Nuclear localization and interaction of RolB with plant 14‐3‐3 proteins correlates with induction of adventitious roots by the oncogene rolB

Abstract

SummaryThe rooting-locus gene B (rolB) on the T-DNA of the root-inducing (Ri) plasmid in Agrobacterium rhizogenes is responsible for the induction of transformed adventitious roots, although the root induction mechanism is unknown. We report here that the RolB protein of pRi1724 (1724RolB) is associated with Nicotiana tabacum 14-3-3-like protein vII (Nt14-3-3 vII) in tobacco bright yellow (BY)-2 cells. Nt14-3-3 vII directly interacts with 1724RolB protein. Green¯uorescent protein (GFP)-fused 1724RolB is localized to the nucleus. GFP-fused mutant 1724RolB proteins having a deletion or amino acid substitution are unable to interact with Nt14-3-3 vII and also show impaired nuclear localization. Moreover, these 1724RolB mutants show decreased capacity for adventitious root induction. These results suggest that adventitious root induction by 1724RolB protein correlates with its interaction with Nt14-3-3 vII and the nuclear localization of 1724RolB protein.

Phosphorylation of HopQ1, a Type III Effector from Pseudomonas syringae, Creates a Binding Site for Host 14-3-3 Proteins

“…Exoenzyme S, an ADP-ribosyl-transferase toxin secreted by the TTSS of Pseudomonas aeruginosa, becomes active upon interaction with host 14-3-3 proteins (Ottmann et al, 2007). The nuclear accumulation of RolB, a bacterial oncoprotein involved in the pathogenesis of Agrobacterium rhizogenes, depends upon binding to a specific isoform of 14-3-3 (Moriuchi et al, 2004). Based on in silico predictions, HopQ1 is classified as a nucleoside hydrolase; however, this activity could not be detected in the recombinant protein produced in E. coli.…”

TherolBGene Suppresses Reactive Oxygen Species in Transformed Plant Cells through the Sustained Activation of Antioxidant Defense

“…The localization of these proteins in plant cells is also different. HopAO1 is localized to the soluble fraction of protein extracts (Underwood et al, 2007), whereas RolB is localized in the plasma membrane (Filippini et al, 1996) or in the nucleus (Moriuchi et al, 2004). Therefore, these proteins have probably evolved independently.…”

“…The mechanism by which the RolB oncoprotein exerts such different morphological alterations remains unknown. RolB was shown to exhibit Tyr phosphatase activity (Filippini et al, 1996) and interact with 14-3-3 proteins (Moriuchi et al, 2004). RolB has no homology to any prokaryotic or eukaryotic proteins except the RolB (PLAST) family of oncoproteins in Agrobacterium species (Levesque et al, 1988;Otten and Schmidt, 1998).…”

“…RolB has no homology to any prokaryotic or eukaryotic proteins except the RolB (PLAST) family of oncoproteins in Agrobacterium species (Levesque et al, 1988;Otten and Schmidt, 1998). These RolB-related oncoproteins have been proposed to alter the developmental plasticity of transformed plants (Levesque et al, 1988;Moriuchi et al, 2004).…”

14-3-3 Proteins SGF14c and SGF14l Play Critical Roles during Soybean Nodulation

“…A survey involving 10 14-3-3 genes from tomato showed that three were induced by the Cf9-mediated hypersensitive defense response (Roberts and Bowles, 1999). A final example is that of 14-3-3 proteins suggested in Agrobacterium rhizogenes to bind RolB and direct it to the nucleus (Moriuchi et al, 2004).…”