RESUMEN
Sorghum-sudangrass hybrids are widely used for forage and silage in the animal husbandry industry due to their hardiness. The heterozygous first generation of sorghum-sudangrass hybrids displays performance superior to their homozygous, parental inbred lines. In order to study the molecular details underlying its heterosis, the leaves of sorghum-sudangrass hybrids and their parents were compared using mass spectrometry-based proteomics. Results showed that among the 996 proteins that were identified, 32 proteins showed 'additive accumulation expression patterns', indicating that the protein abundance in sorghum-sudangrass hybrids showed no significant difference from the average of their parents. Additionally, 74 proteins showed 'nonadditive accumulation expression patterns' (the proteins abundance in the hybrids showed significant difference from the average of their parents). Both additive and nonadditive proteins were mainly involved in photosynthesis and carbohydrate metabolism. More upregulated additive and nonadditive proteins were in the hybrids than in their parents, suggesting that additive and nonadditive proteins are essential to the vigor of sorghum-sudangrass hybrids. The nonadditive proteins were enriched in photosynthesis, carbohydrate metabolism, and protein oligomerization, but the additive proteins were not enriched in any pathway, which indicated that the nonadditive proteins could be greater contributors to heterosis than additive proteins. Furthermore, the highly activated photosynthetic pathway in nonadditive proteins implies that photosynthesis in hybrids is heightened to assimilate more organic matter, resulting in an increased yield. Our results provide a proof-of-concept that reveals the molecular components of heterosis in sorghum-sudangrass hybrid leaves and serves as an important step for future genetic manipulation of specific proteins to improve the performance of hybrids.
Asunto(s)
Vigor Híbrido/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sorghum/genética , Sorghum/metabolismo , Alimentación Animal , Regulación de la Expresión Génica de las Plantas , Hibridación Genética , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Mapas de Interacción de Proteínas , Proteoma/genética , Proteoma/metabolismo , Proteómica , Regulación hacia ArribaRESUMEN
A total of 57 498 non-redundant ESTs were identified from 210 878 ESTs of Sorghum in NCBI by sequence analysis. In all, 3 338 SSRs were distributed in 3 116 ESTs with an average frequency of one SSR per 11.28 kb, which included 215 SSR motifs. Analysis of SSR motifs revealed that the trinucleotides were major motifs, accounting for 68.33%.The dinucleotides motifs accounted for 17.97%. There were 1 694 sequences from 3 338 EST-SSR sequences could be designed into primers and the proportion was 50.75%. Fourteen primers were selected to amplify EST-SSR loci with 50 collections of Sorghum bicolor × S. sudanenes, 7 collections of S. bicolor and 3 collections of S. sudanenes. Seventy-two allele variations were detected and the frequency was 5.14 gene loci per primer. The polymorphism index of each primer was in the range of 0.54-0.93. The genetic distance ranged from 0.1646 to 0.6398. This showed abundant genetic diversity in the materials. The materials were divided into 5 groups with clustering analysis of EST-SSR data. Each group included the varieties with similar parents or similar regional distribution. Meanwhile, 4 specific molecular markers were found. Primer D1763 was specific in the registered variety GB-4-2 which was the progeny of S. bicolor 314A × S. sudanenes White Skull. The marker was specific in justification of the germ difference. These results showed that the EST-SSR was an effective marker for genetic diversity analysis and specificity studies on S. bicolor × S. sudanenes.