Plant Stress Resilience Lab

We are developing novel multiscale methods for quantitative analyses of cell walls at tissue-, cellular- and sub-cellular scales. As a proof-of-concept, we evaluated suberin accumulation in response to water limitation using traditional and novel chemical imaging approaches. Our multi-disciplinary approach to studying cell walls will identify the role of different cell wall components in regulating plant growth under normal and stressful environments.

_{Fluorol yellow staining showing increased exodermal suberin accumulation in water-stressed (WS) maize primary roots compared to well-watered (WW) control. The transverse sections were obtained from 30-40 mm of root tip regions in both treatments.}

Primary cell walls of grasses contain ferulates, phenolic compounds, that cross-link wall polysaccharides and potentially cause cell wall stiffening. However, it is not known if ferulate accumulation impacts growth in response to environmental cues. Currently, we are testing the hypothesis that accumulation of cell wall-bound ferulates under water stress is causally related to reduced growth responses of maize primary roots. Correlating with their region-specific growth responses, the apical and basal regions of water-stressed roots showed decreased and increased levels of wall-bound ferulates respectively, compared to well-watered roots. Enzymatic removal of wall-bound ferulates with the enzyme feruloyl esterase enhanced cell wall extensibility in basal regions of well-watered and water-stressed roots. We are exploring the implications of these findings with computational modeling and genetic mutant analyses to understand how ferulates regulate growth of maize primary roots under water limitation.

_{Feruloyl esterase (FE) treatment reduces ferulate fluorescence in transverse sections of roots obtained from the basal region (3-7 mm from root tip) of water-stressed (WS) roots.}

We are interested in assessing sugar movement in plants under normal and stressful environments. Using a novel in vivo assay, we showed the spatial variability in glucose exudation in roots of different plant species (Voothuluru et al., 2018). We plan to explore the regulation of spatial variability of glucose exudation under normal and water limited conditions, since these responses have major implications for root-rhizosphere interactions. We are also interested in exploring the regulation of sugar movement from vegetative to reproductive structures under water limitation.

_{In vivo glucose localization in maize ovaries showing maximum glucose intensity in pericarp tissues. The ovary section was placed on the gel containing assay constituents shows tissue-specific glucose accumulation (after 120 s of exposure).}