Autophagy-deficient Arabidopsis mutant atg5, which shows ultraviolet-B sensitivity, cannot remove ultraviolet-B-induced fragmented mitochondria.
Photochem Photobiol Sci
; 19(12): 1717-1729, 2020 Dec 01.
Article
em En
| MEDLINE
| ID: mdl-33237047
ABSTRACT
Mitochondria damaged by ultraviolet-B radiation (UV-B, 280-315 nm) are removed by mitophagy, a selective autophagic process. Recently, we demonstrated that autophagy-deficient Arabidopsis thaliana mutants exhibit a UV-B-sensitive phenotype like that of cyclobutane pyrimidine dimer (CPD)-specific photolyase (PHR1)-deficient mutants. To explore the relationship between UV-B sensitivity and autophagy in UV-B-damaged plants, we monitored mitochondrial dynamics and autophagy in wild-type Arabidopsis (ecotype Columbia); an autophagy-deficient mutant, atg5; a PHR1-deficient mutant, phr1; an atg5 phr1 double mutant; and AtPHR1-overexpressing (AtPHR1ox) plants following high-dose UV-B exposure (1.5 W m-2 for 1 h). At 10 h after exposure, the number of mitochondria per mesophyll leaf cell was increased and the volumes of individual mitochondria were decreased independently of UV-B-induced CPD accumulation in all genotypes. At 24 h after exposure, the mitochondrial number had recovered or almost recovered to pre-exposure levels in plants with functional autophagy (WT, phr1, and AtPHR1ox), but had increased even further in atg5. This suggested that the high dose of UV-B led to the inactivation and fragmentation of mitochondria, which were removed by mitophagy activated by UV-B. The UV-B-sensitive phenotype of the atg5 phr1 double mutant was more severe than that of atg5 or phr1. In wild-type, phr1, and AtPHR1ox plants, autophagy-related genes were strongly expressed following UV-B exposure independently of UV-B-induced CPD accumulation. Therefore, mitophagy might be one of the important repair mechanisms for UV-B-induced damage. The severe UV-B-sensitive phenotype of atg5 phr1 is likely an additive effect of deficiencies in independent machineries for UV-B protection, autophagy, and CPD photorepair.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Arabidopsis
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Proteínas de Arabidopsis
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Proteína 5 Relacionada à Autofagia
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Mitocôndrias
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Mutação
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Photochem Photobiol Sci
Assunto da revista:
BIOLOGIA
/
QUIMICA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Japão