Method for obtaining a plant with a lasting resistance to a pathogen

Abstract

Corresponding results were obtained with A method for obtaining a plant, in particular a cultivated lettuce plant ( L. sativa ), with a lasting resistance to a pathogen, in particular Bremia lactucae , comprising of providing one or more specific DNA markers linked to one or more resistance genes, determining the presence of one or more resistance genes in a plant using these DNA markers, subsequently crossing a first plant comprising one or more resistance genes with a second plant comprising one or more resistance genes, and selecting from the progeny a plant in which one or more resistance genes are present by using the DNA markers. The invention further relates to the plants obtained with this method, seeds and progeny of these plants, as well as progeny thereof.

1 . A lettuce plant having a lasting resistance to  Bremia lactucae , wherein said lettuce plant has at least two broad-spectrum Dm-resistance genes, wherein said Dm-resistance genes are selected from the group consisting of Dm-resistance gene A represented by an accession number CGN9365 and Dm-resistance gene B represented by an accession number CGN4683. 
     
     
         2 . The lettuce plant of  claim 1 , wherein said lettuce plant having at least two broad-spectrum Dm-resistance genes is produced from a cultivated lettuce plant ( L. sativa ) crossed with a wild lettuce plant having a different at least two or more broad-spectrum Dm-resistance genes and further wherein said wild lettuce plant is represented by an accession number selected from the group consisting of CGN9365 and CGN4683. 
     
     
         3 . The cultivated lettuce plant of  claim 2 , wherein said cultivated lettuce plant is selected from the group consisting of head lettuce including  L. sativa Lineaus capitata ; leaf lettuce for picking including  L. sativa Lineaus acephala ; cos lettuce including  L. sativa Lineaus romana ; leaf lettuce for cutting including  L. sativa Lineaus secalina  and asparagus lettuce including  L. sativa Lineaus angustana.    
     
     
         4 . The cultivated lettuce plant of  claim 2 , wherein said cultivated lettuce plant is selected from the group consisting of iceberg lettuce, batavia lettuce and butterhead lettuce. 
     
     
         5 . The cultivated lettuce plant of  claim 2 , wherein said cultivated lettuce plant is selected from the group consisting of curly leaf lettuce and stem lettuce. 
     
     
         6 . The lettuce plant of  claim 2 , wherein said plant comprises two or more DNA-sequences selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5 and SEQ ID NO: 6. 
     
     
         7 . A lettuce seed having a lasting resistance to  Bremia lactucae , wherein said lettuce seed has at least two broad-spectrum Dm-resistance genes, wherein said Dm-resistance genes are selected from the group consisting of Dm-resistance gene A represented by an accession number CGN9365 and Dm-resistance gene B represented by an accession number CGN4683. 
     
     
         8 . A lettuce plant produced by growing the seed of  claim 7 . 
     
     
         9 . Pollen of the plant of  claim 8 . 
     
     
         10 . An ovule of the plant of  claim 8 . 
     
     
         11 . A tissue culture comprising regenerable cells of the plant of  claim 8 . 
     
     
         12 . A lettuce plant regenerated from said tissue culture of  claim 11 . 
     
     
         13 . The lettuce plant of  claim 12 , wherein said plant comprises two or more DNA-sequences selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5 and SEQ ID NO: 6. 
     
     
         14 . A method for obtaining a cultivated lettuce plant ( L. sativa ) with a lasting resistance to  Bremia lactucae , comprising crossing a cultivated lettuce plant with another cultivated lettuce plant, or a wild lettuce plant, comprising at least two or more broad-spectrum Dm-resistance genes, and selecting from the progeny thereof a cultivated lettuce plant with two or more broad-spectrum Dm-resistance genes, wherein said Dm-resistance genes are selected from the group consisting of Dm-resistance gene A represented by an accession number CGN9365 and Dm-resistance gene B represented by an accession number CGN4683. 
     
     
         15 . The method of  claim 14 , wherein said broad-spectrum Dm-resistance genes are located in different linking groups. 
     
     
         16 . The method of  claim 14 , wherein said wild lettuce plant is chosen from the group consisting of  L. serriola, L. virosa, L. saligna, L. altaica, L. aculeata, L. homblei, L. indica, L. tenerrima, L. squarrosa, L. viminea, L. augustana, L. quercina , and  L. cacadensis.    
     
     
         17 . The method of  claim 14 , wherein said wild lettuce plant is  L. serriola.    
     
     
         18 . The method of  claim 14 , wherein said wild lettuce plant is  L. virosa.    
     
     
         19 . The method of  claim 14 , wherein said cultivated lettuce plant is chosen from the group consisting of head lettuce including  L. sativa Lineaus capitata ; leaf lettuce for picking including  L. sativa Lineaus acephala ; cos lettuce including  L. sativa Lineaus romana ; leaf lettuce for cutting including  L. sativa Lineaus secalina  and asparagus lettuce including  L. sativa Lineaus angustana.    
     
     
         20 . The method of  claim 14 , wherein said progeny comprises two or more DNA-sequences selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5 and SEQ ID NO: 6.