Arabidopsis DAL1 and DAL2, two RING finger proteins homologous to Drosophila DIAP1, are involved in regulation of programmed cell death.
Programmed cell death (PCD) is a precise, genetically controlled cellular process with important roles in plant growth, development, and response to biotic and abiotic stress. However, the genetic mechanisms that control PCD in plants are unclear. Two Arabidopsis genes, DAL1 and DAL2 (for Drosophila DIAP1 like 1 and 2), encoding RING finger proteins with homology to DIAP1 were identified, and a series of experiments were performed to elucidate their roles in the regulation of PCD and disease resistance. Expression of DAL1 and DAL2 genes was induced in Arabidopsis plants after inoculation with virulent and avirulent strains of Pseudomonas syrinage pv. tomato (Pst) DC3000 or after infiltration with fumonisin B1 (FB1). Plants with mutations in the DAL1 and DAL2 genes displayed more severe disease after inoculation with an avirulent strain of Pst DC3000, but they showed similar disease severity as the wild-type plant after inoculation with a virulent strain of Pst DC3000. Significant accumulations of reactive oxygen species (ROS) and increased cell death were observed in the dal1 and dal2 mutant plants after inoculation with the avirulent strain of Pst DC3000. The dal mutant plants underwent extensive PCD upon infiltration of FB1 and displayed higher levels of ROS accumulation, callose deposition, and autofluorescence than the wild-type plants. Our data suggest that DAL1 and DAL2 may act as negative regulators of PCD in Arabidopsis.
State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Huajiachi Campus, Hangzhou 310029, Zhejiang, People's Republic of China.
B M Vindhya S
BM
Basnayake
Dayong
D
Li
Huijuan
H
Zhang
Guojun
G
Li
Nasar
N
Virk
Fengming
F
Song
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins / Q000737:chemistry*; D005453:Fluorescence; D037341:Fumonisins / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005936:Glucans / Q000378:metabolism; D051034:Inhibitor of Apoptosis Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011549:Pseudomonas / Q000187:drug effects / Q000472:pathogenicity; D054829:RING Finger Domains; D017382:Reactive Oxygen Species / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D044767:Ubiquitin-Protein Ligases; D014774:Virulence / Q000187:drug effects
D051017:Apoptosis Regulatory Proteins; D029681:Arabidopsis Proteins; C557287:DAL2 protein, Arabidopsis; C111891:DIAP1 protein, Drosophila; D029721:Drosophila Proteins; D037341:Fumonisins; D005936:Glucans; D051034:Inhibitor of Apoptosis Proteins; D017382:Reactive Oxygen Species; C056933:fumonisin B1; C048306:callose; C000627978:SP1 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases