Upland cotton is the most important natural-fiber crop. The genomic variation of diverse germplasms and alleles underpinning fiber quality and yield should be extensively explored. Here, we resequenced a core collection comprising 419 accessions with 6.55-fold coverage depth and identified approximately 3.66 million SNPs for evaluating the genomic variation. We performed phenotyping across 12 environments and conducted genome-wide association study of 13 fiber-related traits. 7,383 unique SNPs were significantly associated with these traits and were located within or near 4,820 genes; more associated loci were detected for fiber quality than fiber yield, and more fiber genes were detected in the D than the A subgenome. Several previously undescribed causal genes for days to flowering, fiber length, and fiber strength were identified. Phenotypic selection for these traits increased the frequency of elite alleles during domestication and breeding. These results provide targets for molecular selection and genetic manipulation in cotton improvement.

Cotton is an important fiber crop worldwide. Improved fiber quality is a driving force for cotton genetic studies and breeding. A BC 1 population containing 115 individuals from a cross between Gossypium hirsutum cv. CCRI8 and G. barbadense cv. Pima 90-53 was established, and 519 simple sequence repeat (SSR) markers, two conserved intronscanning primers (CISPs), and transcript-derived fragments (TDFs) amplified from 156 ApoI/TaqI selective primer combinations were used to construct a genetic linkage map. The map included 579 markers distributed on 56 linkage groups. Accounting for 83.4 % of the cotton genome, it covered 4,168.72 cM, with an average distance of 7.19 cM between markers. Lengths of the linkage groups ranged from 1.25 to 255.79 cM, with 2 to 44 markers per group. Of these 56 groups, 43 were assigned to 26 chromosomes, with the remaining 13 unknown. Based on this newly constructed map of tetraploid cotton, we performed quantitative trait loci (QTL) mapping and analysis of fiber quality traits from the BC 1 and its derived BC 1 F 2 lines. A total of 44 fiber quality QTL were detected on 17 chromosomes, explaining 7.72-23.73 % of the phenotypic variation. Pima 90-53 offered 13 QTL alleles with positive additive effects and four with negative additive effects for fiber quality traits. The results from this study may provide useful information for breeders to transfer desirable fiber traits from cotton types, such as the Sea Island strain, to Upland cotton that is primarily cultivated currently.

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Background: Glioblastoma (GBM), a malignant grade IV tumor, is the most malignant brain tumor due to its hyper-proliferative and apoptosis-evading characteristics. The signal transducer and activators of transcription (STAT) family genes, including STAT3 and STAT5A, have been indicated to play important roles in GBM progression. Increasing number of reports suggest that garcinol, a polyisoprenylated benzophenone and major bioactive component of Garcinia indica contains potent anti-cancer activities. Material and Methods: The present study investigated the anti-GBM effects of garcinol, focusing on the STAT3/STAT5A activation, using a combination of bioinformatics, in vitro, and ex vivo assays. Results: Our bioinformatics analysis of The Cancer Genome Atlas (TCGA)–GBM cohort (n = 173) showed that STAT3 and STAT5A are preferentially elevated in primary and recurrent GBM, compared to non-tumor brain tissues, and is significantly correlated with reduced overall survival. In support, our immunohistochemical staining of a GBM cohort (n = 45) showed an estimated 5.3-fold (p < 0.001) elevation in STAT3 and STAT5A protein expression in primary and recurrent GBM versus the non-tumor group. In vitro, garcinol treatment significantly suppressed the proliferative, invasive, and migratory potential of U87MG or GBM8401 cells, dose-dependently. In addition, garcinol anticancer effect significantly attenuated the GBM stem cell-like phenotypes, as reflected by diminished ability of U87MG or GBM8401 to form colonies and tumorspheres and suppressed expression of OCT4 and SOX2. Furthermore, analysis on GBM transcriptome revealed an inverse correlation between the level of STAT3/5A and hsa-miR-181d. Garcinol-mediated anti-GBM effects were associated with an increased hsa-miR-181d/STAT3 and hsa-miR-181d/5A ratio. The results were further verified in vivo using U87MG mouse xenograft model where administration of garcinol significantly inhibited tumor growth. Conclusions: We present evidence of anti-GBM efficacy of garcinol mediated by enhancing the hsa-miR-181d/STAT3 and hsa-miR-181d/5A ratios in GBM cells. Our findings suggest a potential new therapeutic agent for combating aggressive GBM.

UDP-xylose (UDP-Xyl) is a nucleotide sugar used as substrate for producing non-cellulose materials, e. g., hemicellulose and pectic polysaccharide, in the fibers of cotton (Gossypium). Its biosynthesis is catalyzed from UDP-glucuronic acid (UDP-GlcA) by UDP-glucuronate decarboxylase (UXS). Here, we first cloned GhUXS1 in Gossypium hirsutum and Gossypium barbadense based on a transcript-derived fragment that originated from our cDNA-AFLP transcriptome profiling in cotton. GhUXS2 and GhUXS3 were also isolated via homology-based cloning. GhUXS nucleotide sequences were identical between the two species, and the deduced amino acid residues had the conserved motif of the UXS family, i.e., GxxGxxG, Ser residues, and YxxxK. GhUXS1 was expressed in Escherichia coli and generated UXS activity that converted UDP-GlcA to UDP-Xyl. Semiquantitative RT-PCR results showed that GhUXSs transcripts were preferentially expressed during fiber development, from elongation through the stage of secondary cell wall synthesis. Although at the same number of days postanthesis they were more abundant in G. hirsutum, expression was sustained for a longer period in G. barbadense. These different patterns of expression may affect quality and partially explain why the latter species has better fiber strength.

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Fasciclin-like arabinogalactan (FLA) protein is a cell-wall-associated protein playing crucial roles in regulating plant growth and development, and it was characterized in different plants including Upland cotton (Gossypium hirsutum L.). In cDNA-AFLP analysis of 25 DPA (days post anthesis) fiber mRNA, two FLA gene-related transcripts exhibit differential expression between Sea Island cotton ( G . barbadense L.) and Upland cotton. Based on the transcript-derived fragment, RACE-PCR and realtime PCR technique, GbFLA5 full-length cDNA was isolated and its expression profiles were characterized in both cotton plant tissues and secondary cell wall (SCW) fibers in this study. The 1154 bp GbFLA5 cDNA contains an ORF of 720 bp, encoding GbFLA5 protein of 239 amino acids residues in length with an estimated molecular mass of 25.41 kDa and isoelectric point of 8.63. The deduced GbFLA5 protein contains an N-terminal signal sequence, two AGP-like domains, a single fasciclin-like domain, and a GPI anchor signal sequence. Phylogenetic analysis shows that GbFLA5 protein is homologous to some known SCW-specific expressed FLAs of plant developing xylem, tension wood and cotton fibers. In the SCW deposition stage from 15 to 45 DPA detected, FLA5 maintains a significantly higher expression level in Sea Island cotton fibers than in Upland cotton fibers. The increasing FLA5 transcript abundance coincided with the SCW deposition process and the expression intensity differences coincided with their fiber strength differences between Sea Island cotton and Upland cotton. These expression profile features of GbFLA5 in cotton fibers revealed its tissue-specific and SCW developmental stage-specific expression characters. Further analysis suggested that GbFLA5 is a crucial SCW-specific protein which may contribute to fiber strength by affecting cellulose synthesis and microfibril deposition orientation.