Carotenoid metabolism is induced in rice bran during very high temperature stress.

Background: Postharvest yellowing (PhY) causes yellowing in rice endosperm during conditions of high temperature and moisture. Rice bran was investigated as a model tissue for studying PhY and for determining the possibility of carotenoids as the source of the yellow color.

Results: A survey of different colored rice and wild (non-sativa) rice lines resulted in the identification of several purple bran lines having very low or no bran carotenoids.

Meiotic transmission of an in vitro-assembled autonomous maize minichromosome.

Autonomous chromosomes are generated in yeast (yeast artificial chromosomes) and human fibrosarcoma cells (human artificial chromosomes) by introducing purified DNA fragments that nucleate a kinetochore, replicate, and segregate to daughter cells. These autonomous minichromosomes are convenient for manipulating and delivering DNA segments containing multiple genes. In contrast, commercial production of transgenic crops relies on methods that integrate one or a few genes into host chromosomes; extensive screening to identify insertions with the desired expression level, copy number, structure, and genomic location; and long breeding programs to produce varieties that carry multiple transgenes.