Rice AP2 Transcription Factor

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Rice AP2 transcription factor overexpression increases biomass accumulation and grain yield, while also exhibiting tolerance to abiotic stress Description: Rice Transcription Factor Overexpression Increases Biomass Accumulation and Grain Yield while Simultaneously Enhancing Tolerance to Stresses Problem Addressed: Global population growth puts significant strain on energy and food securities. Through gene discovery and plant biotechnology, we aim to address these issues. Description of Technology: The technology provides methods for improving crop yield, biomass accumulation, and stress tolerance.  According to the technology, a novel transcription factor termed MPG1 (Makes-Plants-Gigantic-1), which when over-expressed impacts grain yield, biomass, and abiotic and biotic stress tolerance when compared to wild-type plants. The technology further provides methods using recombinant expression cassettes, gene-editing, transgenic plants, and breeding methods. Innovation Details: Rice plants that over-express a novel, previously un-described transcription factor exhibit significantly increased biomass and seed yield compared to wild-type plants, and resistance to abiotic stress. This was discovered through the analysis of a rice T-DNA insertion mutant possessing increased biomass and seed yield compared to wild-type plants. The presence of the T-DNA insertion and plant biomass was tracked across multiple generations. Tracked over several generations, the mutant exhibited as high as a 7.4-fold increase in biomass and a simultaneous 3.6-fold increase in seed yield compared to segregating wild-type plants (the highest fold increases are when plants are grown under stressful growth conditions). The mpg1 insertion mutant also exhibited a delay in flowering time by an average of 16 days compared to wild-type plants. The longer vegetative growth period only partially accounted for the increased biomass. Insertion mutants also possess longer and wider leaves, and increased tiller girth compared to wild-type plants.                                                          The insertion caused a mutagenic event that resulted in the over expression of a nearby gene. Multiple methods, including RT-PCR, ddPCR, and RNA-seq, documented the over expression of this gene in the presence of the T-DNA insertion. Over-expression pattern and phenotype have correlated 100% across multiple generations, including in segregating backcrossed populations. The gene is a transcription factor belonging to a large superfamily of transcription factors in plants. Further phenotypic analysis showed that the increase in biomass is positively influenced by abiotic (and possibly) biotic stress. Mutant plants placed under drought, pH, and salt stress had substantially higher yields than wild type controls. Key Benefits: Significantly improved plant yield: plant biomass & seed yield Provides a degree of stress tolerance Market Analysis: Crops such as corn, rice, wheat, canola and soybean account for over half the total human caloric intake, whether through direct consumption of the seeds themselves or through consumption of meat products raised on processed seeds. They are also a source of sugars, oils and many kinds of metabolites used in industrial processes. Abiotic stress is the primary cause of crop loss worldwide, causing average yield losses more than 50% for major crops. It is expected that rice alone will need to achieve an annual global volumetric production rate of 800 million tons per year by 2025 (Kubo, (2004) Journal of Food Distribution & Research 35:128-142). Additionally, for many crops, yield increases have significantly slowed as much of the genetic potential for increases have already been exploited. Thus, grain yield improvements by conventional breeding have nearly reached a plateau in crop plants.