[P4] Crop Genetics and Physiology

[P4-25] Analysis on the Roles of Vacuolar Invertase Isoform, OsINV3 in Root Development of Rice

*Nominated for Presentation Awards

^○Natsumi Ueda¹, Ryutaro Morita¹, Tatsuro Hirose², Junko Yamagishi¹, Naohiro Aoki¹ (1.Graduate School of Agricultural and Life Sciences, the University of Tokyo, Japan, 2.Faculty of Agriculture, Takasaki University of Health and Welfare, Japan)

Root system is the only organ to absorb water and nutrient from soil, therefore it is an important factor for crop growth and yield. Carbon required for root development is supplied exclusively from shoot, however, the relationship between root development and metabolism of photoassimilates has been yet unknown. Here, we analysed the sugar metabolism in the root of rice inv3 mutant, in which OsINV3 a vacuolar invertase gene, is knocked out. The mutant was compared with wild-type (cv. Nipponbare) to clarify the role of sucrose degradation in root development.
Fresh weights of shoot, main roots and lateral roots were significantly smaller in inv3, while fresh weight of root tips was almost same level as wild-type. Non-structural carbohydrate (starch and soluble sugars) contents of main roots were not different in both lines. Although the sucrose contents in root tips and lateral roots of the mutant were more than twice that of the wild-type the glucose content in lateral roots of inv3 was significantly lower in the mutant than in the wild-type. Moreover, the fructose content in root tips and lateral roots of the mutant decreased to approximately one-seventh and one-third, respectively, compared to the wild-type. Whole root length in inv3 was also shorter than in the wild-type. These results imply that OsINV3 functions especially in lateral roots and root tips for their elongation.