The Reduced Longitudinal Growth Induced by Overexpression of Is Regulated by Genes Encoding Microtubule-Associated Proteins.

There are three subfamilies of patatin-related phospholipase A (pPLA) group of genes: , , and . Among the four members of (, , , ), the overexpression of three isoforms (, , and ) displayed distinct morphological growth patterns, in which the anisotropic cell expansion was disrupted. Here, the least studied was characterized, and it was found that the overexpression of in Arabidopsis resulted in longitudinally reduced cell expansion patterns, which are consistent with the general phenotype induced by s overexpression. The microtubule-associated protein MAP18 was found to be enriched in a overexpressing line in a previous study. This indicates that factors, such as microtubules and ethylene biosynthesis, are involved in determining the radial cell expansion patterns. Microtubules have long been recognized to possess functional key roles in the processes of plant cells, including cell division, growth, and development, whereas ethylene treatment was reported to induce the reorientation of microtubules. Thus, the possible links between the altered anisotropic cell expansion and microtubules were studied. Our analysis revealed changes in the transcriptional levels of microtubule-associated genes, as well as phospholipase D () genes, upon the overexpression of Overall, our results suggest that the longitudinally reduced cell expansion observed in overexpression is driven by microtubules via transcriptional modulation of the and genes. The altered transcripts of the genes involved in ethylene-biosynthesis in further support the conclusion that the typical phenotype is derived from the link with microtubules.