ORCID Profile
0000-0001-9441-7605
Current Organisations
University of Western Australia
,
Murdoch University
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Publisher: Springer Science and Business Media LLC
Date: 22-03-2023
DOI: 10.1007/S11557-023-01878-5
Abstract: Endophytes were investigated for their potential to protect Cinnamomum cassia (cinnamon) from Phytophthora root rot. From healthy cinnamon trees in diseased plantations, 134 bacterial and fungal endophytes were isolated and screened in vitro for their ability to antagonise the root rot pathogens Phytophthora cinnamomi , P. multibullata and P. × vanyenensis . Seventeen endophytes exhibiting high levels of antagonism in vitro (more than 45%) were then tested in a glasshouse study for their ability to reduce the impact of Phytophthora infection in cinnamon seedlings. Trials using cinnamon seeds or seedlings inoculated with an endophyte and then infested with Phytophthora identified three endophytes expressing high levels of disease suppression (based on root damage reduction) and plant growth promotion. These were Penicillium citrinum , Xylaria curta and Clonostachys rosea . These endophytes can potentially be used in the biological control of root rot in cinnamon, but this must be explored further under field conditions.
Publisher: Elsevier BV
Date: 09-2018
Publisher: Springer Science and Business Media LLC
Date: 03-03-2023
DOI: 10.1007/S10658-023-02661-8
Abstract: More Phytophthora species are detected from environmental s les through DNA metabarcoding than are isolated by baiting. We investigated whether bulking soil s les and baiting ~ 300 g s les in standard 1 L tubs resulted in the isolation of fewer Phytophthora and Phytophythium species compared with using 15 – 20 g s les of non-bulked soil in in idual 200 ml tubs. At each of four sites with dying vegetation, 50 soil s les were collected and baited separately in small tubs, followed by plating of lesioned baits over 7 days. The number of Phytophthora species obtained was compared with those obtained from bulking the 50 s les and baiting subs les in large tubs. Half of the asymptomatic baits were plated on day 7 and the remaining were assessed for the presence of Phytophthora using metabarcoding. Root s les with rhizosphere soil from the bulked soil in each site were also assessed using metabarcoding. A higher number of Phytophthora species was recovered from each site from baiting small volumes of non-bulked soil than large volumes of bulked soils. Metabarcoding of the asymptomatic baits revealed species not isolated from lesioned baits. More species were detected from the roots using metabarcoding than were isolated from baits. Metabarcoding did not reveal any species from the rhizosphere soil and roots that were not also detected from metabarcoding of the asymptomatic baits and/or plating. The numbers of Phytopythium species detected using the different methods followed the same trend as for Phytophthora . It was concluded that baiting small s les from across a site in separate small tubs results in the isolation of a higher number of Phytophthora species than the standard technique of baiting large s les of bulked soils, and that this, together with metabarcoding of asymptomatic baits, detects the highest total number of species.
Publisher: Wiley
Date: 08-08-2022
DOI: 10.1111/PPA.13617
Abstract: A study was conducted to determine the pathogens causing root rot, wilt and dieback disease of Cinnamomum cassia (Chinese cinnamon or cassia) in Vietnam, in nurseries and plantations in the Yen Bai, Quang Ninh, Thanh Hoa and Quang Nam provinces, and streams in the Yen Bai province. Pathogens were identified using morphology and internal transcribed spacer (ITS) sequence analysis. The 204 isolates obtained included 125 Phytophthora isolates and 79 from other oomycete genera. There were 112 isolates of P . cinnamomi , four P . heveae , two P . virginiana , three P . multibullata and four P . × vanyenensis . The pathogenicity and virulence of 16 P . cinnamomi , two P . heveae , two P . multibullata and four P . × vanyenensis isolates were assessed using lesion size after under‐bark inoculation of C . cassia stems, and root damage following inoculation of 4‐month‐old C . cassia seedlings. The most virulent isolate from both assessments was a P . cinnamomi from the Quang Nam plantation. Isolates of P . cinnamomi showed a wide range of virulence, with isolates from healthy trees or seedlings showing the lowest virulence. Isolates of P . × vanyenensis , P . multibullata and P . heveae showed moderate or low pathogenicity. This study showed that although P . cinnamomi is the most common pathogen associated with dieback disease in Vietnamese C . cassia plantations, other Phytophthora species may also cause this disease. Knowledge of the presence of these soil‐ and waterborne pathogens will encourage improved soil and water hygiene in nurseries and implement measures to prevent the spread of the pathogens in plantations.
No related grants have been discovered for Jen McComb.