I am originally from Argentina where I studied Biology and completed my doctorate in Biological Sciences at the University of Córdoba. Currently, I am a postdoc associate at the Burch-Smith lab in the Donald Danforth Plant Science Center in Saint Louis, MO (USA).
During my PhD and a three-year postdoc in Argentina, my research interest has been focused on phytopathology, particularly, the study of viruses that affect cassava crops. I’ve been investigating the epidemiology of the ‘cassava common mosaic disease’ and analyzing the effect on crop yield, in addition to establishing the viral effects on the biology and physiology of source and sink cassava leaves.
Since chloroplasts are one of the main targets of viral infections, I was very curious about the Burch-Smith lab research on Organelle-Nucleus-Plasmodesmata Signaling (ONPS). In my current role, I conduct research related to how signals initiated in chloroplasts have effects on trafficking through plasmodesmata in the working model plant Nicotiana benthamiana . I am also examining geminiviral local and systemic movement in N. benthamiana and cassava plants. By elucidating the form and function of plasmodesmata, we can understand viruses' strategies to improve their movement cell-to-cell and successfully establish the infection.
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Role of chloroplast-initiated intracellular signals in modulating plasmodesmata-mediated intercellular communication in Nicotiana benthamiana
A. A. ZANINI, M. FAZLE AZIM, T. BURCH-SMITH
Donald Danforth Plant Science, 975 N Warson Rd, St. Louis,
MO 63132, USA
Plasmodesmata (PD) are complex membrane-lined nanopores that connect adjacent plant cells facilitating the exchange of essential nutrients, metabolites, and signaling molecules crucial for plant growth, development, and defense. The Organelle-Nucleus-Plasmodesmata Signaling (ONPS) model positions chloroplasts as regulators of PD, influencing nuclear gene expression or signaling directly. According to ONPS, disruption of chloroplast RNA processing, particularly polynucleotide phosphorylase (PNPase), affects intercellular trafficking. Nicotiana benthamiana encodes two PNPase homeologs ( PNPaseA and PNPaseB ). We found that PNPaseA knockdown increases trafficking of free GFP, while simultaneous knockdown of both homeologs decreases intercellular trafficking. This suggests that PNPases regulate chloroplast RNA metabolism, generating retrograde signals that differentially express PD-associated nuclear genes, influencing PD trafficking. Interestingly, our RNAseq analysis of PNPase -silenced plants identified mitochondrial genes and potential pathways controlling intercellular trafficking. These findings contribute to unraveling the ONPS model, shedding light on chloroplast and mitochondria-mediated regulation of each other and PD, and advancing our understanding of plant responses to biotic and abiotic stimuli.