Diseases

Lettuce tissue necrosis

Lactuca sativa L.

Tissue necrosis in lettuce is a symptom complex caused by infectious pathogens (fungi, viruses, bacteria) as well as physiological stresses or genetic incompatibility during hybridization.

In the reference 424 varieties crop Lettuce, where this is mentioned in the description.

Infectious causes of necrosis include Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. lactucae (accompanied by vascular and root necrosis), viral infections such as LNYV or INSV, and bacterial leaf spot caused by Xanthomonas vitians. Root rots, provoked by Pythium spp., lead to secondary tissue necrosis due to disruption of plant nutrition.

Physiological necrosis develops independently of pathogens under the influence of high temperatures, water deficit, and mechanical damage, leading to the death of parenchyma cells. Genetically determined necrosis can also occur as a result of an autoimmune reaction due to the incompatibility of NLR gene alleles in seedlings.

Resistance to necrotic lesions caused by pathogens is genetically controlled: monogenic resistance has been described for protection against Fusarium oxysporum, and for protection against the INSV virus, quantitative trait loci (QTLs) have been identified, such as qINSV2.1, localized on the second chromosome.

General information about the subject — on the page Tissue necrosis.

Sources8

Varieties of Lettuce mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.