Loss of Necrotic Spotted Lesions 1 associates with cell death and defense responses in Arabidopsis thaliana.
We isolated a lesion mimic mutant, necrotic spotted lesions 1 (nsl1), from Ds-tagged Arabidopsis thaliana accession No-0. The nsl1 mutant exhibits a growth retardation phenotype and develops spotted necrotic lesions on its rosette and cauline leaves. These phenotypes occur in the absence of pathogens indicating that nsl1 mutants may constitutively express defense responses. Consistent with this idea, nsl1 accumulates high levels of callose and autofluorescent phenolic compounds localized to the necrotic lesions. Furthermore RNA gel blot analysis revealed that genes associated with disease resistance activation are upregulated in the nsl1 mutants and these plants contain elevated levels of salicylic acid (SA). Crossing nsl1 with an SA deficient mutant, eds16-1, revealed that the nsl1 lesions and growth retardation are dependent upon SA. The nsl1 phenotypes are not suppressed under either the rar1-10 or sgt1b-1 genetic background. NSL1 encodes a novel 612aa protein which contains a membrane-attack complex/perforin (MACPF) domain, which is conserved in bacteria, fungi, mammals and plants. The possible modes of action of NSL1 protein in negative regulation of cell death programs and defense responses are discussed.
Noutoshi
Yoshiteru
Y
Plant Molecular Biology, RIKEN Tsukuba Institute, 3-1-1 Koyadai Tsukuba, Ibaraki 305-0074, Japan.
Kuromori
Takashi
T
Wada
Takuji
T
Hirayama
Takashi
T
Kamiya
Asako
A
Imura
Yuko
Y
Yasuda
Michiko
M
Nakashita
Hideo
H
Shirasu
Ken
K
Shinozaki
Kazuo
K
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000145:classification / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D016923:Cell Death; D017931:DNA Primers; D004251:DNA Transposable Elements; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D004251:DNA Transposable Elements; D018076:DNA, Complementary; D018744:DNA, Plant; D010940:Plant Proteins; D018749:RNA, Plant