Functional analysis on sucrose transporters in sweet potato / 生物工程学报

Sweet potato is an important food crop that can also be used as an industrial raw material. Sucrose is the main form of long-distance carbohydrate transport in plants, and sucrose transporter (SUT) regulates the transmembrane transport and distribution of sucrose during plant growth and metabolism. Moreover, SUT plays a key role in phloem mediated source-to-sink sucrose transport and physiological activities, supplying sucrose for the sink tissues. In this study, the full-length cDNA sequences of IbSUT62788 and IbSUT81616 were obtained by rapid amplification of cDNA ends (RACE) cloning according to the transcripts of the two SUT coding genes which were differentially expressed in sweet potato storage roots with different starch properties. Phylogenetic analysis was performed to clarify the classification of IbSUT62788 and IbSUT81616. The subcellular localization of IbSUT62788 and IbSUT81616 was determined by transient expression in Nicotiana benthamiana. The function of IbSUT62788 and IbSUT81616 in sucrose and hexose absorption and transport was identified using yeast functional complementarity system. The expression pattern of IbSUT62788 and IbSUT81616 in sweet potato organs were analyzed by real-time fluorescence quantitative PCR (RT-qPCR). Arabidopsis plants heterologous expressing IbSUT62788 and IbSUT81616 genes were obtained using floral dip method. The differences in starch and sugar contents between transgenic and wild-type Arabidopsis were compared. The results showed IbSUT62788 and IbSUT81616 encoded SUT proteins with a length of 505 and 521 amino acids, respectively, and both proteins belonged to the SUT1 subfamily. IbSUT62788 and IbSUT81616 were located in the cell membrane and were able to transport sucrose, glucose and fructose in the yeast system. In addition, IbSUT62788 was also able to transport mannose. The expression of IbSUT62788 was higher in leaves, lateral branches and main stems, and the expression of IbSUT81616 was higher in lateral branches, stems and storage roots. After IbSUT62788 and IbSUT81616 were heterologously expressed in Arabidopsis, the plants grew normally, but the biomass increased. The heterologous expression of IbSUT62788 increased the soluble sugar content, leaf size and 1 000-seed weight of Arabidopsis plants. Heterologous expression of IbSUT81616 increased starch accumulation in leaves and root tips and 1 000-seed weight of seeds, but decreased soluble sugar content. The results obtained in this study showed that IbSUT62788 and IbSUT81616 might be important genes regulating sucrose and sugar content traits in sweet potato. They might carry out physiological functions on cell membrane, such as transmembrane transport of sucrose, sucrose into and out of sink tissue, as well as transport and unloading of sucrose into phloem. The changes in traits result from their heterologous expression in Arabidopsis indicates their potential in improving the yield of other plants or crops. The results obtained in this study provide important information for revealing the functions of IbSUT62788 and IbSUT81616 in starch and glucose metabolism and formation mechanism of important quality traits in sweet potato.

Evaluación sensorial de tortas de camote (Ipomoea batatas), elaboradas con o sin hojas de camote, con niños en edad escolar en Nicaragua / Sensory evaluation among Nicaraguan school-age children of a sweet potato (Ipomoea batatas) snack prepared with and without sweet potato leaves

Objetivo: realizar una evaluación sensorial del camote (Ipomoea batatas), con pulpa anaranjada (CPA) clon 440189. Materiales y metódos: se realizó un estudio descriptivo de tortas de camote con una muestra de conveniencia de 290 escolares nicaragüenses de tercero a sexto grado. A la torta A se le adicionaron hojas de camote, siendo la torta B la formulación tradicional. En una primera etapa, 33 madres de familia dieron su opinión sobre las tortas. Luego, los niños las evaluaron mediante una escala hedónica de cinco puntos en la que 1 corresponde a ''no me gusta nada'' y 5 a ''me gusta mucho'' y expresaron su preferencia. Resultados: la mayoría de las madres aprobaron las recetas y calificaron positivamente su facilidad de preparación, el tiempo requerido, la accesibilidad de los ingredientes, la probabilidad de aceptación en los niños y la posibilidad de incluirlas en el menú escolar. El puntaje de aceptabilidad asignado por los niños para las tortas fue alto (con un promedio ± DE de 4,5 ± 0,7) y similar entre ellas (p=0,91). El 51% prefirió la torta A y el 49% la torta B (p=0,56). Conclusiones: ambas tortas son aceptadas sensorialmente por las madres y los niños, es factible la inclusión del CPA 440189 en recetas alimentarias del escolar nicaragüense.

Objective: acomplete a sensory evaluation of orange-fleshed sweet potato (OFSP) clone 440189. Materials and methods: a descriptive study was undertaken with a convenience sample of 290 Nicaraguan school-age children attending grades 3 to 6, who taste-tested a ''sweet potato cake'' recipe. Snack A had sweet potato leaves added to it; snack B did not. First, 33 mothers opined about the snacks. Then, children tested snacks A and B, assigning a value of 1 to 5 (from ''I don´t like it very much'' to ''I like it very much'') to each and indicating which snack they preferred. Results: most of the women gave a positive evaluation to the snacks in terms of ease of preparation, time required, access to ingredients, probability that the children would accept them, and possibility of including them in the school menu. Acceptability scores assigned by the children were high (mean ± SD of 4,5 + 0,7) and similar between the snacks (p=0,91). Fifty one percent preferred snack A and 49% preferred snack B (p=0,56). Conclusions: both snacks were accepted by the mothers and children suggesting that it is feasible to include OFSP clone 440189 into Nicaraguan school children´s meals.

Sensory evaluation of cakes prepared with orange-fleshed sweet potato flour (Ipomoea batatas L. ) / Evaluación sensorial de pasteles con harina de camote (Ipomoea batatas L. )

Objective: to assess students´ acceptability and preference for cakes prepared with orange-fleshed sweet potato flour (Ipomoea batatas L.). Materials and methods: the cakes were prepared with wheat flour (sample A) and a mixture where 40% of the wheat flour was replaced by orange-fleshed sweet potato flour (sample B). Questionnaires were applied to 100 students between 10 and 12 years old from a public school in the city of Rio de Janeiro; sensory acceptance and preference tests were also applied. Results: participants were on average 11,7 years old, 80% were 6th graders, 50% were female and 97% of the students reported liking the cakes. In this group, 14% reported consuming cakes less than once a month; 27%, 1-3 times per month; 37%, 1-4 times per week; 19%, 1-2 times a day; and only 2% reported never consuming them. Both cakes had high acceptability; with an average score of 9,27 (A) and 9,26 (B) out of a maximum of 10, without any significant differences in preference. Cake consumption was part of the children´s eating habits. Conclusions: cakes prepared with 40% sweet potato flour were as well accepted as conventional cakes. Further, a portion of this cake (60 g) can contribute up to 22% of daily vitamin A needs. Key words: sweet potato (Ipomoea batatas L.), food fortified, food analysis, sensory evaluation, consumer satisfaction, food preferences.

Objetivo: evaluar la aceptabilidad y preferencia de los estudiantes por los pasteles preparados con harina de camote (Ipomoea batatas L.). Materiales y metódos:los pasteles fueron preparados con harina de trigo (muestra A) y una mezcla donde se reemplazó el 40% de la harina de trigo por harina de camote (muestra B). Se aplicaron cuestionarios a 100 estudiantes entre 10 y 12 años de edad de una escuela pública en la ciudad de Río de Janeiro, a quienes se les aplicaron pruebas sensoriales de aceptación y preferencia. Resultados:los participantes tenían en promedio 11,7 años, 80% cursaban sexto grado, 50% eran mujeres y el 97% de los estudiantes reportaron gustarles los pasteles. En este grupo, 14% informó que consumían los pasteles menos de una vez al mes, 27%, 1-3 veces al mes, 37%, 1-4 veces por semana, 19%, 1-2 veces al día y sólo un 2% informó no consumirlos. Ambos pasteles tuvieron una alta aceptación, con puntuación media de 9,27 (A) y 9,26 (B) de un máximo de 10 sin diferencias significativas en la preferencia. El consumo de pasteles fue parte de los hábitos alimentarios de estos niños. Conclusiones: pasteles elaborados con 40% de harina de camote podría tener tan buena aceptación como los convencionales. Además, una porción de este pastel (60 g) puede alcanzar hasta 22% de las necesidades diarias de vitamina A.