organic amendment to Fusarium root rot of soybean

Soil suppressiveness to Fusarium root rot of soybean had been observed in a black soil field after a long-term fertilization with nitrogen(N)and phosphorus(P)fertilizer combined with pig manure as organic amendment(NPM),rather than that with only nitrogen and phosphorus fertilizer(NP)or no fertilizer(NF).To determine the microbial role on this suppressiveness,fungal and bacterial community characteristics in NPM,NP and NF treatments were investigated by q PCR and DGGE.Compared with the similar bacterial community characteristics among 3 treatments,fungal community,especially Fusarium population size and community composition in NPM treatment were different with those of NP and NF groups.Based on the isolation and pathogenicity test,pathogenic F.oxysporum,F.graminearum,F.verticillioide and F.lateritium absolutely dominated Fusarium community in NF and NP groups.Nonpathogenic F.avenaceum,F.equiseti,F.culmorum,F.redolens,F.solani and F.tricinctum dominated Fusarium community in NPM group.Isolation rate of pathogenic Fusarium in NPM reduced from 100%to 38%in NF.These results suggested that the dominance of soil non-pathogenic Fusarium population induced by organic amendment might play an important role on suppressing Fusarium root rot in the tested field.

Isolation and Identification of Root Rot Fungus of Astragalus membranaceus

The perennial root of Astragalus membranaceus is used as a medicine, while root rot is a main factor causing reduction of quality and commodity value of A. membranaceus . The screening and research of the pathogenic species and their characteristics could provide theoretical and practical basis for the control of this disease. A pathogenic strain was isolated and purified from the root part of four-year-old A. membranaceus , and identified by morphological and molecular biological methods as Fusarium oxysporum . This study will provide a theoretical basis for the research of the biological characteristics and control of F. oxysporum .

Occurrence Regularity and Prevention and Control Technology of Kiwifruit Root Rot

Kiwifruit root rot is an important root disease of kiwifruit, which has occurred increasingly in recent years. The disease leads to the death of whole kiwifruit plant under severe condition, and has become an important disease restricting kiwi fruit industry development. The characteris-tics, occurrence, etiology and symptoms of kiwifruit root rot were introduced in the paper, and the prevention and control technology against the dis-ease were put forward from the aspects of agriculture, biology and chemistry.

First Report of Fusarium striatum Causing Root Rot Disease of Panax notoginseng in Yunnan,China

Panax notoginseng is a traditional Chinese medicinal plant.Root rot of P.notoginseng is one of the most serious diseases affecting P.notoginseng growth and causes wilted leaves,fewer lateral roots and rotten roots.Root rot is a soil-borne disease,and mainly occurs from June to August in Yunnan Province when the temperatures are high and the air is humid.In this study,the endophytic fungal genus Fusarium isolate E-2018.1.22-#3.2 was obtained from a P.notoginseng embryo.Fusarium isolate E-2018.1.22-#3.2 was identified as Fusarium striatum based on morphological characteristics and molecular analysis.The fungus was found to have conidiophores and macroconidia,and its ITS,LSU and TEF-1αgenes shared 100%,99.2%and 99%identities with the homologous genes of Fusarium striatum,respectively.Isolate F.striatum E-2018.1.22-#3.2 can cause root rot symptoms,including black,soft roots,fewer lateral roots and leaf wilt,in 93%of the experimental P.notoginseng plants,and could be re-isolated,fulfilling Koch’s postulates.When the P.notoginseng plants were treated with the fungicide pyraclostrobin,isolate F.striatum E-2018.1.22-#3.2 was unable to cause root rot.We have therefore demonstrated that F.striatum E-2018.1.22-#3.2 is able to cause root rot disease in P.notoginseng.This is the first report of root rot disease caused by F.striatum on P.notoginseng in China.

QUANTITATIVE ANALYSIS OF RELATIONSHIP BETWEEN ARMILLARIA ROOT ROT AND SITE FACTORS IN PINUS RADIATA PLANTATIONS

Incidence of Armillaria infection was quantified based on site factors in New Zealand Pinus radiata plantations.A linear multiple regression model was derived to predict infection levels of Armillaria root rot.Factors positivily associated with the infection were:previous vegetation（native bush,pine）;soil type（pumice）;landform （valley,gully,flat）and the interaction between them.This model could assist in management planning with regard to the predisposition of particular stand to Armillaria infection.Keywods:Armillaria root rot,Disease incidence,Site factors,Quantification,Pinus radiata.

Biological Characteristics of Root Rot Pathogen on Sambucus chinensis

Effects of different media,pH values,temperatures,carbon and nitrogen sources on mycelial growth and sporulation of root rot pathogen on Sambucus chinensis was determined in the paper.The results showed that root rot pathogen on S.chinensis was identified as Fusariumsp.The mycelial growth and sporulation of Fusariumsp.in PSA medium was the best;the optimal temperature for mycelial growth and sporulation was from 25℃ to 30℃ and the optimal temperature was 28℃;the suitable pH values for mycelial growth and sporulation was from 5 to 7,and the optimum pH value was 6;the absence or presence of carbon sources had significant effect on growth of Fusariumsp.;sucrose was the best carbon source utilized in mycelial growth,while lactose was the worst; KNO3 was the best nitrogen source utilized in mycelial growth,while（NH4） 2 SO4 was the worst one.

Research Advances of Root Rot in Medicago sativa L.

As the most famous perennial leguminous forage in the world, Medicago sativa L. ranks the first in both yield and nutritional value, and can be used for many years once planted in field production. However, root rot has become a very important reason for yield decrease and plant de-cline of alfalfa due to long service life. According to the research progress at home and abroad, the main pathogen distribution, harms and control methods of root rot in M. sativa at home and abroad were systematically expounded, in order to provide a theoretical basis for further research of the disease.

Polygenic Heritability of Rose Root Rot Disease Resistance in Offspring of Rosa multiflora

Rose root rot disease caused by Pythium helicoides Drechsler has brought heavy damage to cut rose production in Japan,and it has became apparent that Rosa multiflora showed resistance to this disease.Roses have been bred by interspecies crossing with Rosa species including of R.multiflora,and many progenies of R.multiflora have been bred as determined cluster-flowered roses.However,the genetic architecture of this resistance remains.So,in this study,four kinds of R.multiflora and 21 rose cultivars that have been clarified in the cross-fertilization genealogy with R.multiflora were used as plant materials,and the inheritability of resistance to root rot disease was investigated.Four kinds of R.multiflora had all high resistance,and the resistance to root rot disease in R.multiflora was inherent characteristic of species.Five varieties not less than 50% in relatedness with R.multiflora were shown as varied ‘resistant’ and ‘moderately resistant’.Therefore,the inherent resistant characteristic in R.multiflora was not controlled by single major gene,and the resistibility in R.multiflora was not cytoplasmic but nuclear heredity.Although there was significant negative relation between relative root rot severity and relatedness with R.multiflora,the variance of relative root rot severity had tendency to expand as relatedness with R.multiflora reduced.This result,therefore,indicated that the contingency of resistance expression increased as the relatedness with R.multiflora was reduced.The varieties having low degree of relatedness with R.multiflora had similar relative root rot severity with R.multiflora.These results indicated that we would be able to select resistant roses from progenies crossed with R.multiflora.

Unravelling Effects of Temperature and Soil Moisture Stress Response on Development of Dry Root Rot [<i>Rhizoctonia bataticola</i>(Taub.)] Butler in Chickpea

Erratic rainfalls and rise in temperature have become more frequent under the changing scenario of climate particularly in semiarid tropics. As a consequence of it, a drastic shift of chickpea diseases have been recorded throughout the major chickpea growing regions in India and elsewhere. Dry root rot (DRR) caused by Rhizoctonia bataticola (Taub.) Butler [Pycnidial stage: Macrophomina phaseolina (Tassi) Goid] was found as a potentially emerging constraint to chickpea production than wilt (Fusarium oxysporum f. sp. ciceris). Increasing incidence of DRR indicate strong influence of climate change variables such as temperature and moisture on the development of disease. The present study therefore was conducted to quantify the role of temperature and soil moisture associated with infection, colonization and development of DRR under controlled environment. The DRR incidence was significantly affected by high temperature and soil moisture deficit. Out of five temperature regimes (15?C, 20?C, 25?C, 30?C and 35?C) and four moisture levels (40%, 60%, 80% and 100%), a combination of high temperature (35?C) and soil moisture content (60%) predisposes chickpea to DRR. The study clearly demonstrates that high temperature coupled with soil moisture deficit is the climate change variables predisposing chickpea to R. bataticola infection, colonization and development.

Evaluation of phytophthora root rot-resistant <i>Capsicum annuum</i>accessions for resistance to phytophthora foliar blight and phytophthora stem blight

A mixture of six Georgia isolates of Phytophthora capsici (Leon.), the causal agent of phytophthora blight, were used for greenhouse mass screening of over 700 accessions of Capsicum annuum for both stem blight and foliar blight. From this screening, it was determined that resistance to both forms of the disease were relatively common in the germplasm, but resistance to one form of the disease was not strongly correlated to resistance to the other form. Ten accessions previously shown to possess root rot resistance were tested for resistance to stem rot and leaf blight, and were found to also be highly resistant to these forms of the disease. It appears that single accessions have resistance to foliar, stem and root rot caused by P. capsici, which may simplify breeding for resistance to all three forms of the disease.

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.

Assessing cotton defoliation, regrowth control and root rot infection using remote sensing technology

Cotton defoliation and post-harvest destruction are important cultural practices for cotton production.Cotton root rot is a serious and destructive disease that affects cotton yield and lint quality.This paper presents an overview and summary of the methodologies and results on the use of remote sensing technology for evaluating cotton defoliation and regrowth control methods and for assessing cotton root rot infection based on published studies.Ground reflectance spectra and airborne multispectral and hyperspectral imagery were used in these studies.Ground reflectance spectra effectively separated different levels of defoliation and airborne multispectral imagery permitted both visual and quantitative differentiations among defoliation treatments.Both ground reflectance and airborne imagery were able to differentiate cotton regrowth among different herbicide treatments for cotton stalk destruction.Airborne multispectral and hyperspectral imagery accurately identified root rot-infected areas within cotton fields.Results from these studies indicate that remote sensing can be a useful tool for evaluating the effectiveness of cotton defoliation and regrowth control strategies and for detecting and mapping root rot damage in cotton fields.Compared with traditional visual observations and ground measurements,remote sensing techniques have the potential for effective and accurate assessments of various cotton production operations and pest conditions.

Anti‑inflammatory and Cytotoxic Triterpenes from the Rot Roots of Panax notoginseng

Four new protopanaxatriol-type triterpenes(1-2)and glucosides(3-4),were isolated from the rot roots of Panax notoginseng(Burk.)Chen,along with four known ones(5-8).Their structures were elucidated on the basis of extensive spectroscopic analysis(HRESIMS,NMR,UV,IR,and OR)and acidic hydrolysis.The possible transformation pathway of these compounds were also speculated from ginsenoside Rg_(1).Compound 1,with a uniqueα,β-unsaturated ketene in its side chain,showed significant inhibitory effects against NO production on Murine macrophage cells(IC_(50)=4.12±0.20μM)and comparable cytotoxicities against five human cancer cell lines(myeloid leukemia HL-60,lung cancer A-549 cells,hepatocellular carcinoma SMMC7721,breast cancer MCF-7,and colon cancer SW480)to positive control,cisplatin(DDP).

Root and Foot Rot Diseases of Winter Wheat Grown in Conventional and Organic Systems

The object of the study was fungous diseases occurring on roots, leave sheaths and stem base of winter wheat in the two opposing cropping systems (organic and conventional). The observations were made in vegetation periods (2007-2009) in the fields of winter wheat in northern Poland. Every year on each plot of compared farming systems root rot occurred (Fusarium spp., Gaeumannomyces graminis and other fungi). For the period of 3 years the degree of disease injury on the roots of winter wheat grown in the conventional system in the vegetation period increased, while in the organic one remained on pretty the same level. On average a lot more affected roots, especially in the flowering stage, occurred on the winter wheat grown in the conventional system. Fusarium foot rot (Fusarium spp.) developed on the wheat during the entire vegetation period. It was the most dangerous root and foot rot disease (the highest indexes of injury). The mean degree of disease injury on leave sheath was on pretty the same level in the two farming systems, although in investigated vegetation periods differed a lot, whereas at the bases of stems the pathogen was on the higher level on the wheat in the conventional system. Also eyespot (Tapesia yallude) developed in the entire vegetation period of the winter wheat, but its intensity was much lower than in case of fusarium foot rot. Leave sheaths of the wheat grown in the conventional system were slightly stronger affected than those grown in the organic system. In the flowering stage the intensity of the disease in both farming systems became equal, while in the wax maturity it was considerably higher in the conventional system. Sharp eyespot (Rhizoctonia spp.) appeared relatively late and occurred only in two years of investigation. The intensiveness of the disease was definitely higher on the organic plots. Among the affected roots, taken in the stem elongation stage, from the organic system 28 cultures of fungi were isolated, and from the conventional one 24 colonies. Cereals pathogenic fungi amounted 35.8% of isolates obtained from the organic system and as many as 66.7% from the conventional system. Among the affected roots, taken in the flowering stage, from the organic system 68 cultures of fungi were isolated in all, and from the conventional one 25 colonies. Cereals pathogenic fungi amounted 38.2% of isolates obtained from the organic system and 56.0% from the conventional system. Among the affected stem bases, taken in the wax maturity stage, from the organic system 56 cultures of fungi were isolated in all, and from the conventional one 52 colonies. Cereals pathogenic fungi amounted 48.4% of isolates obtained from the organic system and 53.6% from the conventional system. In the case of all root and foot rot diseases of wheat grown in the organic system, an advantageous influence of greater biodiversity and number of various fungi species living in root proximity was noticed as opposed to the conventional system.