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Projecte llegit

Títol: Gestió de Meloidogyne en cultius hortícoles mitjançant resistència induïda per part de mírids

Estudiant que ha llegit aquest projecte:

Tutor/a o Cotutor/a: GINÉ BLASCO, ARIADNA

Departament: DEAB

Títol: Gestió de Meloidogyne en cultius hortícoles mitjançant resistència induïda per part de mírids

Data inici oferta: 03-02-2023      Data finalització oferta: 03-10-2023

Estudis d'assignació del projecte:
    GR ENG CIEN AGRONOM

Lloc de realització:
EEABB

Segon tutor/a (UPC): SORRIBAS ROYO, FRANCISCO JAVIER

Paraules clau:
Hortalísses, Macrolophus, Nematode fitoparàsit, Meloidogyne spp.

Descripció del contingut i pla d'activitats:
A Catalunya, el nematode fitoparàsit causant de les majors
pèrdues de producció en cultius hortícoles és Meloidogyne spp. La
resistència genètica és altament eficaç per al control dels
nematodes i es pot utilitzar a través de conreus o portaempelts
que porten gen(s) R. Malauradament, hi ha pocs gens de
resistència comercials disponibles en cultius d'hortalisses. Un
altre tipus de resistència és la resistència induïda de les
plantes a resposta a estímuls d'agents biòtics i/o abiòtics. Hi
ha evidències de l'activació dels mecanismes de defensa del
tomàquet contra Meloidogyne per part de microosganismes, però se
sap poc sobre la capacitat dels mírids. L'objectiu d'aquest TFG
és determinar la capacitat d¿inducció de resistència de dos
mírids, Macrolophus pygmaeus i Nesidiocoris tenuis , en front a
Meloidogyne spp. Per a dur-lo a terme, es realitzarà un
experiment en testos i en cambra climàtica on s¿avaluarà
l¿efecte de la picada prèvia a la inoculació dels nematodes dels
dos mírids en solanàcies (tomàquet, pebrot i albergínia),
cucurbitàcies (cogombre, carbassó i síndria), compostes (enciam),
quenopodiàcies (bledes) i lleguminoses (mongetes) en la infecció
i reproducció del nematode

Overview (resum en anglès): The nematode genus Meloidogyne has an extensive range of host plants and constitutes the
main nematological problem in horticultural crops worldwide. Yield losses caused by
Meloidogyne spp. have been estimated 15% to 60% in Mediterranean countries. Traditionally,
chemical disinfectants such as methyl bromide were used systemically to reduce soil
pathogens until their prohibition under Regulation (EC) No 1005/2009 of 16 September. Faced
with this, the need to find alternative management is exacerbated and emphasis is placed on
biofumigation, solarization, research into antagonistic organisms, the use of resistant
rootstocks and the inducement of resistance from the crop itself.
It has been documented that the repeated use of resistant Mi-1.2 rootstocks creates virulent
populations, thus overcoming initial resistance. Therefore, plant-induced resistance does not
compromise the environment and could play an important role in alternating management
strategies against phytoparasitic nematodes. The presence of zoophytophag biological control
agents such as the family Miridae has been shown to induce both direct and indirect resistance
to beneficial plant preventing pathogenic microorganisms as well as phytoparasitic nematodes.
The aim of the work is to verify whether Macrolophus pygmaeus activate induced tomato
plant resistance either susceptible or resistant, thus decreasing Meloidogyne spp. infection
and/or reproduction capacity. We had tomato plants for 48 hours exposed to 15 individuals of
M. pygmaeus per plant with the help of a mesh, forcing the insect to feed on the plant's aerial
tissue. We had 12 samples per treatment, being the control those that had no inducement of
M. pygmaeus and having resistant plant, with the Mi-1.2 gene, of the Caramba variety and a
susceptible plants of the Roma variety. We performed the same treatments for the Gadir
population (Meloidogyne arenaria, M. hapla and M. javanica) and for the Agropolis population
(M. incognita) both virulent, having a repetition of the experiment due to validate it. The
inoculation was made on the same day that the M. pygmaeus were withdrawn, with second-stage juveniles at a ratio of 1 juvenile/ml. Tomatoes were held in a 26-degree controlled
temperature camera and 16:8h photoperiod for 45 days with 200mL flowerpots.
The results indicate that tomatoes previously exposed to M. pygmaeus have less infection of
the nematodes of the genus Meloidogyne in the case of susceptible plants, but the difference
were not significant in the case of resistant plants. Therefore, with an aim to verify the
previous results and resolve what happens in resistant plants, we performed the same
experiment, with the same virulent Agropolis population, with Maxifort resistant rootstock
tomatoes, Cornabel commercial tomatoes and Maxifort- Cornabel grafted tomatoes. The
results of the second experiment showed significant differences in infection in susceptible
plant in the first experiment but another extension of the experiment would have to be
performed to check what happens in the case of resistant plant and grafted plant as the results
were inconsistent. However, is concluded that the phytophage effect of M. pygmaeus on
susceptible tomato beans before inoculation of a virulent population of Meloidogyne spp. It
acts as an inducer to the defenses of tomato plants and therefore nematode infection is minor.
The interactions between zoophytophagous insects and nematodes is a poorly explored line of
research, with many unknowns to be solved.

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