Partial resistance to myrtle rust and photosynthetic responses on 'Suprema' guava plants infected by Austropuccinia psidii

Autor(es)

Sales, Lucas Santos ; Goncalves, Manoel Penachio ; Appezzato-da-Gloria, Beatriz ; Amorim, Lilian

• Tipo de documento: Artigo Científico
• Fonte: ROPICAL PLANT PATHOLOG; v. N/A, p. 13-pg., 2023-07-18.

Resumo

Brazil is the largest red-fleshed guava producer in the world. Cultivar 'Paluma', which is cultivated by most of guava growers in Brazil, is susceptible to myrtle rust (Austropuccinia psidii). In recent years, the area with other guava cultivars has been expanded in order to diversify the production. 'Suprema' red-fleshed guava cultivar is a promising genotype, because of its high yield. However, there is a lack of information about its interaction with A. psidii and the damage caused by the disease in that cultivar. The objectives of this study were to characterise the monocyclic components of myrtle rust and photosynthetic damage caused by this disease in Suprema. Young leaves of Suprema and Paluma potted plants were inoculated with A. psidii urediniospore suspensions and kept under favourable conditions for disease development. The A. psidii pre-penetration process and disease monocyclic components were evaluated in both cultivars. Hydrogen peroxide (H2O2) production was evaluated in Suprema. Additionally, young leaves of Suprema were inoculated with varying concentrations of A. psidii inoculum, and net photosynthesis was correlated with rust severity. The percentages of urediniospore germination and appressoria formation of A. psidii were similar in both cultivars and rust resistance in Suprema was unrelated to H2O2 production shortly after pathogen infection. However, lesion density, lesion size, number of urediniospores lesion(-1), and disease severity were significantly lower in Suprema compared to Paluma. A severe reduction in net photosynthesis was observed in Suprema inoculated plants. Although the reduction on photosynthesis is proportionally higher than the diseased area in Suprema, it is not expected guava rust will be a problem as inoculum production is very low in Suprema leaves. Suprema features high partial rust resistance and is an excellent option for guava producers. (AU)

• Processo FAPESP: 19/13191-5 - Componentes epidemiológicos, caracterização de danos e controle de ferrugens tropicais e temperadas em cenário de mudança climática global
• Beneficiário: Marcel Bellato Spósito
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 20/07746-1 - Suscetibilidade de cultivares de goiabeira a Austropuccinia psidii
• Beneficiário: Lucas Santos Sales
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica