Rice-duck co-culture benefits grain 2-acetyl-1-pyrroline accumulation and quality and yield enhancement of fragrant rice

Rice-duck co-culture is an integrated farming technology that benefits rice production, grain quality, and ecological sustainability in paddy fields. However, little is known about the effects of rice-duck co-culture on enzyme activity involved in the biosynthesis of 2-acetyl-1-pyrroline (2-AP), the volatile that gives fragrant rice its' distinctive and sought-after aroma. The present study aimed to examine the influence of rice-duck co-culture on the photosynthesis, yield, grain quality, rice aroma, and the enzymes involved in 2-acetyl-1-pyrroline biosynthesis in the cultivar Meixiangzhan 2 during the early and late rice growing seasons of 2016 in Guangzhou, China. We compared the rice grown in paddy fields with and without ducks. We found that rice-duck co-culture not only improved the yield and quality of fragrant rice grain, but also promoted the precursors of 2-AP biosynthesis formation and 2-AP accumulation in the grain. Grain 2-AP content in rice-duck co-culture was noticeably increased with 9.60% and 20.81% in early and late seasons, respectively. Proline and pyrroline-5-carboxylic acid (PSC) (precursors of 2-AP biosynthesis) and the activity of enzymes such as proline dehydrogenase (ProDH), omithine aminotransferase (OAT) and Delta(1) pyrroline-5-carboxylic acid synthetase (P5CS) were all improved by 10.15%-12.99%, 32.91%-47.75%, 17.81%-26.71%, 6.25%-21.78%, and 10.58%-38.87% under rice-duck co-culture in both seasons, respectively. Overall, our results suggest that rice-duck co-culture is an environmentally-friendly and sustainable approach to improving rice aroma and grain quality of fragrant rice. (C) 2019 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.