Phoma medicaginis Isolate Differences Determine Disease Severity and Phytoestrogen Production in Annual Medicago spp.

Plant Disease ◽  
2021 ◽  
Author(s):  
Mahtab Omidvari ◽  
Gavin Flematti ◽  
Ming Pei You ◽  
Payman Payman Abbaszadeh-Dahaji ◽  
Martin John BARBETTI
Keyword(s):  
Disease Severity ◽  
Disease Incidence ◽  
Severe Disease ◽  
Fold Increase ◽  
Leaf Spot Disease ◽  
Leaf Disease ◽  
Phoma Medicaginis ◽  
Annual Medicago ◽  
Relationship Of ◽  
Medicago Species

Phoma black stem and leaf spot disease of annual Medicago spp., caused by Phoma medicaginis, not only can devastate forage and seed yield, but also reduces herbage quality by inducing production of phytoestrogens, particularly coumestrol and 4'-O-methylcoumestrol, that can reduce ovulation rates of animals grazing infected forage. We determined the consequent phytoestrogen levels on three different annual Medicago species/cultivars (M. truncatula cv. Cyprus, M. polymorpha var. brevispina cv. Serena and M. murex cv. Zodiac), following inoculation with 35 isolates of P. medicaginis. Across the isolate x cultivar combinations, leaf disease incidence (%LDI), petiole disease incidence (%PDI), leaf disease severity (%LDS), petiole disease severity (%PDS), and leaf yellowing severity (%LYS) ranged up to 100, 89.4, 100, 58.1 and 61.2%, respectively. Cultivars Cyprus and Serena were most susceptible and cv. Zodiac the most resistant to P. medicaginis. Isolates WAC3653, WAC3658 and WAC4252 produced the most severe disease. Levels of phytoestrogens in stems ranged from 25 to 1995 mg/kg for coumestrol and from 0 to 418 mg/kg for 4'-O-methylcoumestrol. There was a significant positive relationship of disease incidence and severity parameters with both coumestrol and 4'-O-methylcoumestrol contents, as noted across individual cultivars, and as across the three cultivars overall where r=0.39 and 0.37 for coumestrol and 4'-O-methylcoumestrol, respectively (P<0.05). Although, cv. Serena was most susceptible to P. medicaginis and produced the highest levels of phytoestrogens in the presence of P. medicaginis, cv. Zodiac contained the highest levels of phytoestrogens in comparison with other cultivars in the absence of P. medicaginis. There was a 15-fold increase in coumestrol in cv. Serena but only a 7-fold increase in cv. Zodiac from infection of P. medicaginis. The study highlights that the intrinsic ability of a particular cultivar to produce phytoestrogens in the absence of the pathogen, and its comparative ability to produce phytoestrogens in the presence of the P. medicaginis, are both important and highly relevant to developing new annual Medicago spp. cultivars that offer improved disease resistance and better animal reproductive outcomes.

Resistance in annual Medicago species to Phoma medicaginis and Leptosphaerulina trifolii under field conditions

1995 ◽  
Vol 35 (2) ◽  
pp. 209 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Disease Resistance ◽  
Field Conditions ◽  
Breeding Lines ◽  
Disease Progress Curve ◽  
Leaf Disease ◽  
Progress Curve ◽  
Phoma Medicaginis ◽  
Annual Medicago ◽  
Medicago Species ◽  
New Cultivars

Advanced breeding lines and potential new cultivars of annual Medicago species were screened for resistance to phoma leaf and stem disease (caused by Phoma medicaginis) and pepper spot (caused by Leptosphaerulina trifolii) in the field, and their performances were compared with appropriate control cultivars. Medicago murex had the best overall disease resistance of the Medicago species tested. There were large differences between varieties in the incidence of both diseases. Based on end-of-season scores, the most resistant to phoma leaf disease included M. murex cv. Zodiac and SAR 3490, M. tornata SA10012, and M. truncatula cv. Parabinga, with scores 52.8 on a 0-10 scale (0, nil disease; 10, >90% leaves affected). On the basis of area under disease progress curve (AUDPC), the most resistant to phoma leaf disease, with AUDPC values of <157, included all M. murex varieties except 87FB2.30, and M. truncatula cv. Caliph. Based on end-of-season scores, the most resistant to phoma stem disease, all with scores c4, included M. murex cv. Zodiac, SAR 3490, and 87F01.48; M. sphaerocarpos cv. Orion (SEP 29.1), SEP 29.2, and SEP 30.3; and M. tornata cv. Tornafield and SA10012. Resistance to phoma stem disease in these lines was confirmed by AUDPC values, especially for M. murex cv. Zodiac, SAR3490, and 87FO1.48, and for M. tornata SA10012, with values <154. Based on end-of-season scores, the most resistant to pepper spot leaf disease included M. polymorpha cvv. Serena and Circle Valley, with scores 52.8. On the basis of AUDPC, all M. murex varieties except SAR3490 and 87FO1.5 could be included among those most resistant to pepper spot leaf disease, with AUDPC values <275. Coumestrol levels in stems ranged from 117 to 1420 mg/kg DW, with lowest levels (5330 mg/kg) in M. murex cv. Zodiac, 87FO 1.48, and GRC 87; M. sphaerocarpos cv. Orion (SEP 29.1), SEP 29.2, and SEP 26.2.1; M. tornata cv. Tornafield; and M. truncatula Z601. There was positive correlation between the severity of phoma disease on stems and end-of-season (September-November) coumestrol concentrations.

An improved method for artificial hybridization in annual Medicago species

1994 ◽  
Vol 45 (7) ◽  
pp. 1329 ◽  
Author(s):  
W Pathipanawat ◽  
RAC Jones ◽  
K Sivasithamparam
Keyword(s):  
Success Rate ◽  
Fold Increase ◽  
Modified Technique ◽  
Established Method ◽  
Artificial Hybridization ◽  
Annual Medicago ◽  
Improved Technique ◽  
Medicago Species ◽  
First Time ◽  
Selection Of

An improved technique for successful artificial hybridization in annual medic (Medicago spp.) is described. Using a previously reported method, only four out of seven species were successfully crossed, with the percentage of success ranging from 3 to 22%. Initial modifications to this technique gave a 7-8 fold increase in the successful crossing rate in M. murex and M. polymorpha medic, from 9 to 64% with M. murex and from 10 to 82% with M. polymorpha. Further modifications to the technique resulted in a success rate of 100% in both species. The numbers of seeds per pod obtained from crosses in both species were also increased by using the modified techniques compared to the established method. Selection of larger, more mature flowers, differences in flower cutting position, as well as post pollination position were the main modifications which accounted for the greatly improved success rate. The modified technique was subsequently applied successfully to obtain for the first time inter-specific crosses involving M. polymorphax M. murex, M. polymorphax M. sphaerocarpos, M.murexx M. sphaerocarpos, M. solerolii x M. littoralis/M.truncatula hybrid, M. solerolii x M, tornata, and M. littoralis/M.truncatula hybrid x M. sphaerocarpos.

Strategies for control of Phoma black stem in annual Medicago species

1989 ◽  
Vol 29 (5) ◽  
pp. 635 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Disease Severity ◽  
Medicago Truncatula ◽  
Field Trial ◽  
Subsequent Development ◽  
Field Site ◽  
Infected Seed ◽  
Annual Medicago ◽  
And Control ◽  
Medicago Species ◽  
Selection Of

Strategies for control of Phoma black stem disease in annual Medicago species through selection of cultivars with increased resistance to Phoma medicaginis, fungicidal spray applications to swards, and fungicidal control of seedborne infection, were investigated. Fiftyseven annual Medicago cultivars and lines were screened for resistance in the field in 1 m rows over 2 consecutive seasons. There were significant differences in resistance among species and also between lines and cultivars of any particular species. Three M. rugosa cultivars were very highly resistant and most cultivars and lines showed some resistance. In a field trial, the fungicides benomyl, carbendazim, flutriafol, propiconazole, thiabendazole and triadimefon were tested for their efficacy in controlling Phoma black stem disease. All fungicides reduced disease severity in the sward and, except for thiabendazole, the percentage burrs with Phoma lesions. The role and control of seed-borne P. medicaginis in causing Phoma black stem disease in Medicago truncatula and M. polymorpha var. brevispina at a field site was also investigated. Seed-borne P. medicaginis caused subsequent development of Phoma black stem disease in swards sown with infected seed. Disease appeared earlier, developed faster and became much more severe in M. truncatula cv. Cyprus than in M. polymorpha cv. Serena. Application of benomyl seed treatments (0.1 and 0.5% w/w) resulted in only a 4-5 week delay in the onset of Phoma black stem symptoms.

scholarly journals Effective Biomass Reduction of the Invasive Weed Species Banana Poka by Septoria Leaf Spot

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Eduardo E. Trujillo ◽  
Chris Kadooka ◽  
Victor Tanimoto ◽  
Steve Bergfeld ◽  
Glenn Shishido ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Severe Disease ◽  
Disease Spread ◽  
Leaf Spot Disease ◽  
Native Forest ◽  
Invasive Weed ◽  
Disease Epidemics ◽  
Biomass Reduction ◽  
Septoria Leaf Spot

Inoculations of Septoria passiflorae for biological control of banana poka (Passiflora tripartita var. tripartita) at different forest sites in Hawaii, Kauai, and Maui resulted in successful establishment of the Septoria leaf spot disease at all sites during 1996. Semi-annual monitoring of sites in 1997 revealed low disease incidence and no disease spread to adjacent non-inoculated plants. Site inspections in March 1998 revealed light disease epidemics causing visible defoliation at inoculated sites on Kauai and Maui. Banana poka biomass reduction at sites with light epidemics of the disease in Kauai and Maui were estimated to be less than 10% in 1998, whereas in 1999 biomass reduction ranged from 50 to 95%. Five of 11 inoculation sites in 1996 on the island of Hawaii showed no disease. These five sites on Kaloko had frequent acid rainfall averaging 3.2 pH, which inhibited spore germination and infection. Six sites, free of acid rain, three at Hilo Forest Reserve and three at Puuwaawaa Wildlife Sanctuary, had severe disease epidemics by 1998, and vine defoliation was >90%. Widespread epidemics of the disease occurred in 1999, resulting in estimated 80 to 95% biomass reductions in more than 2,000 hectares of native forest infested with banana poka.

scholarly journals Resistance in Annual Medicago spp. to Phoma medicaginis and Leptosphaerulina trifolii and Its Relationship to Induced Production of a Phytoestrogen

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 239-244 ◽  
Author(s):  
Martin J. Barbetti
Keyword(s):  
Field Tests ◽  
Dry Weight ◽  
Growing Season ◽  
Significant Negative Correlation ◽  
Leaf Disease ◽  
Herbage Quality ◽  
Phoma Medicaginis ◽  
Disease Resistances ◽  
Annual Medicago

Foliar and stem diseases of annual Medicago spp. caused by Phoma medicaginis and Leptosphaerulina trifolii can not only reduce yield, but also affect herbage quality by inducing the production of the phytoestrogen coumestrol. To determine differences in host reaction to these pathogens, 33 cultivars and lines in 1993 and 10 cultivars in 1995 were evaluated in inoculated field tests. In the 1993 test, a number of genotypes with high levels of resistance to leaf and stem disease caused by P. medicaginis and to leaf disease caused by L. trifolii were identified. Genotypes with very high levels of resistance to stem disease caused by P. medicaginis were M. sphaerocarpos GRC5659.4.1 and SAD10069, M. murex GRC87.1, GRC707, and GRC708, M. truncatula Z771, and M. solerolii DZA3180.1, all of which had stem disease scores of ≤1.0 (scale 0 to 10) by the end of the growing season. The levels of coumestrol produced ranged from 114 to 1,230 ppm dry weight in stems across the genotypes, and the score for stem disease caused by P. medicaginis in the corresponding cultivars ranged from ≤0.8 to 8.9, respectively. The 1995 test confirmed the relative responses of nine cultivars (Caliph, Circle Valley, Cyprus, Harbinger AR, Zodiac, Paraggio, Santiago, Serena, and Orion) of annual Medicago spp. to leaf and stem disease caused by P. medicaginis and to stem disease caused by L. trifolii. Those with the lowest levels of coumestrol in the stems were M. solerolii DZA3180.1, M. truncatula Paraggio, and M. sphaerocarpos SAD10069, all with levels ≤130 ppm. The highest level was found in M. polymorpha SA4178 (1,230 ppm). M. littoralis Harbinger AR, Z286, Z298, and Z912, M. murex 89F16.1.1, M. orbicularis SA8460, and M. polymorpha SA4188, all had coumestrol levels of >600 ppm. For stem disease caused by P. medicaginis in particular, there was significant correlation of the level of disease with the level of coumestrol in stems at the end of the growing season. In contrast, for L. trifolii, there was significant negative correlation (leaf disease) or only a weak positive correlation (stem disease) with coumestrol in stems at the end of the growing season. Incorporation of these identified disease resistances into commercial cultivars offers a promising avenue not only as a long-term strategy for management of foliar diseases in annual Medicago spp., but also as a means of reducing phytoestrogen levels in commercial annual Medicago spp. pastures in order to minimize the adverse effects of phytoestrogens on fertility levels in sheep.

Effects of temperature and humidity on disease caused by Phoma medicaginis, resistance in some Medicago cultivars and the incidence of seed-borne inoculum

1987 ◽  
Vol 27 (6) ◽  
pp. 851 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Disease Severity ◽  
Post Inoculation ◽  
High Humidity ◽  
Symptom Development ◽  
Resistant Cultivars ◽  
Phoma Medicaginis ◽  
Temperature And Humidity ◽  
Effects Of Temperature ◽  
Moderate Resistance ◽  
Medicago Species

The effects of temperature and humidity on the development of Phoma blackstem disease (caused by Phoma medicagrnis) on Medicago spp. were investigated. Disease was greatest at 21/16� (12-h photoperiod), followed by 18/13�C, and least at 15/10�. Extending the period of post-inoculation high humidity increased disease severity and the rate of symptom development. Although no Medicago species or cultivars tested were highly resistant, there were large differences among both different species and cultivars of the same species, with several showing moderate resistance. Results show there is potential for control of Phoma blackstem through breeding and/or selecting resistant cultivars. Phoma medicaginis was associated with all but 1 of the 16 seed lines tested and the incidence of seed-borne contamination ranged from 0 to 38%.

scholarly journals Phytophthora Root Rot of Blueberry Increases with Frequency of Flooding

HortScience ◽  
1999 ◽  
Vol 34 (4) ◽  
pp. 693-695 ◽  
Author(s):  
Amal de Silva ◽  
Keith Patterson ◽  
Craig Rothrock ◽  
Ron McNew
Keyword(s):  
Disease Severity ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Disease Incidence ◽  
Severe Disease ◽  
Vaccinium Corymbosum ◽  
Root Infection ◽  
Phytophthora Root Rot ◽  
Severity Rating ◽  
Linear Relationships

Phytophthora root rot is a severe disease on blueberry (Vaccinium corymbosum L.) in poorly drained soils. Little is known about how mulching and frequent waterlogging affect disease severity in blueberries. Phytophthora cinnamomi Rands was grown on rice hulls, which were incorporated into the soil at the rate of 10% (v:v). Waterlogging conditions were imposed for 48 hours 1 week after planting on mulched and nonmulched blueberry plants at weekly, biweekly, and monthly intervals for a total of 3 months. Control plants were not subjected to flooding. The severity of Phytophthora root rot increased with time. Significant linear relationships were found between flooding interval and disease severity rating of shoot, percentage of root infection, and shoot and root dry weights of plants. Disease symptoms were minimal in control plants, but shoot disease rating and percentage of root infection were high in mulched and nonmulched plants that were flooded every week. Shoot and root dry weights were higher in 1997 than in 1996. In 1996, mulched plants had higher shoot dry weights than did nonmulched plants. Disease incidence was higher with weekly and biweekly flooding than with monthly or no flooding. However, mulching did not affect root infection.

Resistance in annual Medicago species to Phoma medicaginis under controlled environment and field conditions

1990 ◽  
Vol 30 (2) ◽  
pp. 209 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Temperature Regime ◽  
Environmental Conditions ◽  
Field Data ◽  
Plant Age ◽  
Controlled Environment ◽  
Temperature Regimes ◽  
Phoma Medicaginis ◽  
Annual Medicago ◽  
Medicago Species ◽  
Line Resistance

Seven Medicago species, comprising 11 cultivars and 9 seed lines, were screened for resistance to Phoma black stem disease (caused by Phoma medicaginis) at 3 temperature regimes (day/night) of 15/10, 17.5/12.5 and 20/15�C and at 3 plant ages under controlled environment conditions. The same cultivars and lines were screened in the field over 2 seasons. There were large differences among species, and between cultivars and lines of any 1 species, in the severity of Phoma black stem disease on plants 1,4 and 10 weeks of age and at the 3 temperature regimes under controlled environment conditions, and in field screenings. Under controlled environmental conditions the cultivar and line resistance rankings were influenced by plant age, in particular, and also by the temperature regime. Cultivar and line resistance to P. medicaginis on 10-week-old plants under controlled environment conditions was correlated with some field results but resistance to this disease on 1- and 4-week-old plants was not correlated with field data.

Interactions between helicobacter-induced inflammation acute changes in the gut microbiota, and colorectal cancer in Smad3-/- mice

2020 ◽  
Author(s):  
◽  
Annie E. Wolfie
Keyword(s):  
Colorectal Cancer ◽  
Gut Microbiota ◽  
Disease Severity ◽  
Community Dynamics ◽  
Inflammatory Diseases ◽  
Disease Incidence ◽  
Severe Disease ◽  
Underlying Mechanism ◽  
Post Inoculation ◽  
Disease Development

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI--COLUMBIA AT REQUEST OF AUTHOR.] Colorectal cancer (CRC) is the second leading cause of cancer-related mortality worldwide, accounting for 551,269 deaths in 2018 alone. One subset of CRC, colitis associated CRC (CAC), develops as a sequela to chronic inflammatory diseases of the bowel. The underlying mechanism of CAC is poorly understood, but prognosis is poor due to difficulty of detection. Surveillance strategies are invasive and expensive. Risk factors of CAC include inflammatory bowel disease (IBD), diet, smoking, environment, and obesity--all of which impact or are impacted by the gut microbiota (GM), making the GM a prime target for understanding the etiology of CAC in order to develop preventative measures. Using the Smad3-/- CAC model, which requires inoculation of pathobiont Helicobacter spp., we tested the ability of the Th17-enhancing commensal Candidatus Savagella, more commonly denoted as Segmented Filamentous Bacteria (SFB), to influence the incidence and severity of CAC. To document the composition of the gut microbiota during CRC development and identify taxa associated with disease, fecal samples were collected before and throughout disease development and characterized via 16S rRNA sequencing. While there were no significant SFB-dependent effects on disease incidence or severity, SFB were found to exert a sex-dependent protective effect in male mice. Furthermore, SFB stabilized the GM against Helicobacter-induced changes post inoculation, resulting in a shift in disease association from Helicobacter spp. to Escherichia coli. These data support sex-dependent SFB-mediated effects on CRC risk, and highlight the complex community dynamics within the GM during exposure to inflammatory pathobionts. In order to artificially modulate disease severity, we repeated the above experiments using Smad3-/- mice rederived onto different GM backgrounds, using a technique called complex microbiota targeted rederivation (CMTR). Smad3-/- mice harboring distinct GM profiles termed GM1, GM2, and GM4 were similarly inoculated with Helicobacter spp. and followed longitudinally through disease development or lack thereof. We hypothesized that GM1 and 2 would develop the most severe disease, due to lack of richness and diversity. There was no difference in disease penetrance between the GM profiles, and no pre-disposing GM profile was found at pre-inoculation or early timepoints. However, GM2 developed greater disease severity than GM1 and GM4. Looking at static and dynamic differences between CRC- and CRC+ groups of each GM revealed OTUs, genera, and families which differed in disease development. Network construction analysis using overlapping timepoints from early to late, revealed that overall CRC+ bacterial communities had fewer connections than their CRC- counterparts. This was most striking in GM2 CRC+, which could account for the increased disease severity in this GM profile.

scholarly journals Increased SAR-CoV-2 shedding associated with reduced disease severity despite continually emerging genetic variants

2021 ◽  
Author(s):  
Cynthia Y. Tang ◽  
Yang Wang ◽  
Cheng Gao ◽  
David R. Smith ◽  
Jane A. McElroy ◽  
...  
Keyword(s):  
Disease Severity ◽  
Genetic Variants ◽  
Severe Disease ◽  
Fold Increase ◽  
Rural Regions ◽  
Multiple Introductions ◽  
Viral Genomes ◽  
Viral Loads ◽  
Viral Shedding ◽  
Hospital Stays

ABSTRACTSince the first report of SARS-CoV-2 in December 2019, genetic variants have continued to emerge, complicating strategies for mitigating the disease burden of COVID-19. Positive SARS-CoV-2 nasopharyngeal swabs (n=8,735) were collected from Missouri, USA, from March-October 2020, and viral genomes (n=178) were sequenced. Hospitalization status and length of stay were extracted from medical charts of 1,335 patients and integrated with emerging genetic variants and viral shedding analyses for assessment of clinical impacts. Multiple introductions of SARS-CoV-2 into Missouri, primarily from Australia, Europe, and domestic states, were observed. Four local lineages rapidly emerged and spread across urban and rural regions in Missouri. While the majority of Missouri viruses harbored Spike-D614G mutations, a large number of unreported mutations were identified among Missouri viruses, including seven in the RNA-dependent RNA polymerase complex and Spike protein that were positively selected. A 15.6-fold increase in viral RNA levels in swab samples occurred from March to May and remained elevated. Accounting for other comorbidities, individuals test-positive for COVID-19 with high viral loads were less likely to be hospitalized (odds ratio=0.39, 95% confidence interval [CI]=0.20, 0.77) and had shorter hospital stays (hazard ratio=0.34, p=0.003) than those with low viral loads. Overall, the first eight months of the pandemic in Missouri saw multiple locally acquired mutants emerge and dominate in urban and rural locations. Although we were unable to find associations between specific variants and greater disease severity, Missouri COVID-positive individuals that presented with increased viral shedding had less severe disease by several measures.

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