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Wu L.,Southwest University | Guan Y.,Southwest University | Wu Z.,Southwest University | Yang K.,Southwest University | And 9 more authors.
Plant Cell Reports | Year: 2014

Key message: An ABC transporter gene (OsABCG15) was proven to be involved in pollen development in rice. The corresponding protein was localized on the plasma membrane using subcellular localization.Abstract: Wax, cutin, and sporopollenin are important for normal development of the anther cuticle and pollen exine, respectively. Their lipid soluble precursors, which are produced in the tapetum, are then secreted and transferred to the anther and microspore surface for polymerization. However, little is known about the mechanisms underlying the transport of these precursors. Here, we identified and characterized a member of the G subfamily of ATP-binding cassette (ABC) transporters, OsABCG15, which is required for the secretion of these lipid-soluble precursors in rice. Using map-based cloning, we found a spontaneous A-to-C transition in the fourth exon of OsABCG15 that caused an amino acid substitution of Thr-to-Pro in the predicted ATP-binding domain of the protein sequence. This osabcg15 mutant failed to produce any viable pollen and was completely male sterile. Histological analysis indicated that osabcg15 exhibited an undeveloped anther cuticle, enlarged middle layer, abnormal Ubisch body development, tapetum degeneration with a falling apart style, and collapsed pollen grains without detectable exine. OsABCG15 was expressed preferentially in the tapetum, and the fused GFP-OsABCG15 protein was localized to the plasma membrane. Our results suggested that OsABCG15 played an essential role in the formation of the rice anther cuticle and pollen exine. This role may include the secretion of the lipid precursors from the tapetum to facilitate the transfer of precursors to the surface of the anther epidermis as well as to microspores. © 2014, The Author(s). Source

Wu X.,Sichuan Agricultural University | Wu X.,Chinese Academy of Agricultural Sciences | Wu X.,Nanchong Academy of Agricultural science | Li Y.,Chinese Academy of Agricultural Sciences | And 4 more authors.
Theoretical and Applied Genetics | Year: 2014

To investigate the genetic structure of Chinese maize germplasm, the MaizeSNP50 BeadChip with 56,110 single nucleotide polymorphisms (SNPs) was used to genotype a collection of 367 inbred lines widely used in maize breeding of China. A total of 41,819 informative SNPs with minor allele number of more than 0.05 were used to estimate the genetic diversity, relatedness, and linkage disequilibrium (LD) decay. Totally 1,015 SNPs evenly distributed in the genome were selected randomly to evaluate the population structure of these accessions. Results showed that two main groups could be determined i.e., the introduced germplasm and the local germplasm. Further, five subgroups corresponding to different heterotic groups, that is, Reid Yellow Dent (Reid), Lancaster Sure Crop (Lancaster), P group (P), Tang Sipingtou (TSPT), and Tem-tropic I group (Tem-tropic I), were determined. The genetic diversity of within subgroups was highest in the Tem-Tropic I and lowest in the P. Most lines in this panel showed limited relatedness with each other. Comparisons of gene diversity showed that there existed some conservative genetic regions in specific subgroups across the ten chromosomes, i.e., seven in the Lancaster, seven in the Reid, six in the TSPT, five in the P, and two in the Tem-Tropical I. In addition, the results also revealed that there existed fifteen conservative regions transmitted from Huangzaosi, an important foundation parent, to its descendants. These are important for further studies since the outcomes may provide clues to understand why Huangzaosi could become a foundation parent in Chinese maize breeding. For the panel of 367 elite lines, average LD distance was 391 kb and varied among different chromosomes as well as in different genomic regions of one chromosome. This analysis uncovered a high natural genetic diversity in the elite maize inbred set, suggesting that the panel can be used in association study, esp. for temperate regions. © 2013, Springer-Verlag Berlin Heidelberg. Source

Huang L.,Chinese Academy of Agricultural Sciences | He H.,Chinese Academy of Agricultural Sciences | Chen W.,Chinese Academy of Agricultural Sciences | Ren X.,Chinese Academy of Agricultural Sciences | And 7 more authors.
Theoretical and Applied Genetics | Year: 2015

Key message: SSR-based QTL mapping provides useful information for map-based cloning of major QTLs and can be used to improve the agronomic and quality traits in cultivated peanut by marker-assisted selection. Abstract: Cultivated peanut (Arachis hypogaea L.) is an allotetraploid species (AABB, 2n = 4× = 40), valued for its edible oil and digestible protein. Linkage mapping has been successfully conducted for most crops, and it has been applied to detect the quantitative trait loci (QTLs) of biotic and abiotic traits in peanut. However, the genetic basis of agronomic and quality-related traits remains unclear. In this study, high levels of phenotypic variation, broad-sense heritability and significant correlations were observed for agronomic and quality-related traits in an F2:3 population. A genetic linkage map was constructed for cultivated peanut containing 470 simple sequence repeat (SSR) loci, with a total length of 1877.3 cM and average distance of 4.0 cM between flanking markers. For 10 agronomic traits, 24 QTLs were identified and each QTL explained 1.69–18.70 % of the phenotypic variance. For 8 quality-related traits, 12 QTLs were identified that explained 1.72–20.20 % of the phenotypic variance. Several QTLs for multiple traits were overlapped, reflecting the phenotypic correlation between these traits. The majority of QTLs exhibited obvious dominance or over-dominance effects on agronomic and quality traits, highlighting the importance of heterosis for breeding. A comparative analysis revealed genomic duplication and arrangement of peanut genome, which aids the assembly of scaffolds in genomic sequencing of Arachishypogaea. Our QTL analysis results enabled us to clearly understand the genetic base of agronomic and quality traits in cultivated peanut, further accelerating the progress of map-based cloning of major QTLs and marker-assisted selection in future breeding. © 2015, The Author(s). Source

Zheng Z.P.,Nanchong Academy of Agricultural science | Liu X.H.,China West Normal University
Genetics and Molecular Research | Year: 2013

Maize (Zea mays L.) is one of the most important cereal crops worldwide, and increasing the grain yield and biomass has been among the most important goals of maize production. The plant architecture can determine the grain yield and biomass to some extent; however, the genetic basis of the link between the plant architecture and grain yield/biomass is unclear. In this study, an immortal F9 recombinant inbred line population, derived from the cross Mo17 x Huangzao4, was used to detect quantitative trait loci (QTLs) for 3 traits associated with plant architecture under two nitrogen regimes: plant height, ear height, and leaf number. As a result, 8 and 10 QTLs were identified under the high nitrogen regime and low nitrogen regime, respectively. These QTLs mapped to chromosomes 1 (six QTLs), 2 (one QTL), 3 (one QTL), 7 (two QTLs), and 9 (eight QTLs), and had different genetic distances to their closest markers, ranging from 0 to 22.0 cM, explaining 4.7 to 20.5% of the phenotypic variance. Because of an additive effect, 9 and 9 could make the phenotypic values of traits increase and decrease to some extent, respectively. These results are beneficial for understanding the genetic basis of agronomic traits associated with plant architecture and for performing marker-assisted selection in maize breeding programs. © FUNPEC-RP. Source

Zheng Z.P.,Nanchong Academy of Agricultural science | Liu X.H.,China West Normal University
Genetics and Molecular Research | Year: 2013

The ear leaf is one of the most important leaves in maize (Zea mays); it affects plant morphology and yield. To better understand its genetic basis, we examined ear leaf length, ear leaf width, and ear leaf area for quantitative trait locus (QTL) mapping in a recombinant inbred line population under two nitrogen regimes. Nine QTLs, on chromosomes 1 (one), 2 (one), 3 (one), 4 (three), 7 (one), and 8 (two), were mapped under the high nitrogen regime, which explained phenotypic variation ranging from 5.4 to 14.8%. Under the low nitrogen regime, 7 QTLs were located on chromosomes 1 (one), 4 (two), 7 (one), and 8 (three), which accounted for phenotypic variation ranging from 5.5 to 20.5%. These QTLs had different mapping intervals to their nearest markers, ranging from 0.3 to 21.0 cM. Due to additive effects, 3 and 13 QTLs can cause phenotypic values of these traits to increase or decrease to some extent, respectively. This information will help understand the genetic basis of ear leaf formation and will be useful for developing marker-assisted selection in maize-breeding projects. © FUNPEC-RP. Source

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