Effects of leaf position, surface, and entry sites on Quambalaria eucalypti infection in eucalypt

Abstract

The objectives of this study were to determine the effects of leaf position, surface, and the need for entry sites, such as wounds, other pathogen lesions or natural openings, to promote infection of Quambalaria eucalypti in Eucalyptus spp. We carried out a series of artificial inoculations in wounded and unwounded leaves from seedlings of Eucalyptus globulus and two hybrid clones (UFV-100 �� E. grandis x E. urophylla and UFV-101 -E. saligna x E. maidenii). E. globulus was more susceptible to infection than clones UFV-100 and UFV-101. Artificial wounds greatly favored pathogen penetration. However, old lesions caused by Cylindrocladium pteridis and Puccinia psidii did not provide infection sites for Q. eucalypti. Differences in fungal spore germination and leaf surface colonization were not observed between expanding and fully expanded leaves. Q. eucalypti penetrated through the wounded leaves and we didn't observe direct penetration thought the epidermis. Stomata neither attracted nor repelled germ tube and somatic hyphae. Young expanding leaves were more susceptible to Q. eucalypti infection than fully expanded leaves located in the upper third of the plant. Infection took place preferentially on the abaxial leaf surface. Keywords: Eucalyptus, host-pathogen interaction, inoculation protocol, leaf spot. RESUMO Efeito da posição e superfície foliar sobre a infecção de Quambalaria eucalypti e determinação sítios de entrada em eucaliptoObjetivou-se, neste estudo, determinar os efeitos da posição da folha, superfície foliar e os sítios de entrada, assim como ferimentos, lesões de outros patógenos ou aberturas naturais sobre a infecção de Quambalaria eucalypti em Eucalyptus spp. Para isso, realizaram-se inoculações artificiais em folhas de mudas seminais de Eucalyptus globulus e dois clones híbridos de Eucalyptus (UFV-100 �� E. grandis x E. urophylla e UFV-101 -E. saligna x E. maidenii). E. globulus foi mais suscetível à infecção que os clones UFV-100 e UFV-101. Os ferimentos artificiais favoreceram a penetração do patógeno. Entretanto, lesões velhas causadas por Cylindrocladium pteridis e Puccinia psidii não foram sítios de entrada de Q. eucalypti. Não foram observadas diferenças na germinação de esporos e colonização entre folhas em expansão e completamente expandidas. Q. eucalypti penetrou em folhas com ferimentos. Contudo não foi possível observar a penetração direta através da epiderme. Folhas jovens foram mais suscetíveis à infecção de Q. eucalypti que folhas completamente expandidas no terço superior da planta. A infecção ocorreu preferencialmente na superfície abaxial da folha. Palavras-chave: Eucalyptus, interação patógeno-hospedeiro, protocolo de inoculação, mancha foliar.

Quambalaria eucalypti found on Eucalyptus in Indonesia

“…This is an interesting result as the pathogen has previously been shown to easily infect young and unwounded leaf and shoot tissue (Pegg, Webb, et al, 2009; Wingfield et al, 1993). In contrast, our results are similar to those of Mafia et al (2009) who showed that wounds favoured infection by Q. eucalypti . These results are intriguing given the fact this pathogen is clearly able to infect leaves via the stomata (Pegg, Webb, et al, 2009) and thus typical of a primary pathogen.…”

“…An initial inoculation trial was conducted using an E . pellita clone (clone ECL04) known to be susceptible to infection in the nursery, following the methods described by Mafia et al (2009) and Bragança et al (2016) with some modifications. Eight‐week‐old plants were used in this test that included nine different isolates chosen to represent the range of collection sites (Table 1).…”

Infection Process of Botrytis cinerea on Eucalypt Leaves

“…psidii ‐eucalypt (Souza ), Quambalaria eucalypti ‐eucalypt (Mafia et al. ), Peronospora tabacina ‐ tobacco (Reuveni et al. ) mainly infect new leaves.…”

Responses of Phyllosphere Microbial Population of Some Common Road Trees In Relation To Dust Deposition – A Case Study in Kolkata, India

“…Ficus Benghalensishad greater efficiency of dust adsorption so there are chances to use it as passive air pollution monitor. Mafia et al [30] was observed the occurrence of fungal community on the lower surface of leaf of Eucalyptus spp. They also observed the growth of fungal colony at close to leaf stomata.…”