title: Different effects of aluminum on the actin cytoskeleton and brefeldin A-sensitive vesicle recycling in root apex cells of two maize varieties differing in root elongation rate and aluminum tolerance.
abstract: A relationship between aluminum (Al) toxicity, endocytosis, endosomes and vesicle recycling in the root transition zone has recently been demonstrated. Here the importance of filamentous actin (F-actin)-based vesicle trafficking for Al tolerance has been investigating in maize varieties differing in their Al sensitivities. More Al was internalized into root tip cells of the Al-sensitive variety 16x36 than in the Al-tolerant variety Cateto. The actin cytoskeleton and vesicle trafficking were primary targets for Al toxicity in the root tips of the sensitive variety. Visualization of boron-cross-linked rhamnogalacturonan II (RGII)-containing brefeldin A (BFA) compartments revealed that Al inhibited the formation of these compartments, especially in variety 16x36. The time sequence of Al effects on pectin recycling matches the growth effects of Al in this sensitive variety. These results support the hypothesis that Al binding to pectin-rich cell walls can contribute to reversible inhibition of root elongation. Al-induced alterations on F-actin were most evident in the central part of the transition zone of Al-sensitive 16x36, where Al was localized inside the nucleoli. In relation to this observation, a role for symplastic Al in both irreversible growth inhibition and amelioration of BFA-induced inhibition of root elongation is discussed.
authors.affiliation: Institut für Zelluläre und Molekuläre Botanik, Universität Bonn, Kirschallee 1, D-53115 Bonn, Germany.
authors.forename: Montse
authors.initials: M
authors.lastname: Amenós
authors.forename: Isabel
authors.initials: I
authors.lastname: Corrales
authors.forename: Charlotte
authors.initials: C
authors.lastname: Poschenrieder
authors.forename: Peter
authors.initials: P
authors.lastname: Illés
authors.forename: Frantisek
authors.initials: F
authors.lastname: Baluska
authors.forename: Juan
authors.initials: J
authors.lastname: Barceló
mesh_terms: D000199:Actins / Q000378:metabolism; D000535:Aluminum / Q000378:metabolism / Q000633:toxicity*; D020126:Brefeldin A / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D010368:Pectins / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000199:Actins; C042492:rhamnogalacturonan II; D020126:Brefeldin A; D010368:Pectins; D000535:Aluminum