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10/01/2023 A new paper is published in PNAS
The metabolic theory of ecology (MTE) explains why biodiversity increases from the poles towards the equator, a phenomenon first described by Alexander von Humboldt in 1807 with plant and animal species. In recent years, the global distribution patterns of the “invisible” microorganisms have received increasing research attention. Our work is the first attempt to model how bacterial diversity is determined across disparate ecological systems and scales.
The idea is to assume that bacterial metabolic rate is controlled by a theoretical membrane-bound transporter protein whose activity is affected by pH and temperature. The models were experimentally tested using our favourite bacterium Pseudomonas fluorescens SBW25.
03/11/2022 Awarded a Marsden Fund grant ($934,000).
The project is entitled 'Use it or lose it: what determines the regulation mode of a given gene". It aims to experimentally test a gene regulation theory that explains why a bacterium regulates half of its genes positively by an activator and the other half negatively by a repressor. The results will contribute to a predictive theory crucial to understanding the evolutionary consequences of gene regulation modes in natural system and for effective engineering of gene circuits in synthetic biology.
PhD scholarships and research technician positions are available.
06/09/2021 A new paper is accepted for publication in the journal of Environmental Microbiology: "Mutations in surface-sensing receptor WspA lock the Wsp signal transduction system into a constitutively active state".
Here we reports the identification of spontaneous mutations of the Wsp regulatory system, which cause hyper-biofilm production in two Pseudomonas aerugisa strains isolated from crude oil.
This work led to an interesting hypothesis that this naturally occuring regulation loss is an evolutionary dead end, as constitutive hyper-biofilm formation will be at a severe disadvantage in returning to a free-living state. Irreversible genotypic (and phenotypic) change in subpopulations may help bacteria to exploit stressful environments, thus representing a potential altruistic function (Paul Rainey).
05/05/2021. PhD research discoveries a new mode of gene regulation
Naren is very proud that one part of her PhD thesis is published in Nucleic Acids Research, a top journal in the field of molecular biology (impact factor, 17).
Carbon (C) and nitrogen (N) are the two most abundant nutrient elements for life, and their metabolism is tightly controlled in a coupled manner. In bacteria, C/N metabolic balance is maintained by global regulators, which sensor the physiological status of the cell and coordinate the expression of genes for nutrient utilization. However, in this two-author paper, Naren and her PhD supervisor (XX Zhang) surprisingly found that the metabolic process of histidine utilization is governed by a locally acting regulator, which senses nutrient availability and directly modulates activities of the global regulators. This finding is significant as it represents a unique feedback mechanism that involves a local regulator to circumvent the slow responses of the global regulators.
01/04/2021. Our new research shows that loss of the MreB cytoskeletal protein is a crtial evolutionary step leading to the origin of legume-rhizobium symbiosis.
Rhizobia are rod-shaped bacteria that form nitrogen-fixing root nodules on leguminous plants; however, they don’t carry MreB, a key determinant of rod-like cell shape. Here, we introduced an actin-like mreB homolog from a pseudomonad into Mesorhizobium huakuii 7653R (a microsymbiont of Astragalus sinicus L.) and examined the molecular, cellular, and symbiotic phenotypes of the resultant mutant. Our data led to a hypothesis that loss of mreB in the common ancestor of members of Rhizobiales (and subsequent acquisition of ftsZ2) are critical evolutionary steps leading to legume-rhizobial symbiosis.
23/03/2021. International research collaboration enhanced by NZ ambassador’s visit
Earlier this year, Clare Fearnley (New Zealand’s Ambassador to China) and Clinton Watson (NZ Science & Innovation Counsellor in China) visited Huazhong Agricultural University (Wuhan, China) and met our research collaborators over there. Both parties convened at the State Key Laboratories of Agricultural Microbiology, with the postgraduate students being delighted to meet the ambassador as shown in the photo. Three of these students had visited Zhang’s lab at Massey Albany for 6-12 months in 2020, and collaborated on a three-year project jointly funded by both the NZ and Chinese government. This particular project was to develop microbiological techniques to reduce nitrate contamination of water from agricultural soils, a rising concern for both countries.
26/02/2021 New Paper
Great to publish a two-author paper in the prestigious journal of Nucleic Acids Research (in press) and celebrate the latest progress of our long-term research on the molecular mechanisms of histidine catabolism.
18/02/2021 New Paper
A new paper is accepted for publciation in the journal of MPMI: Investigating the involvement of cytoskeletal proteins MreB and FtsZ in the origin of legume-rhizobial symbiosis.
07/09/2020: New Paper
A new manuscript is submitted by Dr. Amber Paulson for a collobrative research with scientists at AgResearch Lincoln: In vivo transcriptome analysis provides insights into host-dependent expression of virulence factors by Yersinia entomophaga MH96, during infection of Galleria mellonella. doi: https://doi.org/10.1101/2020.08.31.276279
29/06/2020 Farewell to Xinyu HU and Shanyu WU
Two PhD students from Huazhong Agricutural Univ (Wuhan, China) visited our lab for six months from the end of November 2019. In additon to research, they went home with a unqiue experience of NZ lockdown from 26 March to 27 April (COVID-19, Alert Level 4). Have a safe trip back home; welcome to come back and explore New Zealand next time.
24/06/2020: New Paper
A new paper is accepted by the journal of BMC Plant Biology: Wenjuan Kang et al. (2020) Plant transcriptome analysis reveals specific molecular interactions between alfalfa and its rhizobial symbionts below the species level.
Wenjuan was a visiting PhD student who had worked in our lab for one year (2018-2019).
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