Kernel lysine content does not increase in some maize opaque2 mutants

Abstract

The recessive mutant allele of the opaque2 gene (o2) alters the endosperm protein pattern and increases the kernel lysine content of maize (Zea mays L.). In this study, sequencing results showed that the o2 mutant was successfully introgressed into 12 elite normal maize inbred lines by marker assisted selection (MAS). The average genetic similarity between these normal inbred lines and their o2 near-isogenic lines (NILs) was more than 95%. Kernel lysine content increased significantly in most of o2 NILs lines relative to normal elite inbreds, but remained unchanged in the genetic backgrounds Dan598o2 and Liao2345o2. Moreover, the kernel characteristics of these two o2 NILs did not differ from the other inbred lines. The results of lysine content analysis in the F1 hybrids between Liao2345o2 and Dan598o2 and other o2 NILs demonstrated that gene(s) other than opaque2 may control kernel lysine content in these two o2 NILs. The results of zein analysis showed that 22-kD α-zein synthesis was reduced or absent, and the 19-kD α-zein synthesis was greatly reduced compared with the recurrent parents in most o2 NILs except for Dan598o2 and Liao2345o2. Our results indicate that gene(s) other than opaque2 may play more important roles in zein synthesis and kernel lysine content in some maize genetic backgrounds.

Biotechnology for Enhanced Nutritional Quality in Plants

“…Unfortunately, the mutants also have softer endosperm, which increases mechanical damage and disease susceptibility and decreases yield. On the other hand, the results of a recent study with maize opaque-2 nearly isogenic lines suggests a genotype dependent role of opaque-2 rather than being an absolute determinant of zein synthesis and kernel lysine content (Zhao et al, 2012). Thus, the use of these mutants to breed maize with improved protein content is difficult.…”

Transposable Element rbg Induces the Differential Expression of opaque-2 Mutant Gene in Two Maize o2 NILs Derived from the Same Inbred Line

“…The maize inbred line liao2345/ o2 -1 is also not a QPM inbred line because its lysine and γ-zein concentrations were lower than those of CA339. In our previous study, liao2345/ o2 -1 was determined to be o2 non-high lysine maize [21].…”

“…CA339 is a QPM inbred line derived from pool33, which is from CIMMYT, and selected by Maize Research Center of Institute of Crop Sciences of CAAS; and liao2345 is a normal elite Chinese inbred line, cultivated by Maize Research Institute of Liaoning Academy of Agricultural Sciences. Two o2 NILs, liao2345/ o2 -1 and liao2345/ o2 -2, were selected from the two parents by MAS [21]. The pedigree and detailed information refer to Table 1.…”

“…Nearly all of the selected lines presented opaque kernels and elevated lysine concentration. In our previous work, we found that some o2 near-isogenic lines (NILs) have a wild-type kernel phenotype with unchanged lysine content, such as Liao2345 o2 and Dan598 o2 [21]. Surprisingly, another o2 NIL derived from liao2345 has an entirely different kernel phenotype with opaque endosperm that is identical to a typical o2 mutant individuals.…”

Caracterização das enzimas chaves para o controle do metabolismo de lisina em milho (Zea mays L.) geneticamente modificado

“…O milho é um cereal importante para a nutrição humana e animal, mas a carência de determinados aminoácidos essenciais como a lisina, limita o seu valor nutricional (ZHAO et al, 2012 -β-zeína (15 kDa) codificada por um gene, constitui cerca de 5 a 10% das zeínas;…”