Polycomb-group (PcG) protein MULTICOPY SUPPRESSOR OF IRA1 (MSI1) protein is an evolutionarily conserved developmental suppressor and plays a crucial role in regulating epigenetic modulations. However, the potential role and function of MSI1 in fleshy fruits remain unknown. In this study, SlMSI1 was cloned and transformed into tomato to explore its function. The quantitative real-time PCR results showed that SlMSI1 was highly expressed in flowers and fruits and that its transcript and protein levels were significantly decreased in fruits after the breaker stage. Additionally, SlMSI1-overexpressing transgenic tomatoes displayed abnormal non-ripening fruit formation, whereas its suppression promoted fruit ripening in transgenic tomatoes. Quantitative real-time PCR assays also showed that RIN and its regulons were decreased in SlMSI1 overexpression transgenic tomato fruits. Furthermore, RNA-seq analysis demonstrated that SlMSI1 inhibits fruit ripening by negatively regulating a large set of fruit-ripening genes in addition to RIN and its regulons. Finally, genetic manipulation of SlMSI1 and RIN successfully prolonged the fruit shelf life by regulating the fruit-ripening genes in tomato. Our findings reveal a novel regulatory function of SlMSI1 in fruit ripening and provide a new regulator that may be useful for genetic engineering and modification of fruit shelf life.
Carrier Proteins/genetics , Carrier Proteins/physiology , Fruit/physiology , Nuclear Proteins/genetics , Nuclear Proteins/physiology , Plant Proteins/genetics , Plant Proteins/physiology , Solanum lycopersicum/physiology , Arabidopsis Proteins/genetics , Arabidopsis Proteins/physiology , Ethylenes/chemistry , Flowers/physiology , Fruit/genetics , Gene Expression Profiling , Gene Expression Regulation, Plant , Genes, Plant , Solanum lycopersicum/genetics , MADS Domain Proteins/genetics , MADS Domain Proteins/physiology , Plants, Genetically Modified/genetics , Plants, Genetically Modified/physiology , Polycomb-Group Proteins/genetics , Polycomb-Group Proteins/physiology , Real-Time Polymerase Chain Reaction , Sequence Analysis, RNA , Transcription Factors/genetics , Transcription Factors/physiology
Vacuole H(+)-ATPases (VHAs) are plant proton pumps, which play a crucial role in plant growth and stress tolerance. In the present study, we demonstrated that the apple vacuolar H(+)-ATPase subunit A (MdVHA-A) is highly conserved with subunit A of VHA (VHA-A) proteins from other plant species. MdVHA-A was expressed in vegetative and reproductive organs. In apple in vitro shoot cultures, expression was induced by polyethylene glycol (PEG)-mediated osmotic stress. We further verified that over-expression of MdVHA-A conferred transgenic tobacco seedlings with enhanced vacuole H+-ATPase (VHA) activity and improved drought tolerance. The enhanced PEG-mimic drought response of transgenic tobacco seedlings was related to an extended lateral root system (dependent on auxin translocation) and more efficient osmotic adjustment. Our results indicate that MdVHA-A is a candidate gene for improving drought tolerance in plants.
Droughts , Gene Expression Regulation, Plant , Malus/genetics , Nicotiana/genetics , Plant Proteins/genetics , Vacuolar Proton-Translocating ATPases/genetics , Adaptation, Physiological , Breeding , Malus/physiology , Plant Proteins/physiology , Plants, Genetically Modified/genetics , Plants, Genetically Modified/physiology , Seedlings/genetics , Seedlings/physiology , Stress, Physiological , Nicotiana/physiology , Vacuolar Proton-Translocating ATPases/physiology , Vacuoles/metabolism
It has been well documented that FERTILIZATION-INDEPENDENT ENDOSPERM (FIE) plays important regulatory roles in diverse developmental processes in model plant Arabidopsis thaliana. However, it is largely unknown how FIE genes function in economically important crops. In this study, MhFIE gene, which was previously isolated from apomictic tea crabapple (Malus hupehensis Redh. var. pingyiensis), was introduced into tomato. The hemizygous transgenic tomato lines produced curly leaves and decreased in seed germination. In addition, the co-suppression of the transgenic MhFIE and endogenous (SlFIE) genes occurred in homozygous transgenic tomatoes. As a result, FIE silencing brought about abnormal phenotypes during reproductive development in tomato, such as increased sepal and petal numbers in flower, a fused ovule and pistil and parthenocarpic fruit formation. A yeast two-hybrid assay and bimolecular fluorescence complementation (BiFC) demonstrated that MhFIE interacted with a tomato protein, EZ2 (SlEZ2). Its ectopic expression and SlFIE co-suppression notably influenced the expression of genes associated with leaf, flower, and fruit development. Therefore, together with other PcG proteins, FIE was involved in the regulation of vegetative and reproductive development by modulating the expression of related genes in plants.
Gene Expression Regulation, Plant/genetics , Malus/genetics , Plant Proteins/metabolism , Solanum lycopersicum/growth & development , Apomixis , Flowers/genetics , Flowers/growth & development , Flowers/metabolism , Fruit/genetics , Fruit/growth & development , Fruit/metabolism , Gene Expression , Germination , Solanum lycopersicum/genetics , Solanum lycopersicum/metabolism , Phenotype , Plant Leaves/genetics , Plant Leaves/growth & development , Plant Leaves/metabolism , Plant Proteins/genetics , Plants, Genetically Modified , RNA Interference , RNA, Plant/genetics , Real-Time Polymerase Chain Reaction , Reproduction , Seeds/genetics , Seeds/growth & development , Seeds/metabolism , Transformation, Genetic , Two-Hybrid System Techniques
