Fibrillar microfilaments associated with a high-amylose rice, goami 2, a mutant of ilpumbyeo, a high-quality japonica rice.
The ultrastructure of cooked and malt-treated cooked rice of Ilpumbyeo (IP) and its mutant Goami 2 (G2), which have extreme contrasts in physicochemical properties, cooking quality, and ultrastructural characteristics in raw grains (1, 2), was compared. In cooked rice of IP, starch granules in endosperm cells were evenly coalesced, appearing as homogeneously smooth sheetlike matrix and/or globules, whereas those in G2 were a heterogeneously coarse matrix in which a novel structural feature, the microfilaments, was embedded. In malt-treated cooked rice of IP, most starch was hydrolyzed by the malt enzymes, appearing as empty vacuoles surrounded by the cell wall, whereas that in G2 was highly resistant to malt treatment, remaining as distinct structural features, the malt-resistant compound starch granules. The property of G2's compound starch granules, which are tolerant of mechanical and chemical treatments thereby retaining their structural integrity (2) and of cooking and malt treatment thereby retaining their physical hardness, appears to play a major role in determining the quality of cooked rice of G2.
Kim
Kyung-Soo
KS
Division of Genetics and Breeding, National Institute of Crop Science, RDA, 209 Seodun-Dong, Gwonseon-Ku, Kyeonggi-Do, Republic of Korea. kskim@rda.go.kr
Kang
Hee-Jin
HJ
Hwang
In-Kyeong
IK
Hwang
Hung-Goo
HG
Kim
Tae-Young
TY
Choi
Hae-Chune
HC
D008841:Actin Cytoskeleton / Q000648:ultrastructure; D000688:Amylose / Q000032:analysis*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006358:Hot Temperature; D009154:Mutation; D012275:Oryza / Q000737:chemistry / Q000235:genetics* / Q000648:ultrastructure*; D012639:Seeds / Q000737:chemistry* / Q000648:ultrastructure*; D013213:Starch / Q000032:analysis
D013213:Starch; D000688:Amylose