Early detection The EU calls for a strong hand to prevent the spread of 'olive tree Ebola'
Central Europe What role has climate change played in the devastating floods in Germany?
The olive tree is much more than a tree in Mediterranean countries, and not only because of its great economic importance.
It is a cultural symbol in many regions of Spain, Italy, Greece or Portugal under which a threat called
Xylella fastidiosa
looms
.
It is a bacterium from America that was first detected in Europe eight years ago.
It is transmitted by sucking insects when they bite a tree to feed on its sap and once it is installed in it, it clogs the vessels through which the sap circulates from the roots to the leaves, weakening it and even causing its death.
Due to its severity, the disease that it inflicts on trees has been called
olive tree Ebola
,
a term that scientists generally do not like because it is neither a virus nor does it affect people or animals.
In addition, this bacterium not only infects olive trees, it is also destructive to vineyards, almond trees, citrus, coffee or fruit trees.
stone, such as plum or peach tree.
"As a microorganism,
Xylella fastidiosa
is nothing like Ebola
from a scientific point of view, its way of acting is very different. It is a bacterium that causes disease in plantations of interest to humans because both crops and crops are economically important. ornamental plants ", summarizes in a telephone conversation the microbiologist Patricia Bernal Guzmán (Seville, 1977), who has launched a novel investigation to combat this pathogen that causes this disease in crops and for which
there is currently no cure.
To try to develop a treatment that allows ending it
,
Patricia Bernal, who is group leader and Ramón y Cajal researcher in the Department of Microbiology of the Faculty of Biology of the University of Seville, has the 40,000 euros that he has just granted the BBVA Foundation through one of the 59 Leonardo scholarships for researchers and cultural creators between the ages of 30 and 45.
Bernal is a specialist in biocontrol, which means that she is
an expert in that pathogens do not reign at their ease
.
And basically what you are going to do in your laboratory is to use a bacterium that exists in nature to fight another, without using pesticides or other chemicals.
"I am going to study the capacity of
Pseudomonas putida
KT2440, which is a safe bacterium, very well studied and with a great capacity to kill plant pathogens, to fight against bacterium
X. fastidiosa
", he summarizes.
The bacterium 'Pseudomonas putida' secretes toxic substances for other bacteria PATRICIA BERNALMUNDO
Its strategy is therefore based on using toxic molecules that secrete harmless microorganisms to combat pathogenic microorganisms. "You have two bacteria fighting." The
Pseudomonas putida
KT2440 strain shoots toxins at other bacteria to kill them. It has up to three different 'weapons' with different toxins ", details the scientist, who in previous publications has already shown that it is effective in eliminating other types of pathogens that infect crops such as tomatoes, beans or peas
For example, says Bernal, this bacterium very effectively eliminates
Pseudomonas savastanoi,
which causes tuberculosis in olive
trees
;
Pseudomonas syringae,
which infects a wide range of species including tomatoes, beans, or peas;
Pectobacterium carotovorum,
which rots different tubers, or
Xanthomonas campestris,
which
causes diseases such
as almond, peach, cherry or plum.
"The advantage of the biocontrol over current methods to prevent pests, which are mainly chemicals such as pesticides, is that biological agents such as bacteria
Pseudomonas putida
are not a threat to the -no environment pollute or soil or groundwater - nor for the health of animals and people, and therefore they are important for sustainable agriculture ", he argues.
The last name of
X. fastidiosa
, by the way, is not due to the problems it generates in the field, but to the difficulty in growing it in the laboratory and its name,
Xylella,
comes from the place where the xylem of plants inhabits .
Different strains of 'X.
annoying '
"The bacterium
X. fastidiosa
has been known for a long time in America, where it causes great problems in vineyards in the US and in citrus fruit in Brazil.
Different strains of the same bacterial species cause problems in different crops," he
says.
As the microbiologist reviews, the bacterium was described for the first time in America, in 1987, as the cause of Pierce's disease in the vine, known since the 19th century.
It spread throughout the American continent, from northern Canada to southern Argentina, causing multimillion-dollar losses.
The bacteria 'Xylella fastidiosa' in the laboratory PATRICIA BERNALMUNDO
However,
"the strain of
X. fastidiosa
that became most famous was the one that reached southern Italy, first in the Apulia region, where it was detected in 2013 and
devastated thousands of hectares of olive trees, in addition to affecting another 30 host plants ", he points out. In 2015, the bacterium was detected on the island of Corsica and in 2016, in the south of France, affecting mainly ornamental plants and wild species of the Mediterranean scrub. In 2016 it was Spain's turn, specifically in the Balearic Islands (Mallorca, Menorca and Ibiza), where wild olive, olive, almond and vine plants were found, among others. In 2017 the first cases were detected in the Iberian Peninsula, specifically in different municipalities of Alicante, mainly affecting almond trees.In April 2018, two isolated cases were described, one in an olive tree in Madrid and the other in ornamental
polygala
plants.
in a greenhouse in El Ejido in Almería.
Finally, in 2019 it was detected in Portugal, in a region near Porto ".
Fortunately, says Bernal, the strain that in Italy has infected at least 200,000 hectares of land in which there are around 20 million olive trees, some centenarians, has not yet reached Spain: "
Many preventive measures are being taken
to avoid that the dramatic situation that has occurred there occurs in our country.
Because in Andalusia in particular and in Spain in general, says the microbiologist,
the loss of heritage represented by olive groves "would be invaluable
and therefore it is crucial to curb the pathogen and prevent it from being introduced into areas of our country free of the disease. bacteria, or that it spreads from infected areas to the rest of our country and the Mediterranean.
Patricia Bernal Guzmán in her laboratory at the University of Seville FBBVA
X. fastidiosa
has been a quarantine strain in the European Union since 2000, so it cannot be handled in any laboratory. Currently in Spain there are less than half a dozen biosafety facilities with the permits and with the necessary equipment to work with it. One of them is directed by Blanca Landa, from the Institute of Sustainable Agriculture of Córdoba (CSIC), who is part of this research.
As Landa points out through an email, in Spain samples are carried out continuously throughout the year both in fields and in greenhouses within the framework of the Contingency Plan of the Ministry of Agriculture, Fisheries and Food, and whose competences at the level of Plant Health have different autonomies. In addition, at the European level there is a control (audits are carried out) to control the procedure and ensure that the containment measures applied by each country are adequate. "As a consequence of this intense sampling in recent years, the number of host plants where
Xylella
has been detected has increased.
.
When a positive is detected, the vegetation around the affected plant is threshed in an area of 50 meters (which was previously 100 meters). "The east and the Balearic Islands are the most affected areas.
Their project will initially last 18 months during which they will put
different strains of
Pseudomonas
and
Xylella
to fight in this laboratory,
in vitro
.
"At the moment we are going to do basic science, if we are successful and later we will see how to take it to the field, possibly infiltrating the bacteria into the olive tree or the insect, although that part is still far away," says Bernal.
According to the criteria of The Trust Project
Know more
Science and Health
science
Environment
Environment Last June was the warmest on Earth's surface since 1880
Climate changeCompanies and PP warn of the social impact of the new 'Green Plan' of the EU and ask for balance between economy and environment
Climate crisis No region of the planet is safe from extreme heat
See links of interest
Last News
Gay from Liebana
Work calendar
Home THE WORLD TODAY
Master Investigation Journalism
Tokyo 2020
South Korea - Spain, live
Wang Qiang - Garbiñe Muguruza, live
Sara Sorribes - Fiona Ferro, live
John Millmam - Alejandro Davidovich, live
Iga Swiatek - Paula Badosa, live