XVI International Botanical Congess
Hydroxyproline-rich glycoproteins [HRGPs] are cell wall structural proteins that were recently reported to prevent depolymerization of microtubules in protoplasts exposed to 4°C (Akashi et al. 1990), suggesting an interaction between HRGPs and microtubules. The requirement of HRGPs for cortical microtubule organization was investigated in Arabidopsis root cells by inhibiting HRGP hydrxoylation with the proline analog 3,4-dehydro-L-proline (Dhp). One hour after Dhp treatment, cortical microtubules were disorganized in cell walls with shape that did not differ from that of control. Other microtubule arrays were not affected, as determined by immunocytochemistry and confocal laser scanning microscopy. These results suggest that HRGPs are specifically required for cortical microtubule organization. This work was supported in part by the Katherine Esau Post-doctoral Fellowship program, UC Davis.