Addressing crops relevant to CA agriculture such as Pistachio, Almond and Olives, we are investigating mechanisms of stress response and fruit development.

Characterization of root plasticity during salinity stress response

Because root system is the first layer of salinity response, we use fluorescence microscopy-based methods for sodium detection and anatomical characterization of pistachio and almond rootstocks. Analyzing root response across a developmental gradient, we showed that sodium sequestration in the vacuole, along with cell wall reinforcement of cellular barriers (endodermis and exodermis) in roots, are important contributing factors to salinity tolerance in pistachio and almond rootstocks. Building on
this effort we are exploring the combination of salinity and drought in pistachio. These foundational studies reveal mechanisms of salinity tolerance from cellular and structural perspectives across a root developmental gradient, which are useful insights for future stress response screens.

Pistachio fruit development

We examine mechanisms that control pistachio development including hull and shell split and kernel discoloration, all of which are impacting its commercial value. We perform anatomical and morphological studies along with gene expression RNAseq analysis at a spatiotemporal level during fruit development across different genotypes and growing seasons. Our studies indicate that shell split is associated with cell shape and cell wall composition at the suture size, while the width of the kernel enhances shell split rates.

Olive fruit abscission

We are investigating the effect of ethylene precursors in table olive fruit and leaf abscission development. Our studies are in close collaboration with B Blanco, Pat, J Brown, L Ferguson, G Marino, G Monroe, R Michelmore ( UC Davis, Plant Sciences and Holman (LBNL) J Richardson (SSRL).