Cultivated Cotton Research Articles

TRACING THE DIVERSITY OF CULTIVATED TRANSGENIC COTTON IN PAKISTAN BY SSR BASED DNA FINGERPRINTING

The introduction of transgenic Bacillus thuringiensis (Bt) cotton is one of the success stories of applying biotechnology in agriculture. It also decreased the use of insecticides and the production cost as an environmental and economic benefit, respectively. The use of selective genotypes as a parental material for Bt cotton breeding has resulted in the multiplication of limited germplasm. The main objective of the study was to find out the genetic diversity of cultivated Bt cotton genotypes by fingerprinting. Twenty-two SSR markers were used to analyze the genetic differences in Bt cotton genotypes, collected from two different sources i.e., research institutes and open market. Results showed that the Polymorphism information content (PIC) value ranged from zero to 0.673. A UPGMA based dendrogram divided all the genotypes into four main clusters. Eighty-six percent similarity was observed between VH-282 and AS-01 while the lowest similarity of 45% was found between IUB-222 and FH-167.This diversity of newly introduced transgenic genotypes will help to detect the diverse lines to be used in future for broadening the genetic base of Bt cotton in Pakistan. Another observation was that a genotype, FH-114 oBtained from two sources was clustered in two different clades. This showed the presence of name variants for a particular genotype depicting adulteration of seed available in seed market which need to be addressed. Though the adoption of Bt cotton was rapid, but the economic impact of this adoption was not significant in Pakistan as compared to other developing countries. The identified problem might be one of the reasons, limiting the benefits of this technology to be harvested out of it.

N6-methyladenosine RNA modification regulates photoperiod sensitivity in cotton.

The methylation of N6-methyladenosine (m6A) involves writers, erasers, and readers, acting synergistically in posttranscriptional regulation. These processes influence various biological processes, including plant floral transition. However, the specific role of m6A modifications in photoperiod sensitivity in cotton (Gossypium hirsutum) remains obscure. To elucidate this, in this study, we conducted transcriptome-wide m6A sequencing during critical flowering transition stages in the photoperiod-sensitive wild G. hirsutum var. yucatanense (yucatanense) and the photoperiod-insensitive cultivated cotton G. hirsutum acc. TM-1 (TM-1). Our results revealed significant variations in m6A methylation of 2 cotton varieties, with yucatanense exhibiting elevated m6A modification levels compared with TM-1 under long-day conditions. Notably, distinct m6A peaks between TM-1 and yucatanense correlated significantly with photoperiod sensitivity. Moreover, our study highlighted the role of the demethylase G. hirsutum ALKB homolog 5 (GhALKBH5) in modulating m6A modification levels. Silencing GhALKBH5 led to a decreased mRNA level of key photoperiodic flowering genes (GhADO3, GhAGL24, and GhFT1), resulting in delayed bud emergence and flowering. Reverse transcription quantitative PCR analyses confirmed that silencing GhADO3 and GhAGL24 significantly downregulated the expression of the floral integrator GhFT1. Collectively, our findings unveiled a transcriptional regulatory mechanism in which GhALKBH5-mediated m6A demethylation of crucial photoperiodic flowering transcripts modulated photoperiod sensitivity in cotton.

Performance and Sustainability of Organic and Conventional Cotton Farming Systems in Egypt: An Environmental and Energy Assessment

Cotton cultivation is resource-intensive, posing significant environmental challenges, especially with conventional farming methods. Growing interest in sustainable agriculture drives the exploration of organic farming as a potential alternative with lower environmental impacts. Despite its benefits, organic farming often faces criticism for lower crop yields, sparking debates on the trade-offs between productivity and environmental impact. This study hypothesizes that organic cotton farming will have a smaller environmental footprint and higher energy efficiency compared to conventional methods. To test this hypothesis, a cradle-to-farm gate energy analysis and life cycle assessment (LCA) were conducted on both organic and conventional seed cotton production systems in the Beheira governorate of Egypt. The ReCiPe 2016 midpoint and endpoint characterization model was used for an environmental impact assessment. The impacts were evaluated using two functional units: one ton of seed cotton and one hectare of cultivated cotton. The findings revealed that organic cotton outperforms conventional cotton in net energy gain, efficiency, and profitability, with higher productivity and lower energy intensity. Regardless of the functional unit used (mass- or land-based), the assessed organic systems generally show a better environmental performance than the conventional systems in the local context, even when accounting for data uncertainty. This is due to lower input intensity and the use of less energy-intensive organic fertilizers and bio-fertilizers. Fertilization and irrigation are key factors influencing environmental impacts, with fertilization affecting midpoint impacts and irrigation affecting endpoint impacts. Therefore, precision fertilization, efficient irrigation practices, and effective nutrient and soil moisture management are recommended to minimize environmental impacts. Subsequent studies could explore whether similar patterns are observed in different geographic regions and evaluate additional social and economic aspects of cotton sustainability beyond environmental impacts. Future agricultural LCAs should use both mass-based and area-based functional units to capture a broader range of environmental effects and evaluate the co-benefits and trade-offs between organic and conventional practices.

Physiological and structural traits contribute to thermotolerance in wild Australian cotton species.

Five species of cotton (Gossypium) were exposed to 38°C days during early vegetative development. Commercial cotton (Gossypium hirsutum) was contrasted with four wild cotton species (G. australe, G. bickii, G. robinsonii and G. sturtianum) that are endemic to central and northern Australia. Plants were grown at daytime maxima of 30°C or 38°C for 25 d, commencing at the four-leaf stage. Leaf areas and shoot biomass were used to calculate relative rates of growth and specific leaf areas. Leaf gas exchange measurements revealed assimilation and transpiration rates, as well as electron transport rates (ETR) and carboxylation efficiency (CE) in steady-state conditions. Finally, leaf morphological traits (mean leaf area and leaf shape were quantified), along with leaf surface decorations, imaged using scanning electron microscopy. Shoot morphology was differentially affected by heat, with three of the four wild species growing faster at 38°C than at 30°C, whereas early growth in G. hirsutum was severely inhibited by heat. Areas of individual leaves and leaf numbers both contributed to these contrasting growth responses, with fewer, smaller leaves at 38°C in G. hirsutum. CO2 assimilation and transpiration rates of G. hirsutum were also dramatically reduced by heat. Cultivated cotton failed to achieve evaporative cooling, contrasting with the transpiration-driven cooling in the wild species. Heat substantially reduced ETR and CE in G. hirsutum, with much smaller effects in the wild species. We speculate that leaf shape, as assessed by invaginations of leaf margins, and leaf size contributed to heat dispersal differentially among the five species. Similarly, reflectance of light radiation was also highly distinctive for each species. These four wild Australian relatives of cotton have adapted to hot days that are inhibitory to commercial cotton, deploying a range of physiological and structural adaptations to achieve accelerated growth at 38°C.

Advances in genome sequencing and artificially induced mutation provides new avenues for cotton breeding.

Cotton production faces challenges in fluctuating environmental conditions due to limited genetic variation in cultivated cotton species. To enhance the genetic diversity crucial for this primary fiber crop, it is essential to augment current germplasm resources. High-throughput sequencing has significantly impacted cotton functional genomics, enabling the creation of diverse mutant libraries and the identification of mutant functional genes and new germplasm resources. Artificial mutation, established through physical or chemical methods, stands as a highly efficient strategy to enrich cotton germplasm resources, yielding stable and high-quality raw materials. In this paper, we discuss the good foundation laid by high-throughput sequencing of cotton genome for mutant identification and functional genome, and focus on the construction methods of mutant libraries and diverse sequencing strategies based on mutants. In addition, the important functional genes identified by the cotton mutant library have greatly enriched the germplasm resources and promoted the development of functional genomes. Finally, an innovative strategy for constructing a cotton CRISPR mutant library was proposed, and the possibility of high-throughput screening of cotton mutants based on a UAV phenotyping platform was discussed. The aim of this review was to expand cotton germplasm resources, mine functional genes, and develop adaptable materials in a variety of complex environments.

Novel powdery mildew of cotton (Gossypium hirsutum) caused by Phyllactinia gossypina sp. nov. in Brazil.

Cotton (Gossypium hirsutum, Malvaceae) is the most important fiber crop in the world. There are published records of many fungal pathogens attacking Gossypium spp., causing numerous diseases, including powdery mildews. Recently, in 2022, non-cultivated spontaneous G. hirsutum plants bearing powdery mildews symptoms were found at roadsides in two municipalities of the state of Minas Gerais (Brazil): Varginha and Ubá. Such localities are situated ca. 260km apart, suggesting a broader distribution of this fungus-host association in Brazil. Samples were taken to the laboratory, and an Ovulariopsis-like, asexual stage of Phyllactinia, was identified forming amphigenous colonies, that were more evident, white and cottony, abaxially. Morphological and molecular data- of the ITS and LSU regions- have shown that colonies from those two samples were of the same fungus species, belonging to a previously unknown species of Erysiphaceae (Ascomycota). The fungus fits into the Phyllactinia clade and is described herein as the new species Phyllactinia gossypina sp. nov. This new species belongs to the 'basal Phyllactinia group', a lineage that includes species known only from the Americas. This report expands the list of pathogenic fungi on cotton. It is early to anticipate whether this new powdery mildew represents a threat to cultivated cotton, which is a major crop in Brazil. Nevertheless, further studies about its infectivity to commercial cotton varieties are recommended, since all known Erysiphaceae are specialized obligate plant parasites and several species cause major losses to important crops.

Genetic Analysis of an F2 Population Derived from the Cotton Landrace Hopi Identified Novel Loci for Boll Glanding.

Landraces are an important reservoir of genetic variation that can expand the narrow genetic base of cultivated cotton. In this study, quantitative trait loci (QTL) analysis was conducted using an F2 population developed from crosses between the landrace Hopi and inbred TM-1. A high-density genetic map spanning 2253.11 and 1932.21 cM for the A and D sub-genomes, respectively, with an average marker interval of 1.14 cM, was generated using the CottonSNP63K array. The linkage map showed a strong co-linearity with the physical map of cotton. A total of 21 QTLs were identified, controlling plant height (1), bract type (1), boll number (1), stem color (2), boll pitting (2), fuzz fiber development (2), boll shape (3), boll point (4), and boll glanding (5). In silico analysis of the novel QTLs for boll glanding identified a total of 13 candidate genes. Analysis of tissue-specific expression of the candidate genes suggests roles for the transcription factors bHLH1, MYB2, and ZF1 in gland formation. Comparative sequencing of open reading frames identified early stop codons in all three transcription factors in Hopi. Functional validation of these genes offers avenues to reduce glanding and, consequently, lower gossypol levels in cottonseeds without compromising the defense mechanisms of the plant against biotic stresses.

Genome-wide identification and mining elite allele variation of the Monoacylglycerol lipase (MAGL) gene family in upland cotton (Gossypium hirsutum L.)

BackgroundMonoacylglycerol lipase (MAGL) genes belong to the alpha/beta hydrolase superfamily, catalyze the terminal step of triglyceride (TAG) hydrolysis, converting monoacylglycerol (MAG) into free fatty acids and glycerol.ResultsIn this study, 30 MAGL genes in upland cotton have been identified, which have been classified into eight subgroups. The duplication of GhMAGL genes in upland cotton was predominantly influenced by segmental duplication events, as revealed through synteny analysis. Furthermore, all GhMAGL genes were found to contain light-responsive elements. Through comprehensive association and haplotype analyses using resequencing data from 355 cotton accessions, GhMAGL3 and GhMAGL6 were detected as key genes related to lipid hydrolysis processes, suggesting a negative regulatory effect.ConclusionsIn summary, MAGL has never been studied in upland cotton previously. This study provides the genetic mechanism foundation for the discover of new genes involved in lipid metabolism to improve cottonseed oil content, which will provide a strategic avenue for marker-assisted breeding aimed at incorporating desirable traits into cultivated cotton varieties.

Pulmonary function assessment among conventional and organic cotton farmers exposed to pesticides in the Central-West region of Burkina Faso.

Respiratory diseases have been associated with the exposure of populations to some environmental pollutants such as pesticides. To assess effects of pesticides on farmers' respiratory health, this study aimed to evaluate the pulmonary function of cotton farmers exposed to synthetic and natural pesticides in the Central-West region of Burkina Faso. A cross-sectional study was conducted from June to July 2022 among 281 conventional and 189 organic cotton farmers. After collecting information on pesticide use conditions, pulmonary function tests (PFTs) were performed on each farmer according to the American Thoracic Society/European Respiratory Society guidelines, in order to assess chronic respiratory effects among cotton producers. Binary logistic regression was used to assess factors associated with the occurrence of ventilatory changes. Both conventional and organic cotton farmers reported similar chronic respiratory symptoms in different proportions. The main reported were rhinitis (54.45% conventional vs. 34.92% organic), chest pains (41.28% conventional vs. 23.81% organic), cough (33.45% conventional, 24.34% organic), breathlessness (31.67% conventional, 4.23% organic) (p<0.05). 16.18% and 27.50% of conventional male and female cotton farmers, respectively, had a restrictive defect. Among organic cotton farmers, 15.85% and 18.69%, respectively, of males and females had a restrictive defect. Furthermore, a significant increase in the predicted average percentage of FEV1/FVC ratio was observed among organic cotton farmers after salbutamol's use (p = 0.039). The type of cultivated cotton was not associated with ventilatory changes neither in the univariate analysis, nor in the multivariate analysis. Other factors such as farmers' age, BMI and insecticides use frequency per year were also important. Farmers who used insecticides more than 6 times per season had an increased risk of developing an obstructive defect (OR = 1.603; 95%CI: 0.484-5.309) compared to those who used them 6 times or less. Chronic respiratory signs and ventilatory impairments were found among conventional and, to our knowledge, for the first time among organic cotton producers. However, these health effects were more prevalent among conventional cotton farmers than organic ones.

Bacterial blight: Once a menacing disease of cotton in India, now tamed and fading from research spotlight

AbstractBacterial blight, incited by Xanthomonas citri pv. malvacearum (Xcm), is historically one of the most devastating diseases of cotton globally. In India, the initial documentation of the disease dates back to 1918 and it assumed a great magnitude after 1947, primarily triggered by cultivation of tetraploid cotton, as the earlier cultivated indigenous diploid cotton was naturally resistant to the pathogen, and became widespread during the 1970s. Among 20 races of bacterial blight pathogen documented at global level, Race 18 is the most virulent one and prominent in India. The pathogen inflicts damage at all crop stages, beginning with seedlings. The disease caused regular yield losses of 30%–35% in India and had become a formidable adversary to cotton cultivation in the country; however, over the years its appearance diminished. Much larger gains were apparently achieved when disease was managed with a combination of seed treatment, foliar sprays and bio‐agents. Furthermore, extensive breeding programmes led to development of resistant cultivars, which proved instrumental in managing the disease. The disease exhibited a sharp decline from the beginning of the 21st century and is now no longer a chronic problem in India. This comprehensive review attempts to provide insight into the dynamic nature of bacterial blight threatening cotton cultivation in India during the last century and the underpinning multifaceted research efforts that paved the way for countering the disease. An attempt is made to discuss the qualitative and quantitative studies on genetics of bacterial blight for facilitating the breeding programmes.

GhCOL2 Positively Regulates Flowering by Activating the Transcription of GhHD3A in Upland Cotton (Gossypium hirsutum L.).

Plants have evolved sophisticated signaling networks to adjust flowering time, ensuring successful reproduction. Two crucial flowering regulators, FLOWERING LOCUS T (FT) and CONSTANS (CO), play pivotal roles in regulating flowering across various species. Previous studies have indicated that suppressing Gossypium hirsutum CONSTANS-LIKE 2 (GhCOL2), a homolog of Arabidopsis CO, leads to delayed flowering in cultivated cotton. However, the underlying regulatory mechanisms remain unknown. In this study, a yeast one-hybrid and dual-LUC expression assays were used to elucidate the molecular mechanism through which GhCOL2 regulates the transcription of GhHD3A. RT-qPCR was used to examine the expression of GhCOL2 and GhHD3A.Our findings reveal that GhCOL2 directly binds to CCACA cis-elements and atypical CORE (TGTGTATG) cis-elements in the promoter regions of HEADING DATE 3A (HD3A), thereby activating GhHD3A transcription. Notably, GhCOL2 and GhHD3A exhibited high expression levels in the adult stage and low levels in the juvenile stage. Interestingly, the expression of GhCOL2 and GhHD3A varied significant between the two cotton varieties (Tx2094 and Maxxa). In summary, our study enhances the understanding of the molecular mechanism by which cotton GhCOL2-GhHD3A regulates flowering at the molecular level. Furthermore, it contributes to a broader comprehension of the GhCOL2-GhHD3A model in G. hirsutum.

The comparison of species diversity and abundance of insect natural enemies in the domesticated species of cotton using the yellow pan trap method.

India is the world's largest cotton producer and the only country that grows all four cultivated cotton species. There have been very few studies on the diversity and abundance of natural enemies of cotton insect pests in these cultivated cotton species. Therefore, the current study (2016-2018) was conducted to assess the diversity and abundance of natural enemies that cultivated cotton species harbour. Phule Dhanwantari, Suraj, Suvin, RCH-2, and DCH-32 were the five genotypes used in the study, each with a distinct genetic background. Using the adiv 2.0.1 and vegan R packages, we identified significant differences in natural enemies in terms of species diversity, richness, evenness, and abundance. Analysis of Similarity (ANOSIM) and Non-metric Multidimensional Scaling (NMDS) indicated substantial differences in the natural enemy community structure among the examined genotypes. A total of 17,279 natural enemies were collected and identified across genotypes from seven predatory families and five parasitoid families. The percentage share of these natural enemy families across genotypes and years, in descending order, is Coccinellidae (28.23%) < Tachinidae (19.23%) < Braconidae (12.68%) < Chrysopidae (11.65%) < Chalcididae (9.41%) < Aphelinidae (6.33%) < Pentatomidae (3.29%) < Ichneumonidae (2.37%) < Syrphidae (2.33%) < Vespidae (1.81%) < Asilidae (1.79%) < Geocoridae (0.89%). Coccinellidae, Tachinidae, Braconidae, Chrysopidae, Chalcididae, and Aphelinidae are the six major families that account for more than 85% of all recorded natural enemies. These six families have a higher percentage share in Phule Dhanwantary (90%) compared to the other genotypes. The conservation and better utilization of these natural enemies are crucial for the ecological and safe management of insect pests in the cotton ecosystem.

Leveraging transcriptomics-based approaches to enhance genomic prediction: integrating SNPs and gene networks for cotton fibre quality improvement.

Cultivated cotton plants are the world's largest source of natural fibre, where yield and quality are key traits for this renewable and biodegradable commodity. The Gossypium hirsutum cotton genome contains ~80K protein-coding genes, making precision breeding of complex traits a challenge. This study tested approaches to improving the genomic prediction (GP) accuracy of valuable cotton fibre traits to help accelerate precision breeding. With a biology-informed basis, a novel approach was tested for improving GP for key cotton fibre traits with transcriptomics of key time points during fibre development, namely, fibre cells undergoing primary, transition, and secondary wall development. Three test approaches included weighting of SNPs in DE genes overall, in target DE gene lists informed by gene annotation, and in a novel approach of gene co-expression network (GCN) clusters created with partial correlation and information theory (PCIT) as the prior information in GP models. The GCN clusters were nucleated with known genes for fibre biomechanics, i.e., fasciclin-like arabinogalactan proteins, and cluster size effects were evaluated. The most promising improvements in GP accuracy were achieved by using GCN clusters for cotton fibre elongation by 4.6%, and strength by 4.7%, where cluster sizes of two and three neighbours proved most effective. Furthermore, the improvements in GP were due to only a small number of SNPs, in the order of 30 per trait using the GCN cluster approach. Non-trait-specific biological time points, and genes, were found to have neutral effects, or even reduced GP accuracy for certain traits. As the GCN clusters were generated based on known genes for fibre biomechanics, additional candidate genes were identified for fibre elongation and strength. These results demonstrate that GCN clusters make a specific and unique contribution in improving the GP of cotton fibre traits. The findings also indicate that there is room for incorporating biology-based GCNs into GP models of genomic selection pipelines for cotton breeding to help improve precision breeding of target traits. The PCIT-GCN cluster approach may also hold potential application in other crops and trees for enhancing breeding of complex traits.

Development of Gossypium hirsutum-Gossypium raimondii introgression lines and its usages in QTL mapping of agricultural traits

Gossypium raimondii (2n=2x=26, D5), an untapped wild species, is the putative progenitor of the D-subgenome of G. hirsutum (2n=4x=52, AD1), an extensively cultivated species. Here, we developed a G. hirsutum (recipient)-G. raimondii (donor) introgression population to exploit favorable QTLs/genes and mapped potential quantitative trait loci (QTLs) from wild cotton species. The introgression population consists of 256 lines with an introgression rate of 52.33% of the genome G. raimondii. The range of introgression segment length was 0.03-19.12 Mb, with an average of 1.22 Mb. The coverage of total introgression fragments was 386.98 Mb from G. raimondii. Further genome-wide association analysis (Q+K+MLM) and QTL mapping (RSTEP-LRT) identified 59 common QTLs, including 14 stable QTLs and 6 common QTL (co-QTL) clusters, and one hotspot of MIC. The common QTLs for seed index showed all positive additive effects, while the common QTLs for boll weight were all negative additive effects, indicating that the linkage between seed index and boll weight could be broken. QTLs for lint percentage showed positive effect and could be beneficial for improving cotton yield. Most QTLs for fiber quality had negative additive effects, implying these QTLs were domesticated/improved in G. hirsutum. A few fiber quality QTLs showed positive additive effects, which could be used to improve cotton fiber quality. These introgression lines developed would be useful for molecular marker-assisted breeding and facilitate us to map QTLs precisely for mining desirable genes from the wild species G. raimondii to improve cultivated cotton in future via a design-breeding approach.

Organic fertility management in cotton Gossypium hirsutum L. fosters arthropod biodiversity and complements pest suppression

AbstractResearch on economic, ecological and relative benefits from organic and conventional farming systems has gained significant importance. Organic farming increases species diversity, enhances biological control services, and thus complements sustainable pest management. However, published literature is scarce on cotton crops grown organically with respect to the abundance and diversity of biological control agents and their effects on herbivore populations, typically from developing nations. To address the question, the non‐transgenic cotton variety CIM‐573 was cultivated under two fertility management systems, that is, organic and conventional in 2019 and 2021, and subsequently, differences in the abundance and diversity of arthropod communities were carried out. We applied cattle manure in organic fields 1 month before planting; however, synthetic fertilizers were used in conventional fields. We sampled arthropods weekly after 7 weeks of sowing from the middle rows of treatments for both types of fields. We recorded 10 herbivores as well as eight natural enemy species. Herbivores were more abundant in conventional cotton. However, natural enemies were higher in organic cotton fields. Principal component analysis of herbivores assemblages depicted that Shannon diversity and abundance were positively correlated in the conventional cotton while Menhinick richness and Simpson dominance index were higher in organic cotton. Likewise, natural enemies' abundance, Shannon diversity, Menhinick richness and Simpson dominance were typically more concentrated in organic cultivated cotton. Regression analysis confirmed that the abundance and diversity of natural enemies played a significant role in lowering herbivores populations. Seed cotton yield was significantly higher in conventional cotton and the yield difference between organic and conventional cotton was 27.98%. Our study clearly demonstrates that organic cotton provides more functional and complementary niches to natural enemies and plays a crucial role in pest suppression. Implications of our results for future pest management with respect to ecosystem services in organically grown cotton crops are also discussed.

Research methods for heritage cotton fibres: case studies from archaeological and historical finds in a Finnish context

Cotton (Gossypium species) was used as textile fibre already in the early Indus culture, and since then it has been cultivated in Tropical and Subtropical regions around the whole planet. The species G. hirsutum is nowadays the dominant cotton crop with more than 90% of the world market, while G. barbadense, G. herbaceum and G. arboreum combined, the other cultivated species of Gossypium genus total a minor part of world’s cotton production. Even in places where cotton was not cultivated, it could be an important trade item and income source for local textile centres, with the imported raw cotton lint being spun, woven and for some part exported from such sites around the globe. This all occurred far away from Finland, until changes brought by the development of long-distance trade and the Industrial Revolution. Based on archaeological finds, cotton as a textile material reached Finland relatively late, in the early Middle Ages. The article focuses on the problematic nature of identifying these cotton finds: whereas modern cotton fibres are easy to identify, the archaeological finds can at first sight be confused with bast or un-degummed silk fibres. This issue will be approached through reviewing recent Finnish cotton finds in heritage textiles. Additionally, the article examines whether the four cultivated cotton species could be differentiated using both classical and newly developed fibre identification methods, such as optical microscopy methods, a Scanning Electron Microscope (SEM), Fourier-transform infrared spectroscopy (FTIR) or Wide-Angle X-ray Scattering (WAXS).

Incidence pattern of pink bollworm, Pectinophora gossypiella (Saund.)on different event Bt and non-Bt cottons

A field experiment was conducted at the Agricultural Research Station, Dharwad Farm, Dharwad, Karnatakaduring 2018-19 to evaluate the performance of cultivated cotton genotypes including Bt and non-Bt against pink bollworm,Pectinophora gossypiella (Saund.) under rainfed conditions. Based on seasonal mean green boll damage, Everest (13.56%)performed better against pink bollworm over single gene BG-I Bt variety PAU Bt-1 (16.55%), BG-I Bt hybrid MRC 6918(25.88%) (Both expressing Cry1Ac) and Arjun-21 Cry1A) and BG-II hybrid MRC 7918 (15.52%).DCH-32 (Non Btinterspecific hybrid) had maximum infestation of 37.59 per cent followed by H×H hybrid DHH-263 (36.34%), Suvin(21.38%), DDhc-11 (21.59%), Sahana (20.21%) and DLSa-17 (18.65%). The maximum larval recovery was 12.66 per 20green bolls in DCH-32 followed by DHH-263 (12.58) and Suvin (11.12). In general, Non-Bt genotypes had higher incidencethan Bt genotypes. Similarly, among Bt toxin, Cry1Ac and Cry2Ab expressing genotype had lower incidence.

Comparative Transcriptome Analysis Revealed Key Genes Regulating Gossypol Synthesis in Tetraploid Cultivated Cotton.

Tetraploid cultivated cotton (Gossypium spp.) produces cottonseeds rich in protein and oil. Gossypol and related terpenoids, stored in the pigment glands of cottonseeds, are toxic to human beings and monogastric animals. However, a comprehensive understanding of the genetic basis of gossypol and gland formation is still lacking. We performed a comprehensive transcriptome analysis of four glanded versus two glandless tetraploid cultivars distributed in Gossypium hirsutum and Gossypium barbadense. A weighted gene co-expression network analysis (WGCNA) based on 431 common differentially expressed genes (DEGs) uncovered a candidate module that was strongly associated with the reduction in or disappearance of gossypol and pigment glands. Further, the co-expression network helped us to focus on 29 hub genes, which played key roles in the regulation of related genes in the candidate module. The present study contributes to our understanding of the genetic basis of gossypol and gland formation and serves as a rich potential source for breeding cotton cultivars with gossypol-rich plants and gossypol-free cottonseed, which is beneficial for improving food safety, environmental protection, and economic gains of tetraploid cultivated cotton.

Bridging molecular genetics and genomics for cotton fiber quality improvement

AbstractUpland cotton (Gossypium hirsutum L.) is the main source of natural fiber for the textile industry. Cotton fibers are unicellular trichomes that emerge from the epidermal cells of the seed. In cultivated cotton species, seed trichomes differentiate into two distinct types, spinnable lint, and short fuzz. The main priority for cotton growers is fiber yield, whereas the textile industry also demands better fiber quality characteristics, such as length, uniformity, strength, maturity, and optimal fineness. However, it is a major challenge for breeders to improve fiber quality while maintaining yield, because of the observed negative correlation between yield and fiber quality traits. Recent technical advances in sequencing and bioinformatics have facilitated the assembly of reference quality genomes of multiple cotton species, bringing a new era for cotton genomics. Available genomic resources will help genetically dissect the agronomic and fiber quality traits of cotton and identify gene variants that can be used for cotton improvement through breeding or biotechnology. Here, we review recent progress in the sequencing of genomes of cotton species and approaches in molecular genetics and genomics for the improvement of cotton fiber quality traits. We discuss progress in the understanding of each stage of cotton fiber development and the remaining challenges.

Genome-wide identification and functional analysis of ICE genes reveal that Gossypium thurberi “GthICE2” is responsible for cold and drought stress tolerance

Cold stress has been found to have a negative impact on cotton growth and annual production. To address this issue, the utilization of cold-tolerant gene resources from wild species of Gossypium is crucial for genetic improvements in cultivated cotton. ICE (inducer of CBF expression) are the key regulators of cold tolerance in plants, however, there is relatively little information on ICE genes in cotton. Herein, we performed comprehensive bioinformatics analyses of the ICE gene family in eight cotton species. Phylogenetic analysis showed that 52 ICE genes were clustered into four subgroups. Cis-regulatory elements analysis suggests that the expression of ICE genes might be regulated by light, plant hormones, and various environment stresses. Higher expression of GthICE2 was observed in leaves as compared to roots and stems, in response to cold, drought, and exogenous hormone ABA. Furthermore, overexpression of GthICE2 in A. thaliana led to higher germination and survival rates, longer root length, lower ion leakage, and induction under cold and drought stress. Histochemical staining showed that oxidative damage in transgenic lines was much lower compared to wild-type plants. Lower MDA contents and higher SOD and POD activities were observed in overexpressed plants. Y1H and LUC assays revealed that GthICE2 might activate the expression of GthCBF4, a cold-responsive gene, by connecting with the MYC cis-element present in the promoter of GthCBF4. GthICE2 confers cold and drought stress tolerance in cotton. Our findings add significantly to the existing knowledge regarding cold stress tolerance and helps to elucidate cold response mechanisms in cotton.