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[学术文献 ] Fine mapping of a novel male-sterile mutant showing wrinkled-leaf in sesame by BSA-Seq technology 进入全文
Industrial Crops and Products
Genic male sterility (GMS) is a very important approach of heterosis exploitation in sesame (Sesamum indicum L.). Visible marker-trait linked to GMS is necessary since it can facilitate the breeding of new GMS lines and the production of F1 hybrid seeds. We have successfully developed such a GMS line showing wrinkled-leaf (JQA) from a mutant identified in a multiple-cross population in sesame. However, the underlying genetic basis for this JQA line is unclear. To understand the inheritance patterns, near-isogenic line (NIL) together with F2 and BC1 populations segregating for both pollen-fertility and leaf-shape was constructed. Morphology investigation indicated that the JQA line was controlled by a single recessive gene, Sims5. By combining bulk-segregant analysis and next-generation sequencing technology (BSA-Seq) in the NIL population, seven and four chromosome regions putatively associated with traits variation were identified by SNP and InDel markers, respectively. A 1,817.6-kb consensus region on chromosome 12 was obtained by intersecting these intervals, which was most likely the target region containing the candidate gene(s) responsible for pollen-fertility and leaf-shape. The consensus region was further narrowed down to only 219.7?kb by fine mapping in a BC1 population using SSR and InDel markers. Real-Time qRT-PCR analysis of genes within this region showed that four (XM_011097706.2, XM_011097714.2, XM_020698411.1 and XM_011097719.2) and one (XM_020698321.1) genes were highly suppressed in the anther and leaf of mutant plant, respectively, suggesting their important role in pollen and leaf development. These findings not only lay a solid foundation for the isolation and functional analysis of genes for pollen-fertility and wrinkled-leaf but also provided valuable genetic resources and molecular markers for the breeding of new sesame hybrid varieties.
[学术文献 ] Assessment of a stay-green mutant for variety improvement in Pakchoi (Brassica campestris L. ssp. chinensis) 进入全文
Scientia Horticulturae
Stay-green refers to a trait whereby plants retain greenness during senescence. In our previous study, a stay-green mutant of Pakchoi nye was screened out from an open pollinated strain and we found that the stay-green was controlled by a single recessive gene Brnye1. Bra019346 was identified as the candidate for Brnye1. The aim of this study was to evaluate the application of the stay-green lines for variety improvement in Pakchoi. The leaves of nye maintained greenness during senescence and the pigment content of nye was higher than that of wild type. No significant excessive accumulation of chlorophyll catabolites was observed in the chlorophyll catabolic pathway in nye during leaf senescence, which indicated no presence of dangerous phototoxic molecules. The net photosynthetic rate and the photochemical efficiency of photosystem II remained the same level as the wild type, which suggested that the photosystem functioned normally. In order to create more stay-green lines, the nye and a good line ‘13A510’ were used as parents to create a hybrid. The stay-green plants from the F2 were used as donor materials to conduct isolated microspore cultures and a total of 687 stay-green doubled haploid lines were obtained. In order to utilize heterosis, a stay-green cytoplasmic male sterile line CMS-nye was created through backcrossing to a cytoplasmic male sterile line by using nye as recurrent parent. Storage experiment indicated that the stay-green Pakchoi could prolong shelf life and improve the quality of commodity. These results lay the foundation for application of the stay-green genetic resource for variety improvement in Pakchoi.
[学术文献 ] Comparative Transcriptome Analysis between Cytoplasmic Male-sterile Line and Its Maintainer During the Floral Bud Development of Pepper 进入全文
Horticultural Plant Journal
The male-sterile line has been largely used in the hybrid seed production of pepper, which can effectively improve the efficiency of hybrid seed production. However, the formation mechanism of male sterility in pepper remains unclear. In the present study, we compared the gene expression patterns between pepper cytoplasmic male sterile line 9704A and its maintainer 9704B during floral bud development using RNA sequencing technology. A total of 547 976 and 2 416 Differentially Expressed Genes (DEGs) were identified in the stage S1, S2 and S3, respectively, and more than 70% of the DEGs were down-regulated in the sterile line. Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to further understand the functions of these identified DEGs. The results showed that the DEGs were mainly enriched in pathways of starch and sucrose metabolism, pentose and glucuronate interconversions. A number of genes, such as MS1, PME5, ATPB, and lots of transcription factors were found down-regulated in the sterile line, and we also identified a series of genes with large differences in expression patterns between sterile line and maintainer line. Collectively, our findings laid a foundation for further molecular breeding in pepper and provided new insights into its mechanism underlying the male sterility.
[学术文献 ] A HAK family Na+ transporter confers natural variation of salt tolerance in maize 进入全文
Nature Plants
Excessive sodium ion (Na+) concentrations in cultivated land alter crop yield and quality worldwide. Previous studies have shown that shoot Na+ exclusion is essential in most crops for salt tolerance. Here, we show by a genome-wide association study that Zea may L. Na+ content 2 (ZmNC2), encoding the HAK family ion transporter ZmHAK4, confers the natural variation of shoot Na+ exclusion and salt tolerance in maize. The ZmHAK4 locus accounts for ~11% of the shoot Na+ variation, and a natural ZmHAK4-deficient allele displays a decreased ZmHAK4 expression level and an increased shoot Na+ content. ZmHAK4 is preferentially expressed in the root stele and encodes a novel membrane-localized Na+-selective transporter that mediates shoot Na+ exclusion, probably by retrieving Na+ from xylem sap. ZmHAK4 orthologues were identified in other plant species, and the orthologues of ZmHAK4 in rice and wheat show identical expression patterns and ion transport properties, suggesting that ZmHAK4 orthologues mediate an evolutionarily conserved salt-tolerance mechanism. Finally, we show that ZmHAK4 and ZmHKT1 (a HKT1 family Na+-selective transporter) confer distinct roles in promoting shoot Na+ exclusion and salt tolerance, indicating that the combination of the favourable alleles of ZmHKT1 and ZmHAK4 can facilitate the development of salt-tolerant maize varieties.
[学术文献 ] Accession difference in leaf photosynthesis, root hydraulic conductance and gene expression of root aquaporins under salt stress in barley seedlings 进入全文
Plant Production Science
Soil salinity causes considerable losses of crop productivity. Barley (Hordeum vulgare) is one of the most salt-tolerant Gramineae crops. Previously, we found that net photosynthetic rate (A n) was kept remarkably higher in the salt-tolerant barley accession OUE812 than in the salt-sensitive accession OUC613 after heading under salt stress due to the low level of salt accumulation in leaves. Here we grew seedlings in Hoagland solution with 100 mM NaCl (salt treatment) or without added NaCl (control), and compared A n, stomatal conductance (g s), salt accumulation in leaves, root hydraulic conductance and gene expression of root aquaporins between the accessions under salt stress for a few days. A n, g s and root hydraulic conductance of the plants with salt treatment decreased significantly in OUC613 compared to OUE812 with no accession difference in salt accumulation in leaves at 2 days after the onset of treatment (DAT). The reduction in root hydraulic conductance in OUC613 was caused by the reduction of the root hydraulic conductivity (Lp r). Salt treatment also decreased the transcript levels of some plasma membrane intrinsic aquaporin genes (HvPIPs) in OUC613 and, on the contrary, increased those of some HvPIPs in OUE812, resulting in a large difference between OUC613 and OUE812 in the transcript levels at 2 DAT. The accession difference in HvPIPs expression and thus Lp r was closely associated with the accession difference in A n and g s under the short-term salt stress.
[学术文献 ] Different lengths, copies and expression levels of the mitochondrial atp6 gene in male sterile and fertile lines of carrot (Daucus carota L.) 进入全文
Mitochondrial DNA Part A
The male-sterile carrot is an effective material for carrot breeding. The atp6 gene is involved in carrot fertility. However, the differences in lengths, copies, and expression profiles of the atp6 gene in fertile and male-sterile lines of carrot are unclear. In this study, one copy atp6 gene was found in the mtDNAs of ‘Kuroda’ (fertility, 954?bp) and ‘Wuye-BY’ (male sterility, 819?bp) carrot lines, while two copies atp6 genes (Wuye-L and Wuye-D, 954?bp and 819?bp, respectively) were found in the mtDNA of ‘Wuye’ (fertility). Two putative conserved domains have been detected in the carrot atp6 protein. Evolutionary analysis showed that the atp6 protein sequences of Wuye-L and Kuroda were clustered in the same branch, while Wuye-D and Wuye-BY were clustered in the same branch. The atp6 gene was higher expressed in the flowers of ‘Kuroda’ and ‘Wuye’ (Wuye-L), while lower expressed in ‘Wuye-BY’ and ‘Wuye’ (Wuye-D).
