Comprehensive evaluation of the breeding value of OsPUP7 in rice

Gene editing has emerged as a powerful tool in crop breeding, particularly for rice, enabling the creation of germplasm and trait improvement. A thorough understanding of gene functions is essential for precise and efficient crop enhancement. OsPUP7 encodes a purine permease involved in cytokinin transport. However, the effects of OsPUP7 deficiency on rice growth and development, as well as its potential application value in rice breeding, remain unclear. This study analyzed the expression patterns of OsPUP7 in rice, constructed OsPUP7 knockout lines, and conducted three consecutive years of field trials to systematically evaluate the effects of OsPUP7 knockout on rice agronomic traits, yield traits, quality, resistance, and seed germination. The results showed that OsPUP7 is primarily expressed in panicles and grains. OsPUP7 knockout had no significant effect on heading date, plant height, number of panicles per plant, panicle length, primary branches, or single-plant yield, but significantly reduced the number of secondary branches and grains per panicle. At the same time, OsPUP7 knockout significantly increased grain length and the length-to-width ratio, reduced grain thickness, but had no significant effect on grain width and thousand-grain weight. In addition, the knockout of OsPUP7 generally does not affect milling quality, nutritional properties, or cooking quality. OsPUP7 knockout also had no significant effect on blast resistance, salt tolerance and seed germination. Based on the comprehensive evaluation above, we conclude that OsPUP7 is a potential and efficient target gene for improving rice grain shape using gene editing technology.