Interspecific Rice Hybrid of Oryza sativa × Oryza nivara Reveals a Significant Increase in Seed Protein Content

Abstract

Wild species offer a potential reservoir of genetic variation for crop improvement. Besides the valuable genes for disease resistance that the wild species have provided for rice improvement, recent studies have shown that these wild species could also provide favorable alleles for the improvement of yield and yield-related traits. The present study reports yet another potential of wild relatives of rice, which involves the improvement of seed protein content. A significant increase in seed protein content was observed in an interspecific hybrid between Oryza sativa ssp. indica and the wild species Oryza nivara. The hybrid showed a protein content of 12.4%, which was 28 and 18.2% higher than those of the parents O. nivara and IR 64, respectively. The increase in protein content was dependent on the genetic background of the rice variety used in the hybridization. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of seed storage proteins demonstrated that a significant increase in prolamins and glutelins was mainly responsible for the elevated protein content of the hybrid. Amino acid analysis of seed proteins revealed that the hybrid had net gains of 19.5% in lysine and 19.4% in threonine over the O. nivara parent on a seed dry weight basis. Molecular analysis indicated that the increase in protein content of the hybrid was not a result of chromosomal rearrangements or transposable element activation, at least in the chromosomal regions containing seed storage protein genes. A preliminary genetic analysis of the F 2 segregating population showed that the inheritance of the increased protein content was polygenic in nature. The development of this interspecific hybrid offers a great potential for selecting new rice cultivars that combine the high yield and superior cooking quality of IR 64 with improved seed protein content.

Comparative Studies on Proximate and Some Mineral Composition of Selected Local Rice Varieties and Imported Rice Brands in Ghana

“…[21,22] reported that deposition of protein in rice grains depends on plethora of interrelated metabolic pathways involved in uptake of N, Fe and Zn from soil, their transport to source tissues such as culms and leaves and mobilization and/or remobilization to developing grains. Each of these processes is governed by several genes and influenced by environmental factors such as soil type, drought, fertilizers application, genotype, environment interaction [23,24].…”

SUB1A‐dependent and ‐independent mechanisms are involved in the flooding tolerance of wild rice species

“…, 1997), the study of these species have an interesting potential to unveil genetic traits associated with different stress resistance. Indeed, some reports have been recently published on this topic (Mahmoud et al. , 2008; Fukao et al.…”

“…Although major reproductive barriers exist between plants belonging to different genome groups, and the rate of success for intergenomic crosses is very low (Yan et al, 1997), the study of these species have an interesting potential to unveil genetic traits associated with different stress resistance. Indeed, some reports have been recently published on this topic (Mahmoud et al, 2008;Fukao et al, 2009;Koseki et al, 2010;Li et al, 2010;Philippe et al, 2010).…”

Enhancing the chelation capacity of rice to maximise iron and zinc concentrations under elevated atmospheric carbon dioxide

“…Without significant increases to the protein content of rice grain, it appears certain that the severity of PEM as a global nutritional disorder will increase significantly under future, CO 2 -enriched atmospheres. Grain protein content does, however, show considerable variability across rice varieties and conventional breeding may be a viable strategy for producing new cultivars with increased grain protein content (Kennedy and Burlingame 2003;Mahmoud et al 2008).…”