Luo X.,China Agricultural University |
Luo X.,Key Laboratory of Crop Heterosis and Utilization of Ministry of Education |
Luo X.,Beijing Key Laboratory of Crop Genetic Improvement |
Luo X.,Key Laboratory of Crop Genetic Improvement and Genome of Ministry of Agriculture |
And 25 more authors.
Plant Science | Year: 2011
Many rice breeding programs have currently reached yield plateaus as a result of limited genetic variability in parental strains. Dongxiang common wild rice (Oryza rufipogon Griff.) is the progenitor of cultivated rice (Oryza sativa L.) and serves as an important gene pool for the genetic improvement of rice cultivars. In this study, heterotic loci (HLs) associated with six yield-related traits were identified in wild and cultivated rice and investigated using a set of 265 introgression lines (ILs) of O. rufipogon Griff. in the background of the Indica high-yielding cultivar Guichao 2 (O. sativa L.). Forty-two HLs were detected by a single point analysis of mid-parent heterosis values from test cross F1 offspring, and 30 (71.5%) of these HLs showed significantly positive effects, consistent with the superiority shown by the F1 test cross population in the six yield-related traits under study. Genetic mapping of hsp11, a locus responsible for the number of spikelets per panicle, confirmed the utility of these HLs. The results indicate that favorable HLs capable of improving agronomic traits are available. The identification of HLs between wild rice and cultivated rice could lead to a new strategy for the application of heterosis in rice breeding. © 2011.
Song Y.,Laboratory of Crop Heterosis and Utilization |
Song Y.,Beijing Key Laboratory of Crop Genetic Improvement |
Song Y.,Key Laboratory of Crop Genetic Improvement and Genome |
Song Y.,China Agricultural University |
And 24 more authors.
Grassland Science | Year: 2011
A molecular linkage map was developed for the tetraploid orchardgrass (Dactylis glomerata L.) from an F 1 pseudo-testcross population of 76 individuals derived from the cross between two individual plants of Akimidori, a Japanese cultivar and Loke, a Swedish cultivar. Two simple sequence repeat (SSR)-based parental linkage maps were constructed from 314 polymorphic homologous SSR markers derived from the same species. The Akimidori map consisted of 24 linkage groups (LGs) and had a total length of 562cM, with 168 loci and an average map density of 3.3cM. Five homologous LGs were detected on this map. The Loke map consisted of 26 LGs and had a total length of 745cM, with 227 loci and an average map density of 3.3cM. Seven homologous LGs were detected on this map. A consensus map with seven homologous LGs was developed from these using TetraploidMap software based on the double-simplex (segregated as 3:1) and duplex (segregated as 5:1) markers. This is the first linkage map of the tetraploid Dactlysis and these maps will be useful for quantitative trait locus (QTL) analysis, marker-assisted selection and breeding for important traits in orchardgrass in the future. © 2011 The Authors. Grassland Science © 2011 Japanese Society of Grassland Science.
Feng X.,China Agricultural University |
Feng X.,Key Laboratory of Crop Genomics and Genetic Improvement |
Feng X.,Key Laboratory of Crop Heterosis and Utilization of Ministry of Education |
Feng X.,Beijing Key Laboratory of Crop Genetic Improvement |
And 20 more authors.
Plant Cell, Tissue and Organ Culture | Year: 2011
Sorbitol promotes plantlet regeneration frequency (PRF) of rice calli. To better understand this phenomenon, calli of upland rice cv. HD65 were induced on medium containing 10 g sorbitol/L, and subcultured and regenerated on media containing 20 and 40 g sorbitol/L, respectively. Using complementary DNA (cDNA)-amplified fragment length polymorphism (AFLP) analysis, we investigated differential gene expression between sorbitol-supplemented (SC) and sorbitol-free calli (NC) during the regeneration stage. From >4,000 transcript-derived fragments (TDFs), we identified 118 differentially expressed TDFs between SC and NC. Of these, 37 were cloned and sequenced, and 12 were further confirmed by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR) analysis. Database searches indicated that 10 TDFs showed no significant homology to genes with known or putative functions, although they were previously reported to be expressed in rice calli. These cDNAs might encode novel proteins related to plantlet regeneration. Of all the 27 well-known TDFs, 35. 1% were highly expressed in SC, and had roles in signal transduction (13. 5%), transcription and translation (13. 5%), and regulation (8. 1%). Four TDFs were related to plant growth and regeneration: TDF5, TDF17, TDF21, and TDF26, which showed homologies to a nucleoside diphosphate kinase (NDPK), a cyclin, a receptor-like protein kinase precursor, and TCP-1, respectively. Furthermore, 35. 1% were related to metabolism, 27. 0% to energy, and 8. 1% to defense. These results suggest that, in addition to its roles as a carbon source and an osmotic regulator, sorbitol may also act as a chemical signal to directly or indirectly alter gene expression. Sorbitol exerts its effects via complex transcriptional networks to enhance PRF of calli. © 2011 Springer Science+Business Media B.V.
Ji Q.,China Agricultural University |
Ji Q.,Iowa State University |
Zhang M.,Yangzhou University |
Lu J.,Yangzhou University |
And 8 more authors.
Plant Physiology | Year: 2012
The S5 locus regulates spikelet fertility of indica/japonica hybrid rice (Oryza sativa). There are three alleles at the S5 locus, including an indica allele (S5i), a japonica allele (S5j), and a wide-compatibility allele (S5n). This study analyzed the molecular basis for S5-dependent reproductive isolation and compatibility of indica/japonica rice hybrids. Three S5 alleles were expressed at extremely low levels, and only in the ovary. S5n was more similar to S5i in both RNA and protein expression profiles. The S5 locus was not essential for embryo sac development, although deleterious interactions between S5i and S5j resulted in reduced rates of spikelet fertility. The yeast two-hybrid system was used to test direct interactions between S5-encoded proteins. The results indicated that the S5i- and S5j-encoded eukaryotic aspartyl proteases formed both homodimers and heterodimers, whereas the S5n-encoded aspartyl protease was incapable of dimerization. Site-directed mutagenesis revealed that a single amino acid difference between S5i- and S5j-encoded aspartyl proteases (phenylalanine/leucine at residue 273) was primarily responsible for embryo sac abortion. The S5 locus may have promoted the subspeciation of indica and japonica, but it also enables gene flow between them. © 2012 American Society of Plant Biologists.
Ye J.,China Agricultural University |
Xu M.,China Agricultural University |
Xu M.,Beijing Key Laboratory of Crop Genetic Improvement
Journal of Plant Physiology | Year: 2012
Microspores develop inside the anther, where they are surrounded by nourishing tapetal cells. However, many cellular processes occurring during microspore development in the locule are poorly characterized. The actin cytoskeleton is known to play a crucial role in various aspects of the plant developmental process. During pollen tube tip growth, actin cytoskeleton serves as an efficient molecular transportation track, although how it functions in pollen development is unknown. The plant actin bundler PLIM2s have been shown to regulate actin bundling in different cells. Here, we investigate the biological function of three Arabidopsis pollen-specific LIM proteins, PLIM2a, PLIM2b, and PLIM2c (collectively, PLIM2s), in pollen development and tube growth. Variable degrees of suppressed expression of the PLIM2s by RNA interference resulted in aberrant phenotypes. Complete suppression of the PLIM2s totally disrupted pollen development, producing abortive pollen grains and rendering the transgenic plants sterile. Partial suppression of the PLIM2s arrested pollen tube growth to a lesser extent, resulting in short and swollen pollen tubes. Finally, the PLIM2c promoter initiated expression in pollen during stamen filament elongation, and the PLIM2c protein was located on particle structures in the developing pollen grains in Arabidopsis. These suggest that the actin bundler, PLIM2s, are an important factor for Arabidopsis pollen development and tube growth. © 2011 Elsevier GmbH.