The present invention relates to a technique of increasing the size of plant seeds and the content of depot fat in the seeds by using a pyruvic acid transporter in charge of transporting pyruvic acid in a plant and, more specifically, to a composition for increasing the size of plant seeds and the content of depot fat in the seeds, the composition containing the BASS2 protein, which is a pyruvic acid transporter, or a gene encoding the protein, and to a method for increasing the size of plant seeds or the content of depot fat in the seeds, the method comprising a step of introducing the gene and a promoter for overexpressing the gene into a plant. According to the present invention, the fatty acid precursor can be increased by increasing the amount of pyruvic acid transported to the chromatophore at the time of forming seeds, thereby increasing the size of the seeds and the content of depot fat in the seeds, thus expecting the increase of productivity due to the increase in the seed yield. In addition, the content of depot fat in the seeds can be further increased through the increase in the size of the seeds, which correspond to a main plant fat storage organ, thereby significantly improving productivity of plant fat (oil) in a restricted space.La présente invention concerne une technique daugmentation de la taille de graines de plante et de la teneur en matière grasse de réserve dans les graines à laide dun transporteur dacide pyruvique chargé de transporter de lacide pyruvique dans une plante. Linvention concerne plus particulièrement une composition pour augmenter la taille de graines de plante et la teneur en matière grasse de réserve dans les graines, la composition contenant la protéine BASS2, qui est un transporteur dacide pyruvique, ou un gène codant pour la protéine, et un procédé permettant daugmenter la taille de graines de plante ou la teneur en matière grasse de réserve dans les graines, le procédé comprenant une étape consistant à introduire le gène e
