Plett, JM, Plett, KL, Wong-Bajracharya, J, de Freitas Pereira, M, Dutra Costa, M, Kohler, A, Martin, F & Anderson, IC 2020, 'Mycorrhizal effector PaMiSSP10b alters polyamine biosynthesis in Eucalyptus root cells and promotes root colonization.', The New phytologist.View/Download from: Publisher's site
Pathogenic microbes are known to manipulate the defences of their hosts through the production of secreted effector proteins. More recently, mutualistic mycorrhizal fungi have also been described as using these secreted effectors to promote host colonization. Here we characterise a mycorrhiza-induced small secreted effector protein of 10 kDa produced by the ectomycorrhizal fungus Pisolithus albus, PaMiSSP10b. We demonstrate that PaMiSSP10b is secreted from fungal hyphae, enters the cells of its host, Eucalyptus grandis, and interacts with an S-adenosyl methionine decarboxylase (AdoMetDC) in the polyamine pathway. Plant polyamines are regulatory molecules integral to the plant immune system during microbial challenge. Using biochemical and transgenic approaches we show that expression of PaMiSSP10b influences levels of polyamines in the plant roots as it enhances the enzymatic activity of AdoMetDC and increases the biosynthesis of higher polyamines. This ultimately favours the colonization success of P. albus. These results identify a new mechanism by which mutualistic microbes are able to manipulate the host´s enzymatic pathways to favour colonization.
Wong, JW-H & Plett, JM 2019, 'Root renovation: how an improved understanding of basic root biology could inform the development of elite crops that foster sustainable soil health.', Functional plant biology : FPB, vol. 46, no. 7, pp. 597-612.View/Download from: Publisher's site
A major goal in agricultural research is to develop 'elite' crops with stronger, resilient root systems. Within this context, breeding practices have focussed on developing plant varieties that are, primarily, able to withstand pathogen attack and, secondarily, able to maximise plant productivity. Although great strides towards breeding disease-tolerant or -resistant root stocks have been made, this has come at a cost. Emerging studies in certain crop species suggest that domestication of crops, together with soil management practices aimed at improving plant yield, may hinder beneficial soil microbial association or reduce microbial diversity in soil. To achieve more sustainable management of agricultural lands, we must not only shift our soil management practices but also our breeding strategy to include contributions from beneficial microbes. For this latter point, we need to advance our understanding of how plants communicate with, and are able to differentiate between, microbes of different lifestyles. Here, we present a review of the key findings on belowground plant-microbial interactions that have been made over the past decade, with a specific focus on how plants and microbes communicate. We also discuss the currently unresolved questions in this area, and propose plausible ways to use currently available research and integrate fast-emerging '-omics' technologies to tackle these questions. Combining past and developing research will enable the development of new crop varieties that will have new, value-added phenotypes belowground.
Wong, JWH, Lutz, A, Natera, S, Wang, M, Ng, V, Grigoriev, I, Martin, F, Roessner, U, Anderson, IC & Plett, JM 2019, 'The influence of contrasting microbial lifestyles on the pre-symbiotic metabolite responses of Eucalyptus grandis roots', Frontiers in Ecology and Evolution, vol. 7.View/Download from: Publisher's site
© 2019 Wong, Lutz, Natera, Wang, Ng, Grigoriev, Martin, Roessner, Anderson and Plett. Plant roots co-inhabit the soil with a diverse consortium of microbes of which a number attempt to enter symbiosis with the plant. These microbes may be pathogenic, mutualistic, or commensal. Hence, the health and survival of plants is heavily reliant on their ability to perceive different microbial lifestyles and respond appropriately. Emerging research suggests that there is a pivotal role for plant root secondary metabolites in responding to microbial colonization. However, it is largely unknown if plants are able to differentiate between microbes of different lifestyles and respond differently during the earliest stages of pre-symbiosis (i.e., prior to physical contact). In studying plant responses to a range of microbial isolates, we questioned: (1) if individual microbes of different lifestyles and species caused alterations to the plant root metabolome during pre-symbiosis, and (2) if these early metabolite responses correlate with the outcome of the symbiotic interaction in later phases of colonization. We compared the changes of the root tip metabolite profile of the model tree Eucalyptus grandis during pre-symbiosis with two isolates of a pathogenic fungus (Armillaria luteobubalina), one isolate of a pathogenic oomycete (Phytophthora cinnamomi), two isolates of an incompatible mutualistic fungus (Suillus granulatus), and six isolates of a compatible mutualistic fungus (Pisolithus microcarpus). Untargeted metabolite profiling revealed predominantly positive root metabolite responses at the pre-symbiosis stage, prior to any observable phenotypical changes of the root tips. Metabolite responses in the host tissue that were specific to each microbial species were identified. A deeper analysis of the root metabolomic profiles during pre-symbiotic contact with six strains of P. microcarpus showed a connection between these early metabolite responses in the root with later co...
Wong, JW-H, Plett, KL, Natera, SHA, Roessner, U, Anderson, IC & Plett, JM 2019, 'Comparative metabolomics implicates threitol as a fungal signal supporting colonization of Armillaria luteobubalina on eucalypt roots', PLANT CELL AND ENVIRONMENT, vol. 43, no. 2, pp. 374-386.View/Download from: Publisher's site
Li, M-W, Munoz, NB, Wong, C-F, Wong, F-L, Wong, K-S, Wong, JW-H, Qi, X, Li, K-P, Ng, M-S & Lam, H-M 2016, 'QTLs Regulating the Contents of Antioxidants, Phenolics, and Flavonoids in Soybean Seeds Share a Common Genomic Region', FRONTIERS IN PLANT SCIENCE, vol. 7.View/Download from: Publisher's site
Ku, Y-S, Wong, JW-H, Mui, Z, Liu, X, Hui, JH-L, Chan, T-F & Lam, H-M 2015, 'Small RNAs in Plant Responses to Abiotic Stresses: Regulatory Roles and Study Methods', INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, vol. 16, no. 10, pp. 24532-24554.View/Download from: Publisher's site