Systemic Infection by Fusarium verticillioides in Maize Plants Grown Under Three Temperature Regimes

Fusarium verticillioides causes seedling decay, stalk rot, ear rot, and mycotoxin contamination (primarily fumonisins) in maize. Systemic infection of maize plants by F. verticillioides can lead to kernel infection, but the frequency of this phenomenon has varied widely among experiments. Variation in the incidence of systemic infection has been attributed to environmental factors. In order to better understand the influence of environment, we investigated the effect of temperature on systemic development of F. verticillioides during vegetative and reproductive stages of plant development. Maize seeds were inoculated with a green fluorescent protein-expressing strain of F. verticillioides, and grown in growth chambers under three different temperature regimes. In the vegetative-stage and reproductive-stage experiments, plants were evaluated at tasseling (VT stage), and at physiological maturity (R6 stage), respectively. Independently of the temperature treatment, F. verticillioides was reisolated from nearly 100% of belowground plant tissues. Frequency of reisolation of the inoculated strain declined acropetally in aboveground internodes at all temperature regimes. At VT, the high-temperature treatment had the highest systemic development of F. verticillioides in aboveground tissues. At R6, incidence of systemic infection was greater at both the high- and low-temperature regimes than at the average-temperature regime. F. verticillioides was isolated from higher internodes in plants at R6, compared to stage VT. The seed-inoculated strain was recovered from kernels of mature plants, although incidence of kernel infection did not differ significantly among treatments. During the vegetative growth stages, temperature had a significant effect on systemic development of F. verticillioides in stalks. At R6, the fungus reached higher internodes in the high-temperature treatment, but temperature did not have an effect on the incidence of kernels (either symptomatic or asymptomatic) or ear peduncles infected with the inoculated strain. These results support the role of high temperatures in promoting systemic infection of maize by F. verticillioides, but plant-to-seed transmission may be limited by other environmental factors that interact with temperature during the reproductive stages.

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The physiological consequences of varied heat exposure events in adultMyzus persicae: a single prolonged exposure compared to repeated shorter exposures

PeerJ ◽

10.7717/peerj.2290 ◽

2016 ◽

Vol 4 ◽

pp. e2290 ◽

Cited By ~ 10

Author(s):

Behnaz Ghaedi ◽

Nigel R. Andrew

Keyword(s):

High Temperature ◽

Recovery Time ◽

Prolonged Exposure ◽

Heat Exposure ◽

Temperature Tolerance ◽

Temperature Treatment ◽

High Temperature Treatment ◽

Exposure Group ◽

Temperature Regimes ◽

Heating Event

The study of environmental stress tolerance in aphids has primarily been at low temperatures. In these cases, and in the rare cases of high temperature tolerance assessments, all exposures had been during a single stress event. In the present study, we examined the physiological consequences of repeated high temperature exposure with recovery periods between these stress events inMyzus persicae. We subjected individuals to either a single prolonged three hour heating event, or three one hour heating events with a recovery time of 24 h between bouts. Aphids exposed to repeated bouts of high temperatures had more glucose and higher expression of proteins and osmolyte compounds, such as glycerol, compared to the prolonged exposure group. However, aphids exposed to the repeated high temperature treatment had reduced sources of energy such as trehalose and triglyceride compounds than the prolonged exposure group. Recovery time had more physiological costs (based on production of more protein and consumption of more trehalose and triglyceride) and benefits (based on production of more osmolytes) in repeated high temperature treatments. As aphids are known to respond differently to constant versus ‘natural’ fluctuating temperature regimes, conclusions drawn from constant temperature data sets may be problematic. We suggest future experiments assessing insect responses to thermal stress incorporate a repeated stress and recovery pattern into their methodologies.

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Influence of Inoculation Method on Systemic Fusarium moniliforme Infection of Maize Plants Grown from Infected Seeds

Plant Disease ◽

10.1094/pdis.1997.81.2.211 ◽

1997 ◽

Vol 81 (2) ◽

pp. 211-216 ◽

Cited By ~ 49

Author(s):

G. P. Munkvold ◽

W. M. Carlton

Keyword(s):

Fusarium Moniliforme ◽

Field Experiments ◽

Systemic Infection ◽

Original Strain ◽

Infected Seed ◽

Kernel Infection ◽

Spray Inoculation ◽

Important Pathway ◽

Maize Plants ◽

Systemic Development

Two greenhouse and two field experiments were conducted in 1994 and 1995 to quantify the incidence of maize kernel infection resulting from systemic infection of maize plants by Fusarium moniliforme. Seeds were infected by two methods: (i) spray-inoculation of maize silks during seed development (field-infected), and (ii) soak-inoculation of mature seeds in a spore suspension (laboratory-infected). Plants were grown from infected seeds and assayed for systemic infection by the seed-inoculated strain, determined by vegetative compatibility of recovered isolates with the original strain. The seed-inoculated strain was recovered from stalks and kernels of plants grown from both types of infected seed. Mature plants grown from field-infected seeds had a higher percentage of their kernels infected with the seed-inoculated strain compared with plants from laboratory-infected seed. Mean incidence of infection by the seed-inoculated strain was 9.9 to 29.4% of all kernels (33.0 to 55.9% of F. moniliforme-infected kernels) in the plants grown from field-infected seed. Some plants from infected seed were subsequently silk-inoculated, and the silk-inoculated strain was recovered from a much higher percentage of kernels (26.5 to 37.5% of all kernels or 77.9 to 78.4% of F. moniliforme-infected kernels) than was the seed-inoculated strain; furthermore, silk inoculation significantly reduced incidence of kernel infection by the seed-inoculated strain. Seed infection by F. moniliforme resulted in systemic infection of plants and kernels. However, local infection (via silks) was a more important pathway to kernels than was systemic infection, and strains infecting the silks competed successfully against those entering the kernels through systemic development.

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TEMPERATURE AND HUMIDITY EFFECTS ON THE GROWTH AND YIELD OF PEA CULTIVARS

Canadian Journal of Plant Science ◽

10.4141/cjps71-094 ◽

1971 ◽

Vol 51 (6) ◽

pp. 479-484 ◽

Cited By ~ 9

Author(s):

I. L. NONNECKE ◽

N. O. ADEDIPE ◽

D. P. ORMROD

Keyword(s):

High Temperature ◽

Temperature Treatment ◽

Growth And Yield ◽

High Temperature Treatment ◽

Night Temperature ◽

Full Bloom ◽

Dark Skin ◽

Humidity Effects ◽

Temperature Regimes ◽

Yield Responses

The effects of two relative humidities and three temperature regimes on the growth and yield responses of four pea cultivars were investigated. The high day/night temperature regime of 27/17 C, compared with 17/7 C, decreased the number of pods per plant by 46, 65, 66 and 54% in the cultivars Dark Skin Perfection, Nugget, Early Sweet 11 and Elf, respectively. Continued growth at the high temperature decreased pea yield by 50% in Dark Skin Perfection and about 70% in the other cultivars. When plants were first grown at 17/7 until full bloom and then subjected to the 27/7 C regime, the high temperature treatment showed no significant effect on growth and yield. Dark Skin Perfection was the least adversely affected by high temperature. No significant differences in growth and yield were observed at 50 and 90% relative humidities.

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