Plant chip for high-throughput phenotyping of Arabidopsis.

We report on the development of a vertical and transparent microfluidic chip for high-throughput phenotyping of Arabidopsis thaliana plants. Multiple Arabidopsis seeds can be germinated and grown hydroponically over more than two weeks in the chip, thus enabling large-scale and quantitative monitoring of plant phenotypes. The novel vertical arrangement of this microfluidic device not only allows for normal gravitropic growth of the plants but also, more importantly, makes it convenient to continuously monitor phenotypic changes in plants at the whole organismal level, including seed germination and root and shoot growth (hypocotyls, cotyledons, and leaves), as well as at the cellular level.

Electrospun nanofibrous membranes for temperature regulation of microfluidic seed growth chips.

This paper reports a simple and effective approach to control statistical pore size distributions within electrospun nanofibrous membranes (ENMs), by choosing appropriate spinning times of electro-spinning deposition. Mean pore diameter of ENMs decreases exponentially with increasing spinning time. This pore-size control method is demonstrated to regulate amount of heat energy reaching microfluidic seed growth chips (SGC) and thus growth temperature of seeds on the chips, without using sophisticated semiconductor manufacturing techniques or additional on-chip electronic circuits.

Genetic modification of low phytic acid 1-1 maize to enhance iron content and bioavailability.

High phytate content in staple food crops is a major barrier to successful iron biofortification. We have exploited the low phytic acid 1-1 (lpa1-1) mutant of maize to generate transgenic plants with up-to 70 μg/g seed iron through the endosperm-specific overexpression of soybean ferritin, resulting in more than 2-fold improvement in iron bioavailability. The levels of bioavailable seed iron achieved in this study greatly exceed any achieved thus far and closely approach values estimated to have a nutritional impact on target populations.

Chloroplast photooxidation-induced transcriptome reprogramming in Arabidopsis immutans white leaf sectors.

Arabidopsis (Arabidopsis thaliana) immutans (im) has green and white sectoring due to the action of a nuclear recessive gene, IMMUTANS. The green sectors contain normal-appearing chloroplasts, whereas the white sectors contain abnormal chloroplasts that lack colored carotenoids due to a defect in phytoene desaturase activity. Previous biochemical and molecular characterizations of the green leaf sectors revealed alterations suggestive of a source-sink relationship between the green and white sectors of im.

Quantification of ferritin from staple food crops.

Ferritin-iron has been shown to be as bioavailable as ferrous sulfate in humans. Thus, biofortification to breed crops with high ferritin content is a promising strategy to alleviate the global iron deficiency problem. Although ferritin is present in all food crops, its concentration varies between species and varieties.

Alterations in photosynthesis in Arabidopsis lacking IMMUTANS, a chloroplast terminal oxidase.

Green and white variegation in the Arabidopsis immutans (im) mutant is caused by a nuclear recessive gene. The green sectors contain cells with normal-appearing chloroplasts, while cells in the white sectors have photooxidized plastids lacking organized lamellae. In the present experiments, we found that the green im sectors have enhanced rates of carbon assimilation (monitored by (14)CO(2) uptake) and that there are corresponding increases in the activities of Rubisco and SPS, elevated starch and sucrose pool sizes, and an altered pattern of carbohydrate partitioning that favors sucrose over starch.

Arabidopsis variegation mutants: new insights into chloroplast biogenesis.

Plant variegations are characterized by the presence of white sectors in normally green tissues and organs. Whereas the white sectors contain defective plastids that lack coloured pigments, the green sectors contain morphologically normal chloroplasts. Variegation mutants are defective in chloroplast developmental processes and arise due to mutations in nuclear or organellar genes.

Control of chloroplast redox by the IMMUTANS terminal oxidase.

Variegation mutants offer excellent opportunities to study interactions between the nucleus-cytoplasm, the chloroplast, and the mitochondrion. Variegation in the immutans (im) mutant of Arabidopsis is induced by a nuclear recessive gene and the extent of variegation can be modulated by light and temperature. Whereas the green sectors have morphologically normal chloroplasts, the white sectors are devoid of pigments and accumulate a colourless carotenoid, phytoene.

Differential expression of fatty acid synthase genes, Acl, Fat and Kas, in Capsicum fruit.

The biosynthesis of capsaicinoids in the placenta of chilli fruit is modelled to require components of the fatty acid synthase (FAS) complex. Three candidate genes for subunits in this complex, Kas, Acl, and Fat, isolated based on differential expression, were characterized. Transcription of these three genes was placental-specific and RNA abundance was positively correlated with degree of pungency.