TY - JOUR
T1 - Rearrangement of Actin Cytoskeleton Mediates Invasion of Lotus japonicus Roots by Mesorhizobium loti
AU - Yokota, Keisuke
AU - Fukai, Eigo
AU - Madsen, Lene H
AU - Jurkiewicz, Anna
AU - Rueda, Paloma
AU - Radutoiu, Simona
AU - Held, Mark
AU - Hossain, Md Shakhawat
AU - Szczyglowski, Krzysztof
AU - Morieri, Giulia
AU - Oldroyd, Giles E D
AU - Downie, J Allan
AU - Nielsen, Mette W
AU - Rusek, Anna Maria
AU - Sato, Shusei
AU - Tabata, Satoshi
AU - James, Euan K
AU - Oyaizu, Hiroshi
AU - Sandal, Niels
AU - Stougaard, Jens
PY - 2009
Y1 - 2009
N2 - 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.
AB - 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.
U2 - 10.1105/tpc.108.063693
DO - 10.1105/tpc.108.063693
M3 - Journal article
C2 - 19136645
SN - 1040-4651
JO - Plant Cell
JF - Plant Cell
ER -