Movement of the bacterial blight pathogen Erwinia psidii in guava varieties differing in susceptibility
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Erwinia psidii causes bacterial blight of guava, an important disease of this fruit crop in Brazil. Pathogen spread is associated with the movement of infected but asymptomatic propagating plant material. The objective of this study was to compare bacterial movement inside the host tissue and symptom development in two guava varieties commonly grown in Brazil. Guava plants of Pedro Sato and Kumagai varieties were inoculated with strain IBSBF435 by deposition of a bacterial suspension droplet followed by puncture at the axils of the first fully expanded pair of leaves. Disease severity was assessed in the upper third part of the plant and stem fragments were cut at intervals of 1 cm above and below the inoculation point. Samples were collected at 0.5, 1, 2, 4, 6, 8, 10 and 12 days after inoculation. Presence of viable cells of E. psidii at each sampling point was evaluated using Bio-PCR with species-specific primers after a 24 h-enrichment step. Bacterial movement was detected on both directions in both varieties, however a positive correlation between movement and disease severity was observed only for Pedro Sato. Kumagai plants remained symptomless despite the presence of E. psidii above and below the inoculation site.
KeywordsPsidium guajava Bio-PCR Colonization
The authors wish to thank Dr. Abi S. A. Marques for the helpful suggestions and CNPq for the fellowship to M. A. S. V. Ferreira.
- Arriel DAA, Fonseca NR, Guimarães LMS, Hermenegildo PS, Mafia RG, Borges N, de Souza HP, Alfenas AC (2014) Wilt and die-back of Eucalyptus spp. caused by Erwinia psidii in Brazil. Forest Pathology 44:255–265Google Scholar
- Coelho MVS, Mendes AP, Marques ASA (2002) Comunicado técnico 59: Seca dos ponteiros da Goiabeira causada por Erwinia psidii: levantamento e caracterização. Brasília, DFGoogle Scholar
- Horsfall JG, Barratt RW (1945) An improved grading system for measuring plant diseases. Phytopathology 35:655Google Scholar
- Oliveira JR, Ventura JA, Silva I, Costa H (2000) Ocorrência da bacteriose da goiabeira, causada por Erwinia psidii, no estado do Espírito Santo. Fitopatologia Brasileira 25:328Google Scholar
- Rodrigues Neto J, Robbs C, Yamashiro T (1987) A bacterial disease of guava (Psidium guajava) caused by Erwinia psidii sp. nov. Fitopatologia Brasileira 12:345–350Google Scholar
- Romeiro RS, Moraes RMA, Oliveira JR, Couto FAA, Resende ST (1993) Uma enfermidade da Goiabeira de etiologia bacteriana no estado de Minas Gerais, Brasil. In: 26o Congresso Brasileiro de Fitopatologia, Resumos. Aracaju SE, p 283Google Scholar
- Uesugi C, Melo Filho P, Lima M, Moraes C, Tomita C, Café Filho A, Ueno B (2001) Ocorrência de Erwinia psidii em Goiabeira no Distrito Federal. Summa Phytopathologica 27:118Google Scholar