Cotton Fiber Length Research Articles

Low soil available phosphorus level reduces cotton fiber length via osmoregulation.

Phosphorus (P) deficiency hinders cotton (Gossypium hirustum L.) growth and development, seriously affecting lint yield and fiber quality. However, it is still unclear how P fertilizer affects fiber length. Therefore, a two-year (2019-2020) pool-culture experiment was conducted using the split-plot design, with two cotton cultivars (CCRI-79; low-P tolerant and SCRC-28; low-P sensitive) as the main plot. Three soil available phosphorus (AP) contents (P0: 3 ± 0.5, P1: 6 ± 0.5, and P2 (control) with 15 ± 0.5 mg kg-1) were applied to the plots, as the subplot, to investigate the impact of soil AP content on cotton fiber elongation and length. Low soil AP (P0 and P1) decreased the contents of the osmotically active solutes in the cotton fibers, including potassium ions (K+), malate, soluble sugar, and sucrose, by 2.2-10.2%, 14.4-47.3%, 8.7-24.5%, and 10.1-23.4%, respectively, inhibiting the vacuoles from facilitating fiber elongation through osmoregulation. Moreover, soil AP deficiency also reduced the activities of enzymes participated in fiber elongation (plasma membrane H+-ATPase (PM-H+-ATPase), vacuole membrane H+-ATPase (V-H+-ATPase), vacuole membrane H+-translocating inorganic pyrophosphatase (V-H+-PPase), and phosphoenolpyruvate carboxylase (PEPC)). The PM-H+-ATPase, V-H+-ATPase, V-H+-PPase, and PEPC were reduced by 8.4-33.0%, 7.0-33.8%, 14.1-38.4%, and 16.9-40.2%, respectively, inhibiting the transmembrane transport of the osmotically active solutes and acidified conditions for fiber cell wall, thus limiting the fiber elongation. Similarly, soil AP deficiency reduced the fiber length by 0.6-3.0 mm, mainly due to the 3.8-16.3% reduction of the maximum velocity of fiber elongation (VLmax). Additionally, the upper fruiting branch positions (FB10-11) had higher VLmax and longer fiber lengths under low soil AP. Cotton fibers with higher malate content and V-H+-ATPase and V-H+-PPase activities yielded longer fibers. And the malate and soluble sugar contents and V-H+-ATPase and PEPC activities in the SCRC-28's fiber were more sensitive to soil AP deficiency in contrast to those of CCRI-79, possibly explaining the SCRC-28 fiber length sensitivity to low soil AP.

Reflectivity and fluffiness coupled optical algorithm for colored cotton fibrogram of random-beard image method

Insufficient studies of reflectance and fluffiness effects on optical density caused large derivation and limited the application of fibrogram methods in colored cotton fiber length tests for decades. A coupled optical method was proposed here to solve this issue, named reflectivity and fluffiness coupled optical algorithm of the random-beard image method. In this algorithm, a defined theoretical reflectance was declared with an iteration method for optical linear density on the optical analysis of the derived Kubelka–Munk law, which satisfied its assumption of excluding reflected light at the interface with air. Meanwhile, an apparent polynomial relationship was revealed between the actual density and optical densities of fiber assemblies at different fluffiness. Its accuracy on weighted mean fiber length was demonstrated, referred to as advanced fiber information system, using 10 kinds of dyed cotton slivers and 12 kinds of naturally colored lint fibers whose mean and maximum absolute errors are 0.59 mm and 1.6 mm, respectively. Furthermore, their excellent agreement on fibrograms and the weighted mean length was confirmed by Bland–Altman analysis, correlation analysis and the T-test. Finally, an exceptionally high linear correlation (r2 = 0.93) was achieved on their weighted mean length and had no statistical difference with insignificant deviation under a significance level of a = 0.01. This new algorithm, featured fast and low cost, could provide accurate mean fiber length of colored or dark cotton, exhibiting valuable guidance in the potential application of the fiber trade and the quality control of colored cotton fibers or primaries in blending assemblies and yarn.

Characterization of chromatin accessibility and gene expression reveal the key genes involved in cotton fiber elongation.

Cotton (Gossypium hirsutum L.) is an important economic crop, and cotton fiber is one of the longest plant cells, which provides an ideal model for the study of cell elongation and secondary cell wall synthesis. Cotton fiber length is regulated by a variety of transcription factors (TF) and their target genes; however, the mechanism of fiber elongation mediated by transcriptional regulatory networks is still unclear to a large extent. Here, we used a comparative assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) assay and RNA-seq analysis to identify fiber elongation transcription factors and genes using the short-fiber mutant ligon linless-2 (Li2 ) and wild type (WT). A total of 499 differential target genes were identified and GO analysis shows that differential genes are mainly involved in plant secondary wall synthesis and microtubule-binding processes. Analysis of the genomic regions preferentially accessible (Peak) has identified a number of overrepresented TF-binding motifs, highlighting sets of TFs that are important for cotton fiber development. Using ATAC-seq and RNA-seq data, we have constructed a functional regulatory network of each TF regulatory target gene and also the network pattern of TF regulating differential target genes. Further, to obtain the genes related to fiber length, the differential target genes were combined with FLGWAS data to identify the genes highly related to fiber length. Our work provides new insights into cotton fiber elongation.

Yield and Fiber Quality Balance in Upland Cotton (Gossypium Hirsutum L.) Breeding

The main aim of cotton breeding is to combine yield and fiber quality by broadening the genetic base of the genotypes. The performance of multi-parent hybrid populations and the association among yield attributes and quality parameters were investigated by biometrical techniques, i.e., principal component analysis (PCA), correlation analysis and decision tree. The mean and range of crosses were higher for seed cotton yield and ginning out-turn; similar for fiber strength and length; coarse for fiber fineness compared to their parents. Significantly negative correlations were recorded between seed cotton yield and fiber length; ginning out-turn and fiber fineness. PCA analysis indicated that fiber fineness and ginning out-turn were on the same platform, whereas seed cotton yield per plant with fiber length and fiber fineness were on opposite platforms. The decision tree model showed that fiber fineness (4.60 mic.) within commercial limits depends on the optimization of seed cotton yield per plant of approximately 54.27 g and ginning out-turn of 42.60% in single plant selection. Bangladesh J. Bot. 52(2): 283-290, 2023 (June)

A New Method to Calculate Cotton Fiber Length Uniformity Using the HVI Fibrogram

Knowledge of cotton fiber length uniformity is important for the cotton industry. The accurate and reliable measurement of fiber length uniformity would allow cotton breeders to release new cotton varieties with improved fiber length variation. This knowledge would also help spinning mills to optimize their machine setup, which would improve yarn processing performance. Currently, the high volume instrument (HVI) is most commonly used to characterize the cotton fiber length variation. The HVI length measurement is based on the fibrogram principle. The HVI length measurement characterizes 2 points, 1.8% as the upper half mean length (UHML) and 7.8% span length as the mean length (ML) from the fibrogram, and reports UHML and uniformity index (UI). The ratio of ML to the UHML is used to calculate the UI and is expressed as a percentage. UI measurement does not represent the shorter fibers as the above two span lengths only represent the longest fibers within a sample. We propose to calculate the uniformity of the cotton fiber length using the complete fibrogram as an alternative. First, the area of the measured fibrogram curve is calculated. Second, the area of a theoretical mono-length fibrogram with a length equal to the maximum length of the fibers for the same sample is calculated. Finally, we calculate a new length uniformity as the ratio of the measured fibrogram area to the mono-length fibrogram area expressed as a percentage. Based on the results obtained using a set of 991 commercial samples, the new length uniformity shows promise. We also applied this new length uniformity to a set of 60 commercial-like samples and developed partial least square regression (PLSR) prediction models to predict yarn quality. The results obtained demonstrate that the new length uniformity predicts yarn quality better than the current UI.

Drought shortens cotton fiber length by inhibiting biosynthesis, remodeling and loosening of the primary cell wall

Drought could severely impair the formation of cotton fiber length, yet the underlying mechanism is not fully understood. Here, the effects of drought on cotton fiber elongation processes including primary cell wall biosynthesis, remodeling and loosening and osmolyte accumulation were investigated from transcriptomic and physiological levels by using two upland cotton cultivars (Dexiamian 1 and Yuzaomian 9110). The results showed that the cotton fiber elongation was significantly stunted under drought, and the biggest reduction in fiber length appeared at 10 days post anthesis. The total osmolytes concentration of cotton fiber sap was increased by drought via promoting the accumulation of malate and K+, which was favorable to fiber elongation. Whilst the biosynthesis of fiber primary cell wall components including pectin, hemicellulose and cellulose was inhibited under drought by suppressing the expression of galacturonosyltransferase (GhGAUT) and galacturonosyltransferase-like (GhGATL), xylosyltransferase (GhXXT), and cellulose synthase (GhCesA) respectively, leading to reduced fiber cell wall biomass. Meanwhile, drought restricted the remodeling and loosening of fiber primary cell wall by suppressing the expression of genes related to primary cell wall decomposition including pectin methylesterase (GhPME), xyloglucan endotransglucosylase/hydrolase (GhXTH), and endoglucanase (GhEG), and α-expansin (GhEXPA). Taken together, it is concluded that the shortened fiber length induced by drought was caused by restricted primary fiber cell wall biosynthesis, remodeling, and loosening but not the lowered osmotic potential. Overall, our work provides new insights into understanding the mechanisms by which drought shortens cotton fiber length.

Nano-silicon and boron foliar applications for promoting growth, yield, and fiber quality of Egyptian cotton (Gossypium barbadense L.)

Improving cotton yield and fiber quality is a necessity to supply the increasing demand for natural fibers manufacturing. Therefore, this study aims to evaluate nano-silicon (Si) and boron (B) foliar applications on growth, yield and fiber quality of Egyptian cotton cultivars (Giza 92, 94, and 95). Field experiments were conducted in the Agricultural Research and Experimental Station, Faculty of Agriculture, Cairo University, Egypt during seasons of 2019 and 2020. The experiments were laid out in a split-plot based on a Randomized Complete Block Design with five replicates. Six foliar applications (control, convention-Si, nano-Si, B, convention-Si + B, and nano-Si + B) were performed three times (45, 65, and 80 days after sowing). Results showed the superiority of Giza 95 in total and open bolls plant−1, boll weight, lint% and seed cotton yield, Giza 92 in plant height, sympodial branches plant−1 and fiber quality, while Giza 94 in seed index and color attributes. Individual nano-Si was superior in plant height (119.8 cm), boll weight (2.42 g), lint% (38.8%), seed cotton yield (40.26 g plant−1 and 3670 kg ha−1), uniformity index (85.85%), while individual B was superior in total (23.14) and open (19.91) bolls/plant. Individual Si or B had an equivalent effect on seed index, fiber length, strength and color attributes. compared with convention-Si + B, Nano-Si + B significantly increased plant height (3.42%), total (5.34%) and open (4.44%) bolls plant−1, boll weight (3.21%), lint% (1.82%), uniformity index (1.41%) while insignificantly differed in seed cotton yield, fiber length and strength. Therefore, nano-Si + B foliar applications are recommended to improve cotton production and fiber quality.

Phenomics and transcriptomics analyses reveal deposition of suberin and lignin in the short fiber cell walls produced from a wild cotton species and two mutants.

Fiber length is one of the major properties determining the quality and commercial value of cotton. To understand the mechanisms regulating fiber length, genetic variations of cotton species and mutants producing short fibers have been compared with cultivated cottons generating long and normal fibers. However, their phenomic variation other than fiber length has not been well characterized. Therefore, we compared physical and chemical properties of the short fibers with the long fibers. Fiber characteristics were compared in two sets: 1) wild diploid Gossypium raimondii Ulbrich (short fibers) with cultivated diploid G. arboreum L and tetraploid G. hirsutum L. (long fibers); 2) G. hirsutum short fiber mutants, Ligon-lintless 1 (Li1) and 2 (Li2) with their near isogenic line (NIL), DP-5690 (long fibers). Chemical analyses showed that the short fibers commonly consisted of greater non-cellulosic components, including lignin and suberin, than the long fibers. Transcriptomic analyses also identified up-regulation of the genes related to suberin and lignin biosynthesis in the short fibers. Our results may provide insight on how high levels of suberin and lignin in cell walls can affect cotton fiber length. The approaches combining phenomic and transcriptomic analyses of multiple sets of cotton fibers sharing a common phenotype would facilitate identifying genes and common pathways that significantly influence cotton fiber properties.

Fine mapping and candidate gene analysis of qFL-A12-5: a fiber length-related QTL introgressed from Gossypium barbadense into Gossypium hirsutum.

The fiber length-related qFL-A12-5 identified in CSSLs introgressed from Gossypium barbadense into Gossypium hirsutum was fine-mapped to an 18.8 kb region on chromosome A12, leading to the identification of the GhTPR gene as a potential regulator of cotton fiber length. Fiber length is a key determinant of fiber quality in cotton, and it is a key target of artificial selection for breeding and domestication. Although many fiber length-related quantitative trait loci have been identified, there are few reports on their fine mapping or candidate gene validation, thus hampering efforts to understand the mechanistic basis of cotton fiber development. Our previous study identified the qFL-A12-5 associated with superior fiber quality on chromosome A12 in the chromosome segment substitution line (CSSL) MBI7747 (BC4F3:5). A single segment substitution line (CSSL-106) screened from BC6F2 was backcrossed to construct a larger segregation population with its recurrent parent CCRI45, thus enabling the fine mapping of 2852 BC7F2 individuals using denser simple sequence repeat markers to narrow the qFL-A12-5 to an 18.8 kb region of the genome, in which six annotated genes were identified in Gossypium hirsutum. Quantitative real-time PCR and comparative analyses led to the identification of GH_A12G2192 (GhTPR) encoding a tetratricopeptide repeat-like superfamily protein as a promising candidate gene for qFL-A12-5. A comparative analysis of the protein-coding regions of GhTPR among Hai1, MBI7747, and CCRI45 revealed two non-synonymous mutations. The overexpression of GhTPR resulted in longer roots in Arabidopsis, suggesting that GhTPR may regulate cotton fiber development. These results provide a foundation for future efforts to improve cotton fiber length.

Potassium ameliorates cotton (Gossypium hirsutum L.) fiber length by regulating osmotic and K+ /Na+ homeostasis under salt stress.

Potassium (K) application can alleviate cotton salt stress, but the regulatory mechanisms affecting cotton fiber elongation and ion homeostasis are still unclear. A two-year field experiment was conducted to explore the effects of K on the osmolyte contents (soluble sugar, K+ content, and malate) and related enzyme activities during the fiber elongation of two cotton cultivars with contrasting salt sensitivity (CCRI-79; salt tolerant cultivar, and Simian 3; salt-sensitive cultivar). Three K application treatments (0, 150, and 300 kg K2 O ha-1 ) were applied at three soil salinity levels (low salinity, EC=1.73 ± 0.05 dS m-1 ; medium salinity, EC=6.32 ± 0.10 dS m-1 ; high salinity, EC=10.84 ± 0.24 dS m-1 ). K application improved fiber length and alleviated salt stress by increasing the maximum velocity of fiber elongation (Vmax ). The increase rate of K on fiber length decreased with elevating salt stress, and the increase rate of K on Vmax of CCRI-79 was greater than that of Simian3. K application can increase the enzyme activities (phosphoenolpyruvate carboxylase, PEPC, E.C. 4.1.1.31; pyrophosphatase, PPase, E.C. 3.6.1.1; and plasma membrane H+ -ATPase, PM H+ -ATPase, E.C. 3.6.3.14) as well as the content of osmolytes associated with the enzymes mentioned above. K increased the osmolyte contents under salt stress, and the increase in the K+ content of the fibers was much higher than that of soluble sugar and malate. The results of this study indicated K fertilizer application rates regulate the metabolism of osmolytes in cotton fiber development under salt stress, K+ is more critical to fiber elongation.

Correction to: A conserved cellular mechanism for cotton fibre diameter and length control

Correction to: A conserved cellular mechanism for cotton fibre diameter and length control

Genetic Basis of Cotton Fiber Length and Strength

Genetic Basis of Cotton Fiber Length and Strength

Tissue specific expression of bacterial cellulose synthase (Bcs) genes improves cotton fiber length and strength

Fiber growing inside the cotton bolls is a highly demandable product and its quality is key to the success of the textile industry. Despite the various efforts to improve cotton fiber staple length Pakistan has to import millions of bales to sustain its industrial needs. To improve cotton fiber quality Bacterial cellulose synthase (Bcs) genes (acsA, acsB) were expressed in a local cotton variety CEMB-00. In silico studies revealed a number of conserved domains both in the cotton-derived and bacterial cellulose synthases which are essential for the cellulose synthesis. Transformation efficiency of 1.27% was achieved by using Agrobacterium shoot apex cut method of transformation. The quantitative mRNA expression analysis of the Bcs genes in transgenic cotton fiber was found to be many folds higher during secondary cell wall synthesis stage (35 DPA) than the expression during elongation phase (10 DPA). Average fiber length of the transgenic cotton plant lines S-00–07, S-00–11, S-00–16 and S-00–23 was calculated to be 13.02% higher than that of the non-transgenic control plants. Likewise, the average fiber strength was found to be 20.92% higher with an enhanced cellulose content of 22.45%. The mutated indigenous cellulose synthase genes of cotton generated through application of CRISPR/Cas9 resulted in 6.03% and 12.10% decrease in fiber length and strength respectively. Furthermore, mature cotton fibers of transgenic cotton plants were found to have increased number of twists with smooth surface as compared to non-transgenic control when analyzed under scanning electron microscope. XRD analysis of cotton fibers revealed less cellulose crystallinity index in transgenic cotton fibers as compared to control fibers due to deposition of more amorphous cellulose in transgenic fibers as a result of Bcs gene expression. This study paved the way towards unraveling the fact that Bcs genes influence cellulose synthase activity and this enzyme helps in determining the fate of cotton fiber length and strength.

Potassium Application Increases Cotton (Gossypium hirsutum L.) Fiber Length by Improving K+/Na+ Homeostasis and Potassium Transport Capacity in the Boll-Leaf System under Moderate Salinity

Cotton has a high salt tolerance. However, due to the high salt content and low K+/Na+ ratio in saline soils, cotton yield and fiber quality are difficult to improve. To investigate the effects of potassium (K) on cotton fiber length under salt stress, a two-year bucket-based field experiment was conducted using two different cultivars (CCRI 79, salt tolerant, and Simian 3, salt sensitive). Three K rates (K0, 0 kg K2O ha−1; K150, 150 kg K2O ha−1; and K300, 300 kg K2O ha−1) were applied at low, middle, and high soil electrical conductivities (S1, 1.7–1.8 dS m−1; S2, 6.4–6.9 dS m−1; and S3, 10.6–11.8 dS m−1) to investigate the absorption, transport, and distribution characteristics of K+ and Na+ in the boll-leaf system (including the leaf subtending the cotton boll (LSCB), fruiting branch, boll shell, and fiber) of both cotton cultivars, as well as the relationship with fiber length. The results showed that K application (K150 and K300) significantly increased the cotton fiber length under salt stress, with the largest fiber length alleviation coefficients (AC) in the middle fruiting branches. The AC decreased with an increase in salt stress and was greater in CCRI 79 than in Simian 3. The K150 treatment (soil K+/Na+ = 1/13) completely mitigated the reduction in fiber length caused by S2 salt stress in CCRI 79, whereas the K300 treatment (soil K+/Na+ = 1/10) completely eased the reduction in fiber length caused by S2 salt stress in Simian 3. An application of K under salt stress increased the K+ content and K+/Na+ ratio in the soil and the organs of the boll-leaf system, regulated the K+/Na+ homeostasis in the boll-leaf system, enhanced the K+-selective transport coefficient (SK-Na) in the LSCB, maintained a high K+/Na+ ratio in the fiber, and mitigated the fiber length reduction. In conclusion, the fiber length reduction in salt-tolerant cultivars was completely mitigated by K150 (i.e., soil K+/Na+ = 1/13) under moderate salt stress; however, it was not completely mitigated by K application under high salt stress.

Reconstruction of the cotton fiber length distribution from a High Volume Instrument® fibrogram

Cotton fiber length is one of the most critical parameters of fiber quality for ring-spun and air-jet-spun yarns. Currently, two of the most common instruments for testing cotton fiber length are the USTER High Volume Instrument (HVI) and the USTER Advanced Fiber Information System (AFIS). The HVI bases its length measurement on the fibrogram concept. It is fast but reports only two length measurements—the upper half mean length (UHML) and the uniformity index (UI), where the UI is the percentage ratio of mean length (ML) to UHML. The AFIS is slower and more costly per test because it individualizes fibers to provide a complete fiber length distribution per sample. This paper presents a method that can reconstruct a complete fiber length distribution from an HVI fibrogram based on established fibrogram theory. Results show that the algorithm can accurately recover different types of distributions based on synthetically generated data. Results also show that reconstructed distributions of three different types of samples—upland, pima, and viscose—differ in ways that make sense based on known characteristics of their length distributions. Finally, a variety of statistics computed from the reconstructed distributions are compared to the HVI-reported length parameters. Results show a good correlation with HVI output with R2 ranging from 0.730 to 0.965 across nine different methods of calculating the ML, UHML, and UI. Interestingly, statistics calculated from an approximation of the length distribution by weight are the most closely related to the HVI length parameters.

Analysis of the MIR396 gene family and the role of MIR396b in regulating fiber length in cotton.

Cotton fiber is one of the most important natural raw materials in the world textile industry. Improving fiber yield and quality has always been the main goal. MicroRNAs, as typical small noncoding RNAs, could affect fiber length during different stages of fiber development. Based on differentially expressed microRNA in the two interspecific backcross inbred lines (BILs) with a significant difference in fiber length, we identified the miR396 gene family in the two tetraploid cotton genomes and found MIR396b_D13 as the functional precursor to produce mature miR396 during the fiber elongation stage. Among 46 target genes regulated by miR396b, the GROWTH-REGULATING FACTOR 5 gene (GRF5, Gh_A10G0492) had a differential expression level in the two BILs during fiber elongation stage. The expression patterns indicated that the miR396b-GRF5 regulatory module has a critical role in fiber development. Furthermore, virus-induced gene silencing (VIGS) of miR396b significantly produced longer fiber than the wild type, and the expression level of GRF5 showed the reverse trends of the miR396b expression level. The analysis of co-expression network for the GRF5 gene suggested that a cytochrome P450 gene functions as an allene oxide synthase (Gh_D06G0089, AOS), which plays a critical role in jasmonate biosynthetic pathway. In conclusion, our results revealed that the miR396b-GRF5 module has a critical role in fiber development. These findings provide a molecular foundation for fiber quality improvement in the future.

GhROP6 GTPase modulates auxin accumulation in cotton fibers by regulating cell-specific GhPIN3a localization.

PIN-FORMED- (PIN) mediated polar auxin transport plays a predominant role in most auxin-triggered organogenesis in plants. Global control of PIN polarity at the plasma membrane contributes to the essential establishment of auxin maxima in most multicellular tissues. However, establishment of auxin maxima in single cells is poorly understood. Cotton fibers, derived from ovule epidermal cells by auxin-triggered cell protrusion, provide an ideal model to explore the underlying mechanism. Here, we report that cell-specific degradation of GhPIN3a, which guides the establishment of the auxin gradient in cotton ovule epidermal cells, is associated with the preferential expression of GhROP6 GTPase in fiber cells. In turn, GhROP6 reduces GhPIN3a abundance at the plasma membrane and facilitates intracellular proteolysis of GhPIN3a. Overexpression and activation of GhROP6 promote cell elongation, resulting in a substantial improvement in cotton fiber length.

Fine-mapping and candidate gene analysis of qFL-c10-1 controlling fiber length in upland cotton (Gossypium hirsutum L.).

A fiber length QTL, qFL-c10-1, was fine-mapped to a 96.5-kb region containing one gene that has not been characterized in plants. Fiber length is an important component of cotton fiber quality, which is associated with other quality properties such as fiber strength, fiber maturity, and fineness. In our previous studies, a stable QTL qFL-c10-1 controlling fiber length had been identified on chromosome A10 in an upland cotton recombinant inbred line (RIL) population from a cross between Jimian5 and DH962. To fine-map qFL-c10-1, an F2 population with 1081 individual plants from a cross between a recombinant line DJ61 and Jimian5 was established. Using linkage analysis and progeny recombination experiment, qFL-c10-1 was mapped into a 96.5-kb genomic region that just contained one proper transcript Ghir_A10G022020 (described as GhFL10), an undescribed gene in plants. One 214-bp deletion was identified in the promoter region of DJ61 compared with Jimian5. Quantitative real-time PCR (qRT-PCR) and comparative analysis of parental sequences suggested that GhFL10 was the most promising candidate gene for qFL-c10-1. According to RNA-seq, yeast two-hybrid assay and bimolecular fluorescence complementation (BiFC), we speculate that GhFL10 interacts with NF-YA transcription factors to negatively regulate fiber elongation.

Down-regulating a fiber-specific KCR like gene GhKCRL1 suppressed fiber elongation through blocking the synthesis of sphingolipids in fiber cell

Cotton is an important natural fiber crop in the world. Cotton fiber cell is an extremely elongated single-cell trichome of seeds. Therefore, the fiber cell is an ideal model for studying plant cell elongation (polar expansion) and secondary wall deposition. Moreover, the two processes determine the quality (length, strength and fineness) of mature cotton fiber. However, the regulatory mechanism of fiber elongation remains unclear. Ligon lintless-1 ( Li-1 ) mutant is a fiber elongation mutant and a good material to study fiber elongation. In the present study, through analyzing the different expression genes in 10-DPA (day post anthesis) fiber cell of Li-1 mutant and its wild type (TM-1), we found a KCR (3-Ketoacyl-Coenzyme A Reductase) like gene, GhKCRL1 , was strikingly down-regulated in Li-1 mutant. GhKCRL1 shared low sequence identity with the 17 beta-hydroxysteroid dehydrogenase 12 of animal and the reported GhKCR1, GhKCR2, and GhKCR3 of upland cotton. GhKCRL1 was specifically expressed in fiber cells and its expression level peaked in 10-DPA fiber cells. GhKCRL1 is located in the endoplasmic reticulum . Down-regulating the expression of GhKCRL1 suppressed fiber elongation and significantly shortened mature fiber length. The sphingolipids contained VLCFA and LCFA strikingly declined in RNAi fiber cells. Consistently, the expression levels of most genes involved in sphingolipid biosynthesis and very long chain fatty acid (VLCFA) biosynthesis decreased in GhKCRL1 down-regulated cotton fibers. And the exogenous application of VLCFA (C24 FA) could rescue the elongation of GhKCRL1 down-regulated fiber cells. Taken together, the results revealed that the fiber-specific GhKCRL1 play some roles in cotton fiber elongation by regulating sphingolipid biosynthesis. Pattern diagram of the GhKCRL regulating fiber elongation. • GhKCRL1 is a novel KCR gene in upland cotton. • GhKCRL1 specifically expressed in fibers cells. • Down-regulating GhKCRL1 expression suppressed fiber cell elongation. • Down-regulating GhKCRL1 blocking the synthesis of sphingolipids in fiber cell.

A novel parent selection strategy for the development of salt-tolerant cotton cultivars

AbstractSalinity poses a major obstacle in increasing the yield of cotton. To explore genetic material that can yield better under salt stress conditions, eight parents including 5 females and 3 testers were crossed in line × tester mating design. After successful completion of crossing, parents and their 15 crosses were evaluated for seed cotton yield, within boll yield components, fibre quality, ionic and biochemical traits under control and NaCl salt stressed conditions (10 and 20 dSm−1). Under salt stress conditions seed cotton yield, fibre length and fibre strength decreased in all genotypes whereas, lint percentage and fibre fineness increased. Among parents RH-647 and among crosses FH-214 × FH-2015 performed better for seed cotton yield while for fibre quality traits under salt stress conditions among parents KEHKSHAN, and among crosses FH-214 × KEHKSHAN performed better. Results suggested that plant height, boll weight, lint percentage, fibre length and fibre strength are reliable traits for the selection of salt tolerant genotypes in the future cotton breeding programs.