[Objective] Fluorescence in situ hybridization (FISH) can achieve the accurate chromosomal localization of DNA sequences, which is one of the important techniques for genome in-depth study. The acquisition of chromosome-specific probes is the key for FISH application. The aim of this study is to explore a system of cotton oligonucleotides (oligos) fluorescence in situ hybridization (Oligo-FISH) technology. [Method] Based on the published cotton genome sequence, the chromosome-specific oligos library was obtained by bioinformatics method. Then, the obtained oligos were labeled through emulsion polymerase chain reaction, and used for FISH of cotton mitotic chromosome. [Results] A system of cotton Oligo-FISH technology was set up and successfully applied in cotton chromosome identification. [Conclusion] This system can be used for dissection of cotton genomes.
[Objective] The KFB (Kelch containing F-box protein) family, involving in many physiological pathways, is a subfamily of the biggest F-box protein family in all organisms. In the study, we aims to identify the KFB family members in the upland cotton genome and analyze their expression patterns. [Method] The KFB genes were identified from the whole genome of upland cotton (Gossypium hirsutum L. acc. TM-1) by bioinformatics methods. A phylogenetic analysis was conducted based on the alignment of the KFB proteins from upland cotton, Arabidopsis, rice and soybean, and the gene structure, chromosomal localization, and expression of subgroup Ⅱ in this family. [Result] A total of 150 KFB genes were identified from the whole genome of upland cotton and were then divided into seven subgroups based on phylogenetic analyses. In subgroup Ⅱ, 24 genes distributed on fourteen chromosomes, and nine pairs were orthologous genes. Structures of half genes in this subfamily were simple, including only one exon, respectively. According to the results of qRT-PCR, this subfamily had a wide range of tissue expression patterns, but the expression level of these genes varied from different tissues. [Conclusion] The results indicate that the functions of subgroup Ⅱ in KFB family have been differentiated during the process of evolution.
[Objective] The aim of this study was to map quantitative trait loci (QTL) of yield-related traits in cotton. [Method] The F2 segregation population of upland cotton hybrid CCRI 70 was used. We used a total of 14 820 simple sequence repeats (SSR) primer pairs to screen the polymorphism between the parents (sGK156 and 901-001) of CCRI 70, and 267 polymorphic primer pairs were obtained. We used these polymorphic primers to identify the 250 individual plants of F2 population derived from CCRI 70, Joinmap 4.0 for linkage analysis, and composite interval mapping in WinQTLCart 2.5 to detect QTL of three traits (plant height, fruit branch number and boll number) in the 250 F2:3 family lines. [Result] In the F2 population, we obtained 342 loci, and constructed a genetic linkage map covering 1 929.9 cM (accounting for 43.4% of the cotton genome), with 312 SSR loci, 35 linkage groups and an average interval of 9.2 cM between two neighbour markers. By QTL analysis on three traits of the 250 F2:3 family lines, we identified 19 QTL, explaining 0.25%-11.28% of phenotypic variation, including 7 QTLs for plant height, 4 for fruit branch number, and 8 for boll number, which locates on 8 chromosomes. [Conclusion] These results may help for breeding programs involved in marker-assisted development of new cultivars with improved yield.
[Objective] The aims of this study are to detect drought tolerance of upland cotton (Gossypium hirsutum L.), to find the molecular markers associated with the drought tolerance traits, and to excavate elite allelic variation associated with drought resistance traits. [Method] We selected 191 cultivars (lines) as experimental materials. The germination rates during sprouting period were evaluated in 15% (mass fraction) PEG6000 stress. Drought tolerance was classified according to the membership function values to drought resistance at sprouting period. A total of 74 pairs of simple sequence repeat (SSR) primers were employed to detect the genomic variation of the natural population. Based on the analysis of the genetic structure of the natural population using Structure 2.3.4, the GLM model of Tassel 2.0 was used to correlate the genotype data with the drought tolerance traits at germination stage to find the molecular markers associated with the drought tolerance traits. [Result] A total of 46 high-resistance materials, 59 medium-drought resistant materials and 86 drought-sensitive materials were identified; population structure analysis divided the 191 materials into two subgroups, consisting of 123 and 68 materials, respectively; the association analysis showed that 15 SSR sites related to drought resistance at germination stage (P < 0.05), explained phenotypic variation ranged from 2.2% to 7.49%. [Conclusion] We screened out 46 drought-resistant materials and 15 molecular markers related to drought tolerance, which may be used for cotton drought-resistant marker-assisted breeding.
[Objective] The aim of this study is to mine pathogenesis related genes of Verticillium dahliae. [Method] We explored the transcriptome of highly toxic V. dahliae strain Vd991 at the early stage of infection in Coker 312, an upland cotton cultivar. [Result] Through differential expression analysis, a total of 979 differentially expressed genes (DEGs）were identified after infection, of which 376 were up-regulated and 603 were down-regulated. The result of gene annotation and classification showed that these DEGs are involved in broad biological processes, molecular function and cellular component, including reproductive process, growth, sporulation, carbohydrate binding, kinase regulator activity, lyase activity and hydrolase activity. Enrichment analysis of the up-regulated DEGs were performed, 277 gene ontology terms were enriched, including positive regulation of growth rate, purine nucleotide biosynthetic process, pyrimidine nucleobase biosynthetic process, helicase activity. A total of 53 Kyoto Encyclopedia of Genes and Genomes pathways were identified in the up-regulated DEGs, including purine metabolism, pyrimidine metabolism. [Conclusion] These results indicate that genes related to cell proliferation actively expressed at the early stage of infection and provide valuable reference for exploring the pathogenic mechanism of V. dahliae.
[Objective] To investigate the correlation between seed fuzz amount and fiber quality of sea-island cotton and to improve its quality breeding efficiency. [Method] 218 germplasm resources of sea-island cotton were used as tested materials, through two-year detection of its fiber quality traits, investigation and classification of the fuzz. The difference of fiber quality traits of sea-island cotton among each fuzz grade and correlation between amount of seed fuzz and fiber quality of sea-island cotton were analyzed. [Result] Variance analysis showed that other fiber quality traits among different grades increased extremely significant (P < 0.01) or significant (P < 0.05) with fuzz grade (fuzz density) increasing except micronaire. Spearman rank correlation coefficients indicated that upper half mean length, breaking tenacity, uniformity index and breaking elongation were significantly and positively correlated (P < 0.01) with fuzz grades respectively, while micronaire was significantly and negatively correlated (P < 0.05) with fuzz grades. [Conclusion] These results indicate that there is a statistically positive correlation between seed fuzz amount and fiber quality of sea-island cotton (G. barbadense), the seed fuzz amount can be used as a standard for the fiber quality pros and cons of sea-island cotton.
[Objective] Cotton seedlings are predisposed to chilling injury, and proper low-temperature pretreatment may improve the cold tolerance. The aim of this study is to analyze the effects of 12 ℃ cold acclimation to 4 ℃ cold tolerance by observing the leaf cell ultrastructure of Jinmian 49 and Keneng 0518 cotton seedlings. [Method] Cotton seeds of the two varieties were delinted and soaked for appropriate time, then cultured at 28 ℃/12 h lighting condition. At stage of euphylla, half of the seedlings were placed at 12 ℃/12 h lighting acclimation for 5 days, leaving the others as control (non-cold acclimation); Then all placed at 4 ℃/12 h lighting treatment for 5 days, and leaf cell ultrastructure were observed and compared. [Result] In the 4 ℃ cold tolerance process, Jinmian 49 and Keneng 0518 with cold acclimation at 12 ℃ for 5 days kept better chloroplast, accumulated starch grain and high electron absorbing material; Keneng 0518 also kept integrated nucleus membrane, congregated arrangement of mitochondrion, tubular or bubbly endoplasmic reticulum. [Conclusion] These results indicated that cotton seedlings could adapt to 4 ℃ cold tolerance through better chloroplast, accumulating starch grain and high electron absorbing material after 12 ℃ cold acclimation.
[Object] This paper focused on interaction patterns between trial environments and cotton fiber quality performance. [Method] We analyzed the cotton fiber quality distribution characteristics by using the data sets of national cotton regional trials during 2005―2014. Environmental samples were focused on 19 test locations of medium-maturing and conventional cotton varieties in the Yellow River valley. Cotton fiber quality performance and environment interaction patterns based on the selection fiber quality breeding traits, the correlation between spinning consistency index and fiber traits were explored with GGE biplot method to analyze the potential ecological sub-regions. [Result] (1) The significant correlations were found among fiber spinning consistency index, fiber length, strength and uniformity index, and micronaire was significantly related with elongation negatively, while no significant relationships among other traits were detected. (2) The target cotton planting region in the Yellow River valley could be divided into three subregions in terms of cotton fiber quality in the nineteen ecological trials. The ecological subregion Ⅰ including Siyang and Xiangshui of Jiangsu, Lingbi of Anhui, and Xinxiang and Shangqiu of Henan was characterized by best performances of fiber upper half mean length, breaking strength, uniformity and spinning consistency index, in which fiber index were all significantly superior than those of the other two subregions, while fiber uniformity index was significantly higher than that of the subregion Ⅲ. Generally speaking, fiber upper half mean length, breaking strength and micronaire were developed harmoniously and all reached the class Ⅱ level of national cotton registration standard in the subregionⅠ, which was named as "super quality ecological regions". The subregion Ⅱ covering Dali of Shaanxi, Xihua of Henan, Shijiazhuang and Gucheng of Hebei, and Ningjin of Shandong was characterized by relative higher micronaire, moderate performances of fiber length and strength, relative poor spinning consistency index, so named as "moderate fiber ecological region". The subregion Ⅲ containing Yangling of Shaanxi, Yuncheng of Shanxi, Anyang of Henan, Handan and Cangzhou of Hebei, Ninghe of Tianjin, and Huimin, Jinxiang and Linqing of Shandong was characterized by lower micronaire and moderate performances of other fiber traits, could be called as "low micronaire ecological region". [Conclusion] This study helps to definite ecological region of cotton fiber quality in the Yellow River valley, and can provide foundations for the selection of cotton varieties, ecological division and ideal test environment selection in the Yellow River valley.
[Object] To understand the variation of the response of root morphology and phosphatase activity of two cotton varieties to five phosphorus supply levels. [Method] A high phosphorus efficient variety Xinluzao 19 and a low phosphorus efficient variety Xinluzao 13 were selected as testing plants, through comparing the changes of biomass, phosphorus content, root morphology and phosphatase activity at different phosphorus supply levels in nutrient solution culture. [Result] When phosphorus supply was higher than 50 μmol·L-1, the increase of phosphorus supply will not improve biomass and root length anymore. The activity of phosphatase on cotton root surface decreased sharply with the increase of phosphorus supply, the activity of acid phosphatase at actual pH was negatively correlated with plant phosphorus concentration. The response of root morphology to phosphorus supply was not sensitive, there was a significant difference only under the conditions between treatment of no phosphorus and those of phosphorus supply. When phosphorus supply was 0~250 μmol·L-1, the P utilization efficiency of Xinluzao 19 was significantly higher than that of Xinluzao 13. [Conclusion] It can be considered that the response of cotton root morphology characteristic parameters and the quantity of the root release of protons and organic acids to phosphorus supply is not sensitive. This provided a very effective experimental material on saving phosphorus and increasing its efficiency of the biological potential and regulation pathway of cotton with phosphorus utilization efficiency genotypes discovered.
[Objective] The objective of this research is to study the host choice behavior of cotton and cucumber biotype aphid depending on taste and the choice mechanism. [Method] Host choice experiments of the two host biotypes were conducted by the method of Petri dish. The metabolites of cotton, cucumber and zucchini leaf in the seedling stage were measured using gas chromatography/time-of-flight mass spectrometry (GC-TOFMS) and the differential secondary compounds were selected. [Result] The experiments of behavior choice showed that the two host biotypes had a significantly higher choice to their native host, respectively, and there was no significant difference to zucchini host. There was a big difference in the content of secondary compounds among cotton, cucumber and zucchini. The relative contents of succinic acid and putrescine were 0.8006 and 0.2409 in the leaves of cotton, and 0.1960 and 0.4401 in cucumber, respectively. [Conclusion] The host choice of cotton aphid experienced the initial olfactory response and completed the recognition of taste, which could reflect the influence of secondary compounds to the host choice of cotton aphid. It is speculated that differential secondary compounds may influence the host choice of different host biotype aphid.
Gossypol is the important restriction factor of the development and utilization of cottonseed. The key to solve this problem is cultivating glandless cotton, especially by genetic engineering. The research on the genes of gossypol biosynthesis and cotton gland formation is the basis of cultivating glandless cotton by genetic engineering. We reviewed the domestic and abroad research progress on the genes of gossypol biosynthesis and cotton gland formation and the related example of breeding the glandless cotton by genetic engineering, in order to provide references for the related researchers.
