Johannes received his BSc from the Leibniz Universität Hannover (Germany) in Plant Biotechnology in the Fruit Science laboratory of Prof. Moritz Knoche. Inspired by research on water relations of fruit in the Knoche laboratory, Johannes joined the group of Prof. Stephen Tyerman at The University of Adelaide (Australia) with funding through the German Academic Exchange Service. Initially, his work focused on hydraulic properties of grape clusters for which he received his MSc in Agricultural Science. Afterwards, he joined the ARC Centre of Excellence in Plant Energy Biology through the Tyerman laboratory and specialised in molecular plant physiology by studying the role of aquaporins in plant responses to drought for a PhD. He investigated aquaporins, which are molecular channels in plant membranes that provide a gating mechanism for water fluxes and other small molecules, through a combination of gene expression analysis and utilization of transgenic overexpression and CRISPR-Cas9 knockout lines. His work was funded by the highly competitive Adelaide Scholarship International and a Supplementary Scholarship provided by the ARC Centre of Excellence in Plant Energy Biology. In April 2018, Johannes joined the laboratory of Prof. José Dinneny at Stanford University as a Postdoctoral Scholar.

Johannes' research focuses on plant hydraulics from a molecular scale up to whole plants. He is interested on how plants perceive and adapt to changes in the environment in particular related to water. This ranges from developmental decisions to molecular control of water movement, for example through aquaporins.
In the group of Prof. José Dinneny, he is investigating how lateral root branching responds to moisture availability, a phenomenon termed hydropatterning. He uses his expertise to design novel phenotyping systems to characterise lateral root branching across a wide range of diverse corn inbred lines. These technologies enable the use of population genetics approaches to detect genotype-phenotype associations with the aim to understand causal genetic variants and study how phenotypic plasticity is shaped through breeding.

Academic Appointments

  • Basic Life Research Scientist, Biology

Honors & Awards

  • Adelaide Scholarship International, The University of Adelaide (2013)
  • Supplementary Scholarship, ARC Centre of Excellence in Plant Energy Biology (2013)
  • R.N. Robertson Travelling Fellowship, Australian Society of Plant Scientists (2013)
  • ASVO conference scholarship, Australian Society of Viticulture and Oenology (2013)
  • DAAD Scholarship, German Academic Exchange Service (2011)

Boards, Advisory Committees, Professional Organizations

  • Member, Maize Genetics Cooperation (2019 - Present)
  • Member, Australian Society of Plant Scientists (2012 - Present)

Community and International Work

  • Biology Postdoc Committee, Stanford

    Populations Served

    Department of Biology Postdocs


    Bay Area

    Ongoing Project


    Opportunities for Student Involvement


All Publications

  • A Thermoacoustic Imaging System for Noninvasive and Nondestructive Root Phenotyping IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS Singhvi, A., Fitzpatrick, A., Scharwies, J., Dinneny, J. R., Arbabian, A. 2022; 69 (5): 2493-2497
  • Deconstructing the root system of grasses through an exploration of development, anatomy, and function. Plant, cell & environment Viana, W. G., Scharwies, J. D., Dinneny, J. R. 1800


    Well-adapted root systems allow plants to grow under resource-limiting environmental conditions and are important determinants of yield in agricultural systems. Important staple crops such as rice and maize belong to the family of grasses, which develop a complex root system that consists of an embryonic root system that emerges from the seed, and a postembryonic nodal root system that emerges from basal regions of the shoot after germination. While early seedling establishment is dependent on the embryonic root system, the nodal root system, and its associated branches, gains in importance as the plant matures and will ultimately constitute the bulk of below-ground growth. In this review, we aim to give an overview of the different root types that develop in cereal grass root systems, explore the different physiological roles they play by defining their anatomical features, and outline the genetic networks that control their development. Through this deconstructed view of grass root system function, we provide a parts-list of elements that function together in an integrated root system to promote survival and crop productivity. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1111/pce.14270

    View details for PubMedID 35092025

  • Comparing Hydraulics Between Two Grapevine Cultivars Reveals Differences in Stomatal Regulation Under Water Stress and Exogenous ABA Applications FRONTIERS IN PLANT SCIENCE Dayer, S., Scharwies, J. D., Ramesh, S. A., Sullivan, W., Doerflinger, F. C., Pagay, V., Tyerman, S. D. 2020; 11: 705


    Hydraulics of plants that have different strategies of stomatal regulation under water stress are relatively poorly understood. We explore how root and shoot hydraulics, stomatal conductance (gs), leaf and root aquaporin (AQP) expression, and abscisic acid (ABA) concentration in leaf xylem sap ([ABA]xylemsap) may be coordinated under mild water stress and exogenous ABA applications in two Vitis vinifera L. cultivars traditionally classified as near-isohydric (Grenache) and near-anisohydric (Syrah). Under water stress, Grenache exhibited stronger adjustments of plant and root hydraulic conductances and greater stomatal sensitivity to [ABA]xylemsap than Syrah resulting in greater conservation of soil moisture but not necessarily more isohydric behavior. Correlations between leaf (Ψleaf) and predawn (ΨPD) water potentials between cultivars suggested a "hydrodynamic" behavior rather than a particular iso-anisohydric classification. A significant decrease of Ψleaf in well-watered ABA-fed vines supported a role of ABA in the soil-leaf hydraulic pathway to regulate gs. Correlations between leaf and root AQPs expression levels under water deficit could explain the response of leaf (Kleaf) and root (Lpr) hydraulic conductances in both cultivars. Additional studies under a wider range of soil water deficits are required to explore the possible differential regulation of gs and plant hydraulics in different cultivars and experimental conditions.

    View details for DOI 10.3389/fpls.2020.00705

    View details for Web of Science ID 000548384600001

    View details for PubMedID 32636852

    View details for PubMedCentralID PMC7316991

  • Water transport, perception, and response in plants JOURNAL OF PLANT RESEARCH Scharwies, J., Dinneny, J. R. 2019; 132 (3): 311–24
  • Non-Contact Thermoacoustic Sensing and Characterization of Plant Root Traits Singhvi, A., Ma, B., Scharwies, J., Dinneny, J. R., Khuri-Yakub, B. T., Arbabian, A., IEEE IEEE. 2019: 1992–95
  • Association between water and carbon dioxide transport in leaf plasma membranes: assessing the role of aquaporins. Plant, cell & environment Zhao, M., Tan, H., Scharwies, J., Levin, K., Evans, J. R., Tyerman, S. D. 2017; 40 (6): 789-801


    The role of some aquaporins as CO2permeable channels has been controversial. Low CO2permeability of plant membranes has been criticized because of unstirred layers and other limitations. Here we measured both water and CO2permeability (Pos, PCO2) using stopped flow on plasma membrane vesicles (pmv) isolated from Pisum sativum (pea) and Arabidopsis thaliana leaves. We excluded the chemical limitation of carbonic anhydrase (CA) in the vesicle acidification technique for PCO2using different temperatures and CA concentrations. Unstirred layers were excluded based on small vesicle size and the positive correlation between vesicle diameter and PCO2. We observed high aquaporin activity (Pos0.06 to 0.22 cm s-1) for pea pmv based on all the criteria for their function using inhibitors and temperature dependence. Inhibitors of Posdid not alter PCO2. PCO2ranged from 0.001 to 0.012 cm s-1(mean 0.0079 + 0.0007 cm s-1) with activation energy of 30.2 kJ mol-1. Intrinsic variation between pmv batches from normally grown or stressed plants revealed a weak (R2 = 0.27) positive linear correlation between Posand PCO2. Despite the low PCO2, aquaporins may facilitate CO2transport across plasma membranes, but probably via a different pathway than for water.

    View details for DOI 10.1111/pce.12830

    View details for PubMedID 27620674

  • Comparison of isohydric and anisohydric Vitis vinifera L. cultivars reveals a fine balance between hydraulic resistances, driving forces and transpiration in ripening berries FUNCTIONAL PLANT BIOLOGY Scharwies, J. D., Tyerman, S. D. 2017; 44 (3): 324-338

    View details for DOI 10.1071/FP16010

    View details for Web of Science ID 000395563300005

  • Russeting and Relative Growth Rate Are Positively Related in 'Conference' and 'Condo' Pear HORTSCIENCE Scharwies, J. D., Grimm, E., Knoche, M. 2014; 49 (6): 746-749