RRC ID 4681
Author Yokota K, Fukai E, Madsen LH, Jurkiewicz A, Rueda P, Radutoiu S, Held M, Hossain MS, Szczyglowski K, Morieri G, Oldroyd GE, Downie JA, Nielsen MW, Rusek AM, Sato S, Tabata S, James EK, Oyaizu H, Sandal N, Stougaard J.
Title Rearrangement of actin cytoskeleton mediates invasion of Lotus japonicus roots by Mesorhizobium loti.
Journal Plant Cell
Abstract Infection thread-dependent invasion of legume roots by rhizobia leads to internalization of bacteria into the plant cells, which is one of the salient features of root nodule symbiosis. We found that two genes, Nap1 (for Nck-associated protein 1) and Pir1 (for 121F-specific p53 inducible RNA), involved in actin rearrangements were essential for infection thread formation and colonization of Lotus japonicus roots by its natural microsymbiont, Mesorhizobium loti. nap1 and pir1 mutants developed an excess of uncolonized nodule primordia, indicating that these two genes were not essential for the initiation of nodule organogenesis per se. However, both the formation and subsequent progression of infection threads into the root cortex were significantly impaired in these mutants. We demonstrate that these infection defects were due to disturbed actin cytoskeleton organization. Short root hairs of the mutants had mostly transverse or web-like actin filaments, while bundles of actin filaments in wild-type root hairs were predominantly longitudinal. Corroborating these observations, temporal and spatial differences in actin filament organization between wild-type and mutant root hairs were also observed after Nod factor treatment, while calcium influx and spiking appeared unperturbed. Together with various effects on plant growth and seed formation, the nap1 and pir1 alleles also conferred a characteristic distorted trichome phenotype, suggesting a more general role for Nap1 and Pir1 in processes establishing cell polarity or polar growth in L. japonicus.
Volume 21(1)
Pages 267-84
Published 2009-1-1
DOI 10.1105/tpc.108.063693
PII tpc.108.063693
PMID 19136645
PMC PMC2648097
MeSH Actins / genetics Actins / metabolism* Alleles Cloning, Molecular Cytoskeleton / metabolism* DNA, Plant / genetics Gene Expression Regulation, Plant Genes, Plant Lotus / genetics Lotus / metabolism Lotus / microbiology* Molecular Sequence Data Mutation Plant Proteins / genetics Plant Proteins / metabolism* Rhizobiaceae / growth & development* Root Nodules, Plant / cytology Root Nodules, Plant / metabolism Root Nodules, Plant / microbiology Sequence Alignment Sequence Analysis, DNA Symbiosis
IF 9.618
Times Cited 96
Lotus / Glycine Lotus japonicus