ABI3
ABI gene family member 3 (New molecule including SH3) (Nesh) [NESH]
Publications[править]
The tonoplast intrinsic proteins TIP3;1 and TIP3;2 are specifically expressed during seed maturation and localized to the seed protein storage vacuole membrane. However, the function and physiological roles of TIP3s are still largely unknown. The seed performance of TIP3 knockdown mutants was analysed using the controlled deterioration test. The tip3;1/tip3;2 double mutant was affected in seed longevity and accumulated high levels of hydrogen peroxide compared with the wild type, suggesting that TIP3s function in seed longevity. The transcription factor ABSCISIC ACID INSENSITIVE 3 (ABI3) is known to be involved in seed desiccation tolerance and seed longevity. TIP3 transcript and protein levels were significantly reduced in abi3-6 mutant seeds. TIP3;1 and TIP3;2 promoters could be activated by ABI3 in the presence of abscisic acid (ABA) in Arabidopsis protoplasts. TIP3 proteins were detected in the protoplasts transiently expressing ABI3 and in ABI3-overexpressing seedlings when treated with ABA. Furthermore, ABI3 directly binds to the RY motif of the TIP3 promoters. Therefore, seed-specific TIP3s may help maintain seed longevity under the expressional control of ABI3 during seed maturation and are members of the ABI3-mediated seed longevity pathway together with small heat shock proteins and late embryo abundant proteins.
MeSH Terms
- Abscisic Acid
- Aquaporins
- Arabidopsis
- Arabidopsis Proteins
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Plant
- Promoter Regions, Genetic
- Seeds
- Transcription Factors
- Vacuoles
Keywords
- ABI3
- Arabidopsis
- TIP3.
- hydrogen peroxide
- seed longevity
Seed longevity is important to preserve crops and wild plants and it is limited by progressive cellular damage (aging) during storage. The induction of cellular stress defenses and the formation of the seed coat are crucial protecting events during seed development, a process mediated in Arabidopsis thaliana by the transcription factors LEC1, LEC2, FUS3 and the abscisic acid-activated ABI3. In order to identify novel determinants of seed longevity we have screened an activation-tagging mutant collection of Arabidopsis and isolated a dominant mutant with increased seed longevity under both natural and accelerated aging conditions. Molecular characterization indicates that the mutant phenotype is caused by over-expression of the At2g26130 gene encoding a RING-type zinc finger putative ubiquitin ligase. Loss of function of this gene in a T-DNA insertion mutant resulted in decreased seed longevity. We named this important gene for seed longevity RSL1 (from Ring finger of Seed Longevity1) and we could demonstrate ubiquitin ligase activity with the recombinant protein. Morphological alterations in shoot tissues of the RSL1 over-expressing plants and analysis of gibberellins levels suggest that RSL1 may increase gibberellins responses by some unknown mechanism. These results validate the forward genetic approach to seed longevity and anticipate the identification of many novel determinants of this important trait.
MeSH Terms
- Abscisic Acid
- Arabidopsis
- Arabidopsis Proteins
- Cellular Senescence
- DNA, Bacterial
- Gene Expression
- Genes, Plant
- Gibberellins
- Humans
- Longevity
- Mutagenesis, Insertional
- Phenotype
- Plant Shoots
- RING Finger Domains
- Seeds
- Stress, Physiological
- Transcription Factors
- Ubiquitin
- Ubiquitin-Protein Ligases
Keywords
- Accelerated aging
- Activation tagging
- Natural aging
- RING ubiquitin ligases
- Screening
- Seed longevity