Characterization of allelic variants of an orthologous Tomato-Ve1 sequence and phenotypic responses to Verticillium-wilt caused by Verticillium dahliae (Kleb) in a Sunflower Association Mapping Population

MONTECCHIA JF; FILIPPI C.; LIA V.V.; QUIROZ F.; PANIEGO N.; HEINZ R.A.

Foz de Iguazu

Congreso; 11th International Plant Molecular Biology Congress; 2015

Sunflower Verticillium Wilt (SVW), caused by the soil-borne fungal pathogen Verticillium dahliae (Vd), is one of the most important diseases within the south-eastern region of Buenos Aires, nowadays the main sunflower-productive area in Argentina. This fungal pathogen has a broad host-range among dicotyledonous species of agronomic interest. A single locus conferring resistance against Verticillium wilt has been reported in tomato. This locus, named Ve1, encodes for a cell surface receptor protein that belongs to the extracellular Leu-rich-repeat receptor-likeprotein class of disease resistance proteins. Ve1 has been proven to recognize the Verticilliumrace1-Ave1 effector and trigger the defense response rendering resistance. In Lettuce (Asteraceae) an Expressed Sequence Tag (EST) marker with sequence similarity to Ve1 was mapped in a coincident location to Vr1, the single dominant resistance gene of Lettuce against Vd. SVW resistance is considered polygenic and different resistance sources were reported. An orthologoussequence for Ve1 was found by our group in a sunflower EST data base through an in-silicosequence-global alignment strategy. We had designed a specific-primer-pair for this sequence, in order to amplify and sequence the target gene on the 137 sunflower inbred lines of the INTA association mapping population (IAMP). Two field-trials were performed at the EEA-INTA-Balcarce, in plots harboring high Vd-inoculum titers, under standard field-growing conditions. SVW-Intensity (Incidence x Severity) was measured to asses IAMP-lines resistance. The SVW-symptoms wereestimated weekly from R3 to R7-phenological-stages. Association of the allelic variants found by computational-sequence-analysis with the phenotypic responses to SVW is further discussed in this work.