Magic™ Anti-Arabidopsis thaliana CESA1 (Phospho S167) polyclonal antibody

Quantitative expression analysis of three cellulose synthases/subunits encoding genes (cesAl, cesAlb, and cesA2) during three fibre development stages [3, 15 and 35 days post anthesis (dpa)] in Gossypium arboreum, G. anomalum, and G. hirsutum was undertaken. Exceptionally high expression was observed in G. hirsutum at 15 dpa stage for cesAl and cesA2 (6.5 and 7.7 magnitude increase over (3 tubulin) genes, which might be responsible for longer fibre in G. hirsutum. Moderately high expression of cesAl gene was recorded in G. arboreum (at 15 dpa), and in G. anomalum (at 3 and 15 dpa). However cesAl gene expression was negligible in G. arboreum, and G. hirsutum at 3 dpa and in all three species at 35 dpa. Strong increase in expression levels of cesAlb gene (6.4 magnitude increase over (3 tubulin) was observed in G. arboreum at 15 dpa stage. Expression levels of cesAlb gene were moderate in G. hirsutum (at 3 and 15 dpa) and in G. anomalum (at 15 dpa); while its expression was low to negligible in rest of the samples. The cesA2 gene expressed at moderate to low levels at 3 dpa in G. anomalum and G. hirsutum; at 15 dpa in G. arboreum and G. anomalum; and at 35 dpa in all three species. During fibre initiation, expression of all three cellulose synthase genes was negligible in G. arboreum. In fuzzy fibred G. anomalum expression of all three ces genes was low (nil for cesAl at 3 dpa) at all the stages. These results indicate that different cellulose synthase genes, cesA1 and cesA2 (in G. hirsutum) and cesAlb (in G. arboreum) play a predominant role in fibre development.

Cellulose synthesis at the plasma membrane is a critical process in plant growth and development. The displacement of cellulose synthase complexes (CSCs) by the rigid cellulose polymers they produce is a measure of enzyme activity. Connections between cortical microtubules and CSCs have been identified but it remains unclear how these affect CSC displacement speed. In this study, we applied a high throughput automated particle tracking method using near-total internal reflection fluorescence microscopy to measure the speed of CSCs. We found CSC speeds did not vary according to their proximity to microtubules, and that inhibiting microtubule polymerization could have opposite effects on CSC speed, depending on the nature of inhibition. While CSC speed increased in the temperature-sensitive mor1-1 mutant, it decreased after treatment with the drug oryzalin. Moreover, introducing the mor1-1 mutation into the CesA1 mutant any1 increased CSC speed, suggesting that microtubule dynamics affect CSC speed by a mechanism other than Cellulose Synthase A (CesA) catalytic activity. CSC speed varied widely in a range of mutants with reduced growth anisotropy, indicating that the relationship between CSC speed and anisotropy is complex. We conclude that microtubules affect CSC speed by finely tuned mechanisms that are independent of their physical association with CSCs.