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A turanose‐insensitive mutant suggests a role for WOX5 in auxin homeostasis in Arabidopsis thaliana
Author(s) -
Gonzali Silvia,
Novi Giacomo,
Loreti Elena,
Paolicchi Fabio,
Poggi Alessandra,
Alpi Amedeo,
Perata Pierdomenico
Publication year - 2005
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2005.02555.x
Subject(s) - meristem , auxin , arabidopsis , mutant , arabidopsis thaliana , polar auxin transport , microbiology and biotechnology , wild type , biology , chemistry , biochemistry , gene
Summary Sugars acting as signalling molecules regulate many developmental processes in plants, including lateral and adventitious root production. Turanose, a non‐metabolizable sucrose analogue, profoundly affects the growth pattern of Arabidopsis seedlings. Turanose‐treated seedlings are characterized by a very short primary root and a short hypocotyl showing the production of adventitious roots. A turanose‐insensitive ( tin ) mutant was identified and characterized. Because of a T‐DNA insertion and a chromosomal translocation, tin expresses a chimeric form of WOX5 , a gene known to be expressed in the root quiescent centre. The tin mutation can be complemented by overexpression of WOX5 , suggesting it is a loss‐of‐function mutant. We found that WOX5 is both turanose‐ and auxin‐inducible. Moreover, turanose insensitivity is associated with altered auxin homeostasis, as demonstrated by the constitutive activation of indole acetic acid (IAA) conjugation and SUPERROOT2 expression in tin . On the basis of turanose effects on wild‐type seedlings and the tin molecular and hormonal phenotype, we propose a role for WOX5 in the root apical meristem as a negative trigger of IAA homeostatic mechanisms allowing the maintenance of a restricted area of auxin maximum, which is required for a correct root‐formation pattern.