Potential of Rice-Flour Jelly Made from High-Amylose Rice as a Dysphagia Diet: Evaluation of Pharyngeal Residue by FEES.

Dysphagia diets are recommended to prevent choking and aspiration in people with dysphagia; however, rice-porridge and mashed rice-porridge, which are used as staple foods for people with dysphagia in Japan, are time-consuming to prepare. The National Agriculture and Food Research Organization has found jelly-like food products made from high-amylose rice-flour (rice-flour jelly) to be easy to prepare with a texture suitable for dysphagia diets. To investigate the potential of rice-flour jelly for the dysphagia diet, we evaluated the amount of pharyngeal residue after swallowing rice-flour jelly using fiberoptic endoscopic evaluation of swallowing and compared it with those of rice-porridge, mashed rice-porridge, and fruit jelly. We enrolled 70 participants (43 males and 27 females, aged 32-96 years, median 74.5 years) and evaluated their pharyngeal residue using the Yale Pharyngeal Residue Severity Rating Scale which includes five levels from I (none) to V (severe). Statistical analysis showed that level I was more common in fruit jelly for vallecula residue and pyriform sinus residue, and level III (mild) was more common in rice-porridge for vallecula residue (p < 0.05). No differences of pharyngeal residue were found in rice-flour jelly or mashed rice-porridge. No significant difference was observed in the number of participants with laryngeal penetration or aspiration. Therefore, rice-flour jelly is a suitable alternative to rice-porridge as a staple food for people with dysphagia in terms of food texture.

Genetic region responsible for the differences of starch properties in two glutinous rice cultivars in Hokkaido, Japan.

Starch properties are major determinants of grain quality and food characteristics in rice (Oryza sativa L.). Control of starch properties will lead to the development of rice cultivars with desirable characteristics. We performed quantitative trait locus analysis and detected a putative region on chromosome 2 associated with phenotypic variation of starch properties in two glutinous rice varieties developed in the Hokkaido region of Japan: 'Kitayukimochi', which has a low pasting temperature and creates soft rice cakes, and 'Shirokumamochi', which has a high pasting temperature and creates hard rice cakes. Starch branching enzyme IIb (SbeIIb) was identified as a candidate gene within the region. Sequence analysis of SbeIIb in parental lines identified two single-nucleotide polymorphisms (SNPs) with non-synonymous mutations in the coding region of the 'Shirokumamochi' genotype (SbeIIbsr ). We genotyped over 100 rice cultivars, including 28 rice varieties in the Honshu region of Japan, using the CAPS marker, which was designed using one of the SNPs. However, SbeIIbsr was not found in rice cultivars in Honshu. Distribution analysis indicated that SbeIIbsr was introduced to the rice breeding population in Hokkaido from the American variety 'Cody' via the Hokkaido cultivar 'Kitaake'. As a result, SbeIIbsr was distributed only in progenies of 'Kitaake'.

Knockdown of an arbuscular mycorrhiza-inducible phosphate transporter gene of Lotus japonicus suppresses mutualistic symbiosis.

cDNA for a major arbuscular mycorrhiza (AM)-inducible phosphate (Pi) transporter of Lotus japonicus, LjPT3, was isolated from Glomus mosseae-colonized roots. The LjPT3 transcript was expressed in arbuscule-containing cells of the inner cortex. The transport activity of the gene product was confirmed by the complementation of a yeast mutant that lacks high-affinity Pi transporters. In contrast to most AM-inducible Pi transporters thus far reported, LjPT3 has an amino acid sequence that has much in common with those of other members of the Pht1 family of plant Pi transporters, such as StPT3 of potato. To understand better the physiological role of this AM-inducible Pi transporter, knockdown transformants of the gene were prepared through hairy root transformation and RNA interference. Under Pi-limiting conditions, the transformants showed a reduction of Pi uptake via AM and growth retardation. The transformants also exhibited a decrease in G. mosseae arbuscules. Additionally, when Mesorhizobium loti was inoculated into the knockdown transformants in combination with G. mosseae, necrotic root nodules were observed. Based on these findings, we consider that the genetically engineered host plants had monitored insufficient Pi uptake via AM or low expression of LjPT3, excluding the existing fungi and rhizobia and/or preventing further development of the fungal and nodule structures.