The ability to modulate gene expression is crucial for studying gene function and programming cell behaviors. Combining the reliability of CRISPRi and the precision of optogenetics, the opto-CRISPRi technique is emerging as an advanced tool for live-cell gene regulation. Since previous versions of opto-CRISPRi often exhibit a no more than 10 folds' dynamic range due to the leakage activity, they are not suitable for targets that are sensitive to such leakage or critical for cell growth. Here, we describe a green-light activated CRISPRi system with high dynamic range (40-fold) and the flexibility of changing targets in Escherichia coli. Our optoCRISPRi-HD system can efficiently repress essential genes, non-essential genes or inhibit the initiation of DNA replication. Providing a regulative system with high resolution over space-time and extensive targets, our study would facilitate further researches involving complex gene networks, metabolic flux redirection or bioprinting.

Temperature is a major environmental factor that affects fruit storage, but the underlying molecular mechanism is poorly understood. Here, the differences in transcriptome, ethylene production, pulp softening of postharvest peach fruits were compared between common and high temperature storage conditions. High temperature storage resulted in a lower level of ethylene production and a slower fruit softening due to the decreased expression levels of ethylene biosynthetic genes and softening related enzymes. The MEKK1-MKK2-MPK4/6 genes had high expression levels in response to high temperature condition. The decreased expression of pectinesterase, polygalacturonase, pectate lyase, pectin methylesterase and the increased expression of expansin were observed in high temperature treatment. A series of genes related to membrane stability also showed lower transcription levels, such as peroxidase, lipoxygenase 3 and superoxide dismutase 1/2. These genes were co-expressed with different auxin response factors, ethylene response factors and they composed function modules collectively correlated to physiological changes. Finally, we proposed a model of the molecular response mechanism of peach fruit at high temperature which helps to develop new approaches for maintaining fruit quality during storage.