quarta-feira, 19 de junho de 2019
O elo entre o científico e o popular.
Texto: Bióloga Pamella de Andrade Ferreira
Quando pensamos em ciência, algumas questões são importantes de serem refletidas: O que é científico? Quem o produz e como ele é construído?
Rubem Alves aborda essas questões de forma incisiva, expondo que a ciência é o que os próprios cientistas produzem, ou seja, é uma atividade de construção de conhecimentos exercida por um grupo definido. Para elucidar melhor, o autor ainda elabora uma metáfora: o saber científico pode ser apontado como tudo àquilo que pode ser pescado no “rio da realidade” com uma rede específica denominada método científico.
Contudo, toda rede, independente de sua seletividade e eficácia de sua malha, deixa passar mais do que pode apanhar. Infelizmente, a pesquisa científica muitas vezes se restringe apenas ao que fica retido na sua rede, ignorando os fenômenos que não podem ser controlados e desconsiderando o que não foi pescado e não pode ser explicado com as ferramentas utilizadas.
Com isso, se dá a importância de uma vertente de pesquisa que tenha o intuito de investigar e compreender outras categorias de conhecimento, que não são reconhecidas pelos métodos científicos convencionais, como o saber tradicional presente nas diversas culturas e etnias, que se originam a partir das vivências particulares e se fundamentam empiricamente ao longo das gerações.
Que a verdade seja dita: o uso das plantas medicinais tem base empírica e berço nas comunidades originárias e tradicionais. A fitoterapia nasceu do conhecimento tradicional: das observações que as comunidades faziam acerca da natureza e do comportamento animal, da intuição e da transmissão oral desses conhecimentos que perpassaram de geração em geração compondo uma vasta cultura do saber.
Para contemplar e valorizar essa riqueza de conhecimento existe a etnobotânica, que é uma linha de pesquisa endereçada não apenas a coleta de dados, mas sim a compreender o modo como as plantas são vistas e utilizadas pelas comunidades e pela cultura local, analisando essa inter-relação entre os indivíduos e as plantas presentes no ambiente, incentivando o resgate e a valorização dos conhecimentos tradicionais e a preservação dos recursos, servindo assim como um elo entre a linguagem científica e a experiência popular.
O elo entre o científico e o popular.
Quando pensamos em ciência, algumas questões são importantes de serem refletidas: O que é científico? Quem o produz e como ele é construído?
Rubem Alves aborda essas questões de forma incisiva, expondo que a ciência é o que os próprios cientistas produzem, ou seja, é uma atividade de construção de conhecimentos exercida por um grupo definido. Para elucidar melhor, o autor ainda elabora uma metáfora: o saber científico pode ser apontado como tudo àquilo que pode ser pescado no “rio da realidade” com uma rede específica denominada método científico.
Contudo, toda rede, independente de sua seletividade e eficácia de sua malha, deixa passar mais do que pode apanhar. Infelizmente, a pesquisa científica muitas vezes se restringe apenas ao que fica retido na sua rede, ignorando os fenômenos que não podem ser controlados e desconsiderando o que não foi pescado e não pode ser explicado com as ferramentas utilizadas.
Com isso, se dá a importância de uma vertente de pesquisa que tenha o intuito de investigar e compreender outras categorias de conhecimento, que não são reconhecidas pelos métodos científicos convencionais, como o saber tradicional presente nas diversas culturas e etnias, que se originam a partir das vivências particulares e se fundamentam empiricamente ao longo das gerações.
Que a verdade seja dita: o uso das plantas medicinais tem base empírica e berço nas comunidades originárias e tradicionais. A fitoterapia nasceu do conhecimento tradicional: das observações que as comunidades faziam acerca da natureza e do comportamento animal, da intuição e da transmissão oral desses conhecimentos que perpassaram de geração em geração compondo uma vasta cultura do saber.
Para contemplar e valorizar essa riqueza de conhecimento existe a etnobotânica, que é uma linha de pesquisa endereçada não apenas a coleta de dados, mas sim a compreender o modo como as plantas são vistas e utilizadas pelas comunidades e pela cultura local, analisando essa inter-relação entre os indivíduos e as plantas presentes no ambiente, incentivando o resgate e a valorização dos conhecimentos tradicionais e a preservação dos recursos, servindo assim como um elo entre a linguagem científica e a experiência popular.
Quando pensamos em ciência, algumas questões são importantes de serem refletidas: O que é científico? Quem o produz e como ele é construído?
Rubem Alves aborda essas questões de forma incisiva, expondo que a ciência é o que os próprios cientistas produzem, ou seja, é uma atividade de construção de conhecimentos exercida por um grupo definido. Para elucidar melhor, o autor ainda elabora uma metáfora: o saber científico pode ser apontado como tudo àquilo que pode ser pescado no “rio da realidade” com uma rede específica denominada método científico.
Contudo, toda rede, independente de sua seletividade e eficácia de sua malha, deixa passar mais do que pode apanhar. Infelizmente, a pesquisa científica muitas vezes se restringe apenas ao que fica retido na sua rede, ignorando os fenômenos que não podem ser controlados e desconsiderando o que não foi pescado e não pode ser explicado com as ferramentas utilizadas.
Com isso, se dá a importância de uma vertente de pesquisa que tenha o intuito de investigar e compreender outras categorias de conhecimento, que não são reconhecidas pelos métodos científicos convencionais, como o saber tradicional presente nas diversas culturas e etnias, que se originam a partir das vivências particulares e se fundamentam empiricamente ao longo das gerações.
Que a verdade seja dita: o uso das plantas medicinais tem base empírica e berço nas comunidades originárias e tradicionais. A fitoterapia nasceu do conhecimento tradicional: das observações que as comunidades faziam acerca da natureza e do comportamento animal, da intuição e da transmissão oral desses conhecimentos que perpassaram de geração em geração compondo uma vasta cultura do saber.
Para contemplar e valorizar essa riqueza de conhecimento existe a etnobotânica, que é uma linha de pesquisa endereçada não apenas a coleta de dados, mas sim a compreender o modo como as plantas são vistas e utilizadas pelas comunidades e pela cultura local, analisando essa inter-relação entre os indivíduos e as plantas presentes no ambiente, incentivando o resgate e a valorização dos conhecimentos tradicionais e a preservação dos recursos, servindo assim como um elo entre a linguagem científica e a experiência popular.
O elo entre o científico e o popular.
Quando pensamos em ciência, algumas questões são importantes de serem refletidas: O que é científico? Quem o produz e como ele é construído?
Rubem Alves aborda essas questões de forma incisiva, expondo que a ciência é o que os próprios cientistas produzem, ou seja, é uma atividade de construção de conhecimentos exercida por um grupo definido. Para elucidar melhor, o autor ainda elabora uma metáfora: o saber científico pode ser apontado como tudo àquilo que pode ser pescado no “rio da realidade” com uma rede específica denominada método científico.
Contudo, toda rede, independente de sua seletividade e eficácia de sua malha, deixa passar mais do que pode apanhar. Infelizmente, a pesquisa científica muitas vezes se restringe apenas ao que fica retido na sua rede, ignorando os fenômenos que não podem ser controlados e desconsiderando o que não foi pescado e não pode ser explicado com as ferramentas utilizadas.
Com isso, se dá a importância de uma vertente de pesquisa que tenha o intuito de investigar e compreender outras categorias de conhecimento, que não são reconhecidas pelos métodos científicos convencionais, como o saber tradicional presente nas diversas culturas e etnias, que se originam a partir das vivências particulares e se fundamentam empiricamente ao longo das gerações.
Que a verdade seja dita: o uso das plantas medicinais tem base empírica e berço nas comunidades originárias e tradicionais. A fitoterapia nasceu do conhecimento tradicional: das observações que as comunidades faziam acerca da natureza e do comportamento animal, da intuição e da transmissão oral desses conhecimentos que perpassaram de geração em geração compondo uma vasta cultura do saber.
Para contemplar e valorizar essa riqueza de conhecimento existe a etnobotânica, que é uma linha de pesquisa endereçada não apenas a coleta de dados, mas sim a compreender o modo como as plantas são vistas e utilizadas pelas comunidades e pela cultura local, analisando essa inter-relação entre os indivíduos e as plantas presentes no ambiente, incentivando o resgate e a valorização dos conhecimentos tradicionais e a preservação dos recursos, servindo assim como um elo entre a linguagem científica e a experiência popular.
segunda-feira, 17 de junho de 2019
New mutations for herbicide resistance rarer than expected
Date: May 28, 2019 Source: University of Illinois at Urbana-Champaign, News Bureau Summary: New evidence suggests that herbicide resistance in weeds is more likely to occur from pre-existing genetic variation than from new mutations.
After exposing more than 70 million grain amaranth seeds to a soil-based herbicide, researchers were not able to find a single herbicide-resistant mutant. Though preliminary, the findings suggest that the mutation rate in amaranth is very low, and that low-level herbicide application contributes little -- if anything -- to the onset of new mutations conferring resistance, researchers say.
The study is reported in the journal Weed Science.
Any major stress that does not kill a plant can contribute to genetic mutations in its seeds and pollen, said University of Illinois crop sciences professor Patrick Tranel, who led the new research. Even the ultraviolet light in sunlight can stress a plant and increase the likelihood of mutations in its offspring, he said. Such mutations increase genetic diversity, which can be useful to a species' survival.
"Resistance to herbicides comes from genetic variation in a population," Tranel said. "If an individual weed has the right mutation that allows it to survive a particular herbicide, that individual will survive and pass the trait to its progeny."
The relative contribution of new mutations to the problem of herbicide resistance is poorly understood, Tranel said. He and his colleagues hoped to determine the baseline mutation rate for a plant of the genus Amaranthus, a group that includes waterhemp, Palmer amaranth and other problematic agricultural weeds. They also wanted to test whether herbicide applications that failed to kill the plant increased that baseline rate.
The researchers started with a single seed of Amaranthus hypochondriacus, which is closely related to several agricultural weeds but is not known to harbor herbicide-resistance genes. Using a greenhouse to isolate their experiments from potential contamination from other Amaranthus species, the team cultivated this one plant, collected its seeds and began the long process of growing generations of related plants and harvesting the seeds.
"A good plant would produce about 100,000 seeds," Tranel said. "From this one plant, we eventually got more than 70 million seeds."
Despite the laboratory's isolation and the vigilance of the scientists, a few other Amaranthus weed seeds made their way into the experiment.
"These seeds are tiny and cling to things. You can have a seed stuck to your skin and not know it," Tranel said. "One of the students found a weed seed in his eyebrow after he left the greenhouse."
Luckily for the scientists, the seeds of the weedy Amaranthusspecies are black, while their test plants produced only light-colored seeds.
To screen the seeds for herbicide resistance, the researchers spread them over the surface of soil treated with a type of herbicide known as an ALS inhibitor, then waited to see whether any of the seedlings survived. Very few of the test plants overcame the herbicide treatment. Rigorous testing revealed that those rare plants that did survive were the offspring of seeds of weedy amaranth species that already carried the resistance genes.
The experiments verified that the scientists' approach worked well for screening vast numbers of seeds. It also established that the team would have to test many more than 70 million seeds to determine the baseline mutation rate in A. hypochondriacus -- and to figure out if low-level herbicide treatment increases that rate, Tranel said.
Knowing this is essential to developing models that can accurately predict how plants will behave in a field, he said.
"Herbicide resistance is an evolutionary process, and evolutionary processes are mathematical," Tranel said. "If you know more precisely how plants will behave under different environmental conditions, you can develop equations that will predict how fast resistance will evolve."
If, as the study suggests, the mutation rate is much lower than expected, it doesn't mean that herbicide resistance will not occur, he said. "It may be that resistance happens a bit more slowly than previously thought," he said. "But it will still occur."
Story Source:
Materials provided by University of Illinois at Urbana-Champaign, News Bureau. Note: Content may be edited for style and length.
Journal Reference:
Federico A. Casale, Darci A. Giacomini, Patrick J. Tranel. Empirical investigation of mutation rate for herbicide resistance. Weed Science, 2019; 1 DOI: 10.1017/wsc.2019.19
Cite This Page:
University of Illinois at Urbana-Champaign, News Bureau. "New mutations for herbicide resistance rarer than expected." ScienceDaily. ScienceDaily, 28 May 2019. <www.sciencedaily.com/releases/2019/05/190528140113.htm>.
Red and white meats are equally bad for cholesterol
Date: June 4, 2019 Source: University of California - San Francisco Summary: Contrary to popular belief, consuming red meat and white meat such as poultry, have equal effects on blood cholesterol levels, according to a new study.
Contrary to popular belief, consuming red meat and white meat such as poultry, have equal effects on blood cholesterol levels, according to a study published today in the American Journal of Clinical Nutrition.
The study, led by scientists at Children's Hospital Oakland Research Institute (CHORI) -- the research arm of UCSF Benioff Children's Hospital Oakland -- surprised the researchers with the discovery that consuming high levels of red meat or white poultry resulted in higher blood cholesterol levels than consuming a comparable amount of plant proteins. Moreover, this effect was observed whether or not the diet contained high levels of saturated fat, which increased blood cholesterol to the same extent with all three protein sources.
"When we planned this study, we expected red meat to have a more adverse effect on blood cholesterol levels than white meat, but we were surprised that this was not the case -- their effects on cholesterol are identical when saturated fat levels are equivalent," said the study senior author Ronald Krauss, M.D., senior scientist and director of Atherosclerosis Research at CHORI.
Krauss, who is also a UCSF professor of medicine, noted that the meats studied did not include grass-fed beef or processed products such as bacon or sausage; nor did it include fish.
But the results were notable, as they indicated that restricting meat altogether, whether red or white, is more advisable for lowering blood cholesterol levels than previously thought. The study found that plant proteins are the healthiest for blood cholesterol.
This study, dubbed the APPROACH (Animal and Plant Protein and Cardiovascular Health) trial, also found that consuming high amounts of saturated fat increased concentrations of large cholesterol-enriched LDL particles, which have a weaker connection to cardiovascular disease than smaller LDL particles.
Similarly, red and white meat increased amounts of large LDL in comparison to nonmeat diets. Therefore, using standard LDL cholesterol levels as the measure of cardiovascular risk may lead to overestimating that risk for both higher meat and saturated fat intakes, as standard LDL cholesterol tests may primarily reflect levels of larger LDL particles.
Consumption of red meat has become unpopular during the last few decades over concerns about its association with increased heart disease. Government dietary guidelines have encouraged the consumption of poultry as a healthier alternative to red meat.
But there had been no comprehensive comparison of the effects of red meat, white meat and nonmeat proteins on blood cholesterol until now, Krauss said. Nonmeat proteins such as vegetables, dairy, and legumes, such as beans, show the best cholesterol benefit, he said.
"Our results indicate that current advice to restrict red meat and not white meat should not be based only on their effects on blood cholesterol," Krauss said. "Indeed, other effects of red meat consumption could contribute to heart disease, and these effects should be explored in more detail in an effort to improve health."
Story Source:
Materials provided by University of California - San Francisco. Original written by Lorna Fernandes. Note: Content may be edited for style and length.
Journal Reference:
Nathalie Bergeron, Sally Chiu, Paul T Williams, Sarah M King, Ronald M Krauss. Effects of red meat, white meat, and nonmeat protein sources on atherogenic lipoprotein measures in the context of low compared with high saturated fat intake: a randomized controlled trial. The American Journal of Clinical Nutrition, 2019; DOI: 10.1093/ajcn/nqz035
Cite This Page:
University of California - San Francisco. "Red and white meats are equally bad for cholesterol." ScienceDaily. ScienceDaily, 4 June 2019. <www.sciencedaily.com/releases/2019/06/190604084840.htm>.
Unsalted tomato juice may help lower heart disease risk
Date: June 5, 2019 Source: Wiley Summary: Drinking unsalted tomato juice lowered blood pressure and LDL cholesterol in Japanese adults at risk of cardiovascular disease.
In a study published in Food Science & Nutrition, drinking unsalted tomato juice lowered blood pressure and LDL cholesterol in Japanese adults at risk of cardiovascular disease.
In the study, 184 male and 297 female participants were provided with as much unsalted tomato juice as they wanted throughout one year. At the end of the study, blood pressure in 94 participants with untreated prehypertension or hypertension dropped significantly: systolic blood pressure lowered from an average of 141.2 to 137.0 mmHg, and diastolic blood pressure lowered from an average of 83.3 to 80.9 mmHg. LDL cholesterol levels in 125 participants with high cholesterol decreased from an average of 155.0 to 149.9 mg/dL. These beneficial effects were similar among men and women and among different age groups.
"To the best of our knowledge, the current study is the first to investigate the effects of tomato or tomato product intake on cardiovascular disease risk markers over the course of a year and over a wide age range," the authors wrote.
Story Source:
Materials provided by Wiley. Note: Content may be edited for style and length.
Journal Reference:
Tamami Odai, Masakazu Terauchi, Daisaku Okamoto, Asuka Hirose, Naoyuki Miyasaka. Unsalted tomato juice intake improves blood pressure and serum low‐density lipoprotein cholesterol level in local Japanese residents at risk of cardiovascular disease. Food Science & Nutrition, 2019; DOI: 10.1002/fsn3.1066
Cite This Page:
Wiley. "Unsalted tomato juice may help lower heart disease risk." ScienceDaily. ScienceDaily, 5 June 2019. <www.sciencedaily.com/releases/2019/06/190605100354.htm>.
New research decodes plant defense system, with an eye on improving farming and medicine
Findings reveal new genetic links between plants' circadian clock and immunity systems
Date: June 13, 2019 Source: University of Maryland Baltimore County Summary: The plant circadian clock determines when certain defense responses are activated (often timed with peak activity of pests), and compounds used in defense affect the clock. New findings show how the clock regulates stomata opening/closure for defense, and how the defensive compound jasmonic acid influences the clock. This could lead to plants that are better at defending themselves, reducing the need for pesticides, and potentially influencing timing for human medical treatment.
UMBC's Hua Lu, professor of biological sciences, and colleagues have found new genetic links between a plant's circadian rhythm (essentially, an internal clock) and its ability to fend off diseases and pests. The findings were 10 years in the making and published in Nature Communicationsthis week. The results could eventually lead to plants that are more resistant to disease-causing pathogens and better treatment for human diseases.
"It's quite cool," Lu says, "because, in both plants and animals, people are beginning to study the crosstalk between the circadian clock and the immunity system."
Timing is everything
In response to daily attacks from bacteria, fungi, and other pests, plants have evolved various strategies to protect themselves. Plants may close their stomata -- small openings in the waxy coating on their leaves -- to prevent entry by some bacteria. They might produce chemicals such as salicylic acid and jasmonic acid to repel bacteria and insects. They also make a large number of proteins that are important for successful defense.
Actions like closing stomata, producing salicylic acid, and more happen on a daily schedule, often peaking at the times when certain pathogens and pests are most likely to be active. The rhythmic nature of plant defense suggests plants are coordinating their internal clock with their defense system to increase the effectiveness of their defensive actions.
In this study, Lu and colleagues found for the first time that LUX, a central gene in the plant circadian clock, is important for regulating the opening and closing of the stomata at specific times of day, and also for activating defense mediated by salicylic acid and jasmonic acid.
In a typical plant, the stomata open during the day, to enable exchange of gases required for photosynthesis. Then they close at night, to prevent water loss. The stomata also close in response to daytime pathogen attacks. They respond minimally to an attack at night, because they're already closed.
However, in plants with a non-functional version of the LUX gene, Lu found that the stomata are open both day and night. During a daytime attack, the stomata stay open wider than normal plants. During a nighttime attack, though, some of the stomata close. This means that plants lacking a functional LUX gene have less control over when their stomata open, allowing more opportunistic pathogens to get in. This distinction indicates that LUX is critical for the timing of the stomata-driven defense response, tying defense to the circadian clock in a new way.
Lu's research also dives into the relationship between the LUX gene and the defense chemicals salicylic acid and jasmonic acid. While it was known that the circadian clock can regulate defense responses, this paper shows that the reverse is also true: "A properly tuned circadian clock is important for defense activation. When defense is activated, it then can feed back to regulate the circadian clock," Lu says.
The research team specifically showed that the presence of LUX is needed for normal jasmonic acid signaling. In turn, jasmonic acid also affects expression of LUX and the circadian clock. This reciprocal regulation between the circadian clock and defense signaling helps plants balance their energy use for normal growth and development and defense responses.
From farms to pharma
Lu is interested in pursuing further research to figure out how timing influences the plant defense system. How does the circadian clock affect multiple aspects of defense responses? What molecules from pathogens and pests interfere with a plant's circadian clock and subsequently limit its ability to protect itself? Better understanding how clock genes control plant defense and how pathogens interact with plant defense systems could benefit agriculture and beyond.
"Pathogens are everywhere all the time. Often the most active form of a pathogen varies during a day. Also, plants could have different defense strategies at different times of day," explains Lu. "So, when is the best time to apply pesticides? That could depend on the pathogen, its infection mode, and the behavior of your crop plants. I think that field tests are needed to figure out the best time to apply chemicals to achieve the most efficacy in preventing infection or the spread of infection."
Less pesticide use overall would reduce runoff of chemicals into waterways and lower costs for farmers. Reduced use of antibiotics could help stem antibiotic resistance, which would benefit humans, too.
Plus, plants aren't the only ones whose immune system activity fluctuates throughout the day. Animal systems also have daily cycles. So, "similar ideas can be applied to the medical field," Lu says.
There are similarities between the ways plants and animals interact with their pathogens and pests at the molecular level. Maybe in the future, your prescription will come with specific timing instructions, or your surgery will be scheduled based on your immune system activity.
Science in action
Lu says all of her research, and this multi-part paper in particular, is driven by her lab members. "It's great to work with this many dedicated people," she says. "Without them, I couldn't do it."
That includes postdoctoral fellow Chong Zhang, who is now employed by the USDA, and current postdoc Min Gao, who are co-first authors on the new paper. Five undergraduate students and a high school student also contributed to this long-term project. Some of the experiments required testing every four hours over a 24-hour period, which meant someone was sleeping on a couch in the lab when they were underway.
Overall, Lu's team members are driven by the potential benefits their work could contribute to society. They are excited by the prospect of improving crop yields to feed a growing population, reducing pollution, or reducing side effects for human medical treatment through improved timing and dosing.
"This field interests me because I can see my work have some practical applications, and I think that's important," Lu says. "That should be every scientist's goal -- to use your knowledge in real life."
Story Source:
Materials provided by University of Maryland Baltimore County. Note: Content may be edited for style and length.
Journal Reference:
Chong Zhang, Min Gao, Nicholas C. Seitz, William Angel, Amelia Hallworth, Linda Wiratan, Omar Darwish, Nadim Alkharouf, Teklu Dawit, Daniela Lin, Riki Egoshi, Xiping Wang, C. Robertson McClung, Hua Lu. LUX ARRHYTHMO mediates crosstalk between the circadian clock and defense in Arabidopsis. Nature Communications, 2019; 10 (1) DOI: 10.1038/s41467-019-10485-6
Cite This Page:
University of Maryland Baltimore County. "New research decodes plant defense system, with an eye on improving farming and medicine: Findings reveal new genetic links between plants' circadian clock and immunity systems." ScienceDaily. ScienceDaily, 13 June 2019. <www.sciencedaily.com/releases/2019/06/190613103122.htm>.
Interactions between plant and insect-infecting viruses
Date: June 13, 2019 Source: Boyce Thompson Institute Summary: Aphids and the plant viruses they transmit cause billions of dollars in crop damage every year. Researchers are examining this relationship at the molecular level, which could lead to new methods for controlling the pests. The researchers uncovered what may be the first example of cooperation between a plant virus and an insect virus to increase their likelihood to spread.
Aphids and the plant viruses they transmit cause billions of dollars in crop damage around the world every year. Researchers in Michelle Heck's lab at the USDA Agricultural Research Service and Boyce Thompson Institute are examining the relationship at the molecular level, which could lead to new methods for controlling the pests.
Heck's group used recently developed small RNA sequencing techniques to better understand how plant viruses interact with aphids. In an unanticipated discovery, Heck and her team uncovered what may be the first example of a plant virus and an insect virus cooperating to increase the likelihood that both viruses will spread to other plant and aphid hosts.
The work was published in the May 22 issue of Phytobiomesjournal. The researchers focused on the green peach aphid (Myzus persicae), which transmits more than 100 different plant viruses and feeds on a wide variety of crops, including peaches, tomatoes, potatoes, cabbage, corn and numerous others.
Potato leafroll virus (PLRV) is of particular concern because it can reduce potato yield by more than 50%, causing 20 million tons of annual global yield losses.
"The most interesting finding of this research is that PLRV suppressed the aphid's immune system, and this suppression was mediated by a single virus protein, the P0 protein," says Jennifer Wilson, a co-first author on the paper. Wilson is a PhD candidate in the School of Integrative Plant Science (SIPS) at Cornell University and is conducting her thesis research with Dr. Heck.
P0 is a PLRV protein that is expressed inside plant tissue but not inside the aphids. While P0 had been previously shown to suppress plants' immune systems, the protein's impact on the insect's immune system was a surprise to the researchers.
"We don't know if the aphids ingest P0 from the plant or not, but we do know that when P0 is present in the plant, the aphids' immune systems are suppressed," explains Wilson.
One critical result of the insect's immune system being hampered is an increase in the proliferation of an insect virus, Myzus persicae densovirus (MpDNV). The researchers also found that aphids with more copies of MpDNV were more likely to have wings.
Because green peach aphids rarely have wings until the weather turns colder in the fall, this increase in winged insects could mean increased spread of PLRV and MpDNV to new hosts all summer long, a synergistic effect that wouldn't happen as much if the aphids were infected with only one of the viruses.
"We think we have found the first example of cooperation between a plant virus and an insect virus," Wilson says. "This cooperation may lead to increased transmission of both viruses."
Wilson and Heck are currently working to test this hypothesis by repeating the experiments in aphids not infected with MpDNV, which Wilson collected last summer from farms in upstate New York.
Future work could include figuring out how MpDNV and the P0 protein could be used to control virus transmission by aphids.
"Developing strategies to block virus transmission in the field is a major goal of our research program," said Heck, also an adjunct assistant professor in SIPS. "Wilson's thesis work is paradigm shifting. Stay tuned for more exciting stuff from her in the near future."
Story Source:
Materials provided by Boyce Thompson Institute. Note: Content may be edited for style and length.
Journal Reference:
Patricia V. Pinheiro, Jennifer R. Wilson, Yi Xu, Yi Zheng, Ana Rita Rebelo, Somayeh Fattah-Hosseini, Angela Kruse, Rogerio Santos Dos Silva, Yimin Xu, Matthew Kramer, James Giovannoni, Zhangjun Fei, Stewart Gray, Michelle Heck. Plant Viruses Transmitted in Two Different Modes Produce Differing Effects on Small RNA-Mediated Processes in Their Aphid Vector. Phytobiomes Journal, 2019; 3 (1): 71 DOI: 10.1094/PBIOMES-10-18-0045-R
Cite This Page:
Boyce Thompson Institute. "Interactions between plant and insect-infecting viruses." ScienceDaily. ScienceDaily, 13 June 2019. <www.sciencedaily.com/releases/2019/06/190613103142.htm>.
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