Transient expression platforms allow short-term expression of candidate genes in the host plant, without the integration of transgenic cassettes into the host genome. The expression cassettes are delivered to the host cells either by Agrobacterium- or microprojectile-mediated approaches. Agrobacterium-mediated transformation is laborious as it needs mature plants, significant time-gap between transformation and observation of results, and also, it induces widespread gene expression changes that influences the dynamics of transgene expression. Microprojectile-based bombardment approach is expensive and requires specialized equipment to achieve transient expression in host cells. Given this, Page et al. have developed a highly-efficient protoplast transformation protocol for transient expression of transgenes in rice. Precisely, protoplast is isolated from 7-10 days old rice seedling and polyethylene glycol (PEG, 20%)-mediated protoplast transformation is performed (60 μL protoplast suspension combined with 5 μg of plasmid DNA in a volume of 10 μL, diluted with ddH2O). Incubating the mixture in the dark at room temperature (RT) for 25 mins allows transformation to occur, and the reaction is then terminated using W5 solution. The transformed protoplasts are pelleted down, resuspended in WI solution, aliquoted and incubated at RT for 16 hr to allow transgenic protein(s) to accumulate. Later, confocal imaging of transformed protoplasts is performed to study the signals from fluorescent reporter tagged to gene-of-interest in the plasmid. Overall, the optimized protocol reported a transformation efficiency of 30%. The procedure is ‘cheap’ as it requires no expensive chemicals, equipment and reagent. It is ‘fast’ as PEG-mediated transformation overcomes the need for vacuum infiltration and the cell-counting step is also skipped as the protocol ensures isolation of healthy protoplasts. Also, confocal imaging at 16-20 hr post-transformation further shortened the time taken to acquire the data. The protocol is ‘robust’ as it could be coupled to any high‐throughput cloning platform to screen large numbers of expression cassettes. It could also be adapted for functional studies including promoter analysis, comparing protein fusion cassettes, and screen the efficacy of gRNAs in CRISPR/Cas9 constructs. (Summary by Muthamilarasan Mehanathan) Plant Cell Environ 10.1111/pce.13542