Genetic control of lysine metabolism in maize endosperm mutants

Abstract

The capacity of three maize endosperm opaque mutants (o10, o11 and o13) to accumulate soluble lysine in the seed in relation to their wildtype counterpart, W22+, was investigated. The W22o13 and W22o11 mutants exhibited 278% and 186% increases in soluble lysine, respectively, while for W22o10, a 36% decrease was observed, compared with the wildtype. A quantitative and qualitative study of the N constituents of the endosperm has been conducted and data obtained for the total protein, non-protein N, soluble amino acids, albumins / globulins, zeins and glutelins present in the seed of the mutants. Following 2D–PAGE, a total of 38 different forms of zein polypeptides were detected and considerable differences were noted between the three mutant lines. The metabolism of lysine was also studied by analysis of the enzymes aspartate kinase, homoserine dehydrogenase, lysine 2-oxoglutarate reductase and saccharopine dehydrogenase, which exhibited major changes in activity, depending on the genotype, suggesting that the mutant genes may have distinct regulatory activities.

Biochemical and histological characterization of tomato mutants

“…The use of mutants has been shown to be an extremely powerful tool for general use in biology (Azevedo et al 1990, 2004a, b, Brennecke et al 1996. Our group has consistently produced mutants or introgressed mutations into the tomato MT cultivar (Carvalho et al 2011a).…”

Rapid screening for selection of heavy metal-tolerant plants

“…Research on mutagenesis is focused largely on the establishment of mutants with alterations for a potential use in plant breeding or which are important for the study of a gene function, causing mutations that can lead to the gain or loss of the function of certain genes (Azevedo et al 1990, Brennecke et al 1996, Gaziola et al 1999, Azevedo et al 2004a, 2004b. There are several classical methods of mutagenesis using physical agents such as γ -rays, x -rays and fast neutrons, or chemical agents, e.g., methyl ethanesulfonate (MES), methyl methanesulfonate (MMS), diethyl sulfate (DES), and nitrosoguanidine (NTG, NG, MNNG), among others, which have been successfully used to obtain mutant plants tolerant to biotic (Pathirana 1992, Adu-Ampomah et al 1996, Bhagwat 1998, Jansen and Schaffrath 2009 and to abiotic stresses (Nawrot et al 2001, Zhu 2003, Saleem 2005, Tsyganov et al 2007, Lang and Buu 2008, Koch et al 2010, Kumar et al 2010.…”

Caracterização das proteínas de reserva em linhagem QPM e estudo bioquímico da enzima homoserina quinase (HK) em sementes de milho (Zea mays L.)

“…Com o surgimento do mutante o2, na década de 60 (MERTZ et al, 1964) (AZEVEDO et al, 2003;AZEVEDO et al, 2004a;AZEVEDO et al, 2004b).…”

“…Estes dados foram também observados por Azevedo et al (2003) ao estudar o genótipo selvagem OH43+ e seu mutante OH43o2, no qual a concentração de glutelina aumentou 2,5 vezes ao ser comparado com seu selvagem. Este resultado também é semelhante ao encontrado no selvagem W22+ com relação a seu mutante W22o11 (AZEVEDO et al, 2004a) Analisando as linhagens 161, fornecidas pela EMBRAPA, nota-se que a linhagem L161q…”