Banca de DEFESA: LILIANI OGRODOWCZYK

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : LILIANI OGRODOWCZYK
DATA : 18/07/2019
HORA: 13:30
LOCAL: Embrapa Rondônia
TÍTULO:

Resistance of Coffea canephora clones to Root-knot nematode as a function of environmental stress

PALAVRAS-CHAVES:

Coffee. Enzymes. Defense. Climate changes.

PÁGINAS: 61
GRANDE ÁREA: Outra
ÁREA: Ciências Ambientais
RESUMO:

Brazil is the country with the highest production and export of coffee. However, although well adapted to Brazilian soil and climatic conditions, aspects related to the attack of pathogens cause concern. Among these, Root-knot nematode, which can directly affect coffee productivity, is highlighted. As an alternative for Meloidogyne incognita control, the change of seminal coffees of low technological performance by resistant clonal coffees is used. However, estimates of global climate change scenarios suggest that these may affect the clone resistance, in addition to altering the resourcefulness of the endoparasite in the host. Therefore, the objective of this work was to evaluate the effect of temperature and humidity on two clones of C. canephora, resistant and susceptible to Root-knot nematode. The experiment was conducted at Embrapa Rondônia, in Porto Velho/RO, in randomized blocks, containing 8 treatments and 6 replicates per treatment, being 25 ^oC x 75%, 25 ^oC x 85%, 25 ^oC x 95%, 35 ^oC x 85%  (temperature x humidity), inoculated and non-inoculated plants. Seedlings of clones 723 (susceptible) and 194 (resistant), 4 months old, were planted in a 8 liter substrate vessel (sand and soil, 2:1, respectively). In the treatments with pathogen, a suspension containing 5000 eggs per pot was inoculated and for the control treatment water was used. After 130 days, epidemiological parameter (fresh weight, dry weight, reproduction factor, number of eggs/g root, number of galls/g root, total egg numbers) and activity of enzymes related to the plant defense mechanism such as: Catalase, Phenylalanine Ammonia Liase, Peroxidase and Ascorbate Peroxidase were evaluated. Enzymatic assays followed specific methodologies for each enzyme evaluated, according to the protocol used in our laboratory. Results showed that the weight of fresh and dry matter of both clones reduced after stress at 25 ^oC x 95%, showing a possible reduction of nutrient absorption. Enzymatic assays of leaf extracts resulted in CAT expression only for inoc/ninoc 194 clone at 25 ^oC x 75%, with reduction of POX in clones 194 from 5.0 UA/mgP to 2.5 UA/mgP after 25 ^oC x 95% and absence of APX, evidencing that the clones evaluated in this study have different enzymatic response profiles, probably being related to the genetic characteristics of the materials and/or to the biotic stress (nematode) or the abiotic stress (high humidity conditions).

MEMBROS DA BANCA:
Presidente - 456.271.423-91 - CLEBERSON, DE FREITAS FERNANDES - UFC
Interno - 079.807.827-80 - JOSE ROBERTO VIEIRA JUNIOR - UFV
Externo à Instituição - ROGÉRIO SEBASTIÃO CORRÊA DA COSTA - EMBRAPA