Exploring the plasmodesmata callose-binding protein gene family in upland cotton: unraveling insights for enhancing fiber length.

Plasmodesmata are transmembrane channels embedded within the cell wall that can facilitate the intercellular communication in plants. Plasmodesmata callose-binding (PDCB) protein that associates with the plasmodesmata contributes to cell wall extension. Given that the elongation of cotton fiber cells correlates with the dynamics of the cell wall, this protein can be related to the cotton fiber elongation. This study sought to identify PDCB family members within the Gossypium. hirsutum genome and to elucidate their expression profiles. A total of 45 distinct family members were observed through the identification and screening processes. The analysis of their physicochemical properties revealed the similarity in the amino acid composition and molecular weight across most members. The phylogenetic analysis facilitated the construction of an evolutionary tree, categorizing these members into five groups mainly distributed on 20 chromosomes. The fine mapping results facilitated a tissue-specific examination of group V, revealing that the expression level of GhPDCB9 peaked five days after flowering. The VIGS experiments resulted in a marked decrease in the gene expression level and a significant reduction in the mature fiber length, averaging a shortening of 1.43-4.77 mm. The results indicated that GhPDCB9 played a pivotal role in the cotton fiber development and served as a candidate for enhancing cotton yield.

Effect of temperature on the biological parameters of pink bollworm, Pectinophora gossypiella Saunders (Lepidoptera: Gelechiidae).

Pink bollworm (PBW) Pectinophora gossypiella is an important pest cotton worldwide. There are multiple factors which determines the occurrence and distribution of P. gossypiella across different cotton growing regions of the world, and one such key factor is 'temperature'. The aim was to analyze the life history traits of PBW across varying temperature conditions. We systematically explored the biological and demographic parameters of P. gossypiella at five distinct temperatures; 20, 25, 30, 35 and 40 ± 1 °C maintaining a photoperiod of LD 16:8 h. The results revealed that the total developmental period of PBW shortens with rising temperatures, and the highest larval survival rates were observed between 30 °C and 35 °C, reaching 86.66% and 80.67%, respectively. Moreover, significant impacts were observed as the pupal weight, percent mating success, and fecundity exhibited higher values at 30 °C and 35 °C. Conversely, percent egg hatching, larval survival, and adult emergence were notably lower at 20 °C and 40 °C, respectively. Adult longevity decreased with rising temperatures, with females outliving males across all treatments. Notably, thermal stress had a persistent effect on the F1 generation, significantly affecting immature stages (egg and larvae), while its impact on reproductive potential was minimal. These findings offer valuable insights for predicting the population dynamics of P. gossypiella at the field level and developing climate-resilient management strategies in cotton.

The functions of laccase gene GhLAC15 in fiber colouration and development in brown-colored cotton.

The monotonicity of color type in naturally colored cottons (NCCs) has become the main limiting factor to their widespread use, simultaneously coexisting with poor fiber quality. The synchronous improvement of fiber quality and color become more urgent and crucial as the demand for sustainable development increases. The homologous gene of wild cotton Gossypium stocksii LAC15 in G. hirsutum, GhLAC15, was also dominantly expressed in the developing fibers of brown cotton XC20 from 5 DPA (day post anthesis) to 25 DPA, especially at the secondary cell wall thickening stage (20 DPA and 25 DPA). In XC20 plants with downregulated GhLAC15 (GhLAC15i), a remarkable reduction in proanthocyanidins (PAs) and lignin contents was observed. Some of the key genes in the phenylpropane and flavonoid biosynthesis pathway were down-regulated in GhLAC15i plants. Notably, the fiber length of GhLAC15i plants showed an obvious increase and the fiber color was lightened. Moreover, we found that the thickness of cotton fiber cell wall was decreased in GhLAC15i plants and the fiber surface became smoother compared to that of WT. Taken together, this study revealed that GhLAC15 played an important role in PAs and lignin biosynthesis in naturally colored cotton fibers. It might mediate fiber color and fiber quality by catalyzing PAs oxidation and lignin polymerization, ultimately regulating fiber colouration and development.

Investigating the second whitefly population outbreak within a decade in the cotton growing zone of North India.

The whitefly, Bemisia tabaci (Gennadius), is a polyphagous and major pest of cotton worldwide. Both adults and nymphs of B. tabaci affect the crop by causing direct and indirect damage. A severe whitefly outbreak was experienced during 2015 on cotton in North India and this was followed by a profound infestation during 2022. The present research rigorously examined whether the proliferation in the whitefly population was an outbreak or the result of a multi factor resurgence. During 2015, whitefly counts remained above the economic threshold level (ETL) between 28th and 35th Standard Meteorological Week (SMW). However, during 2022 above ETL population was observed in 27th SMW and it persisted until 36th SMW. The peak incidence of the whitefly was noticed during 31st and 29th SMW in 2015 and 2022, respectively. The early pest build up in 2022 and longer persistence (≥10 weeks) over the cotton season resulted in more damage to cotton crop. Additionally, pest survillence across the zone on the farmers' fields during 2022 revealed 44.4 per cent spots (585 out of 1,317 locations) above ETL while the corresponding locations in 2015 was 57% (620 out of 1,089). Thus, in 2022 infestation was not uniform in the entire zone wherein only few blocks of Punjab, Haryana and Rajasthan states of India experienced severe infestations of the whitefly. This study reports the complex of factors including weather, delayed sowing, use of tank mixtures/ subleathal doses of insecticides, pest resurgence etc. that might have possibly contributed to these upsurges in whitefly on cotton in north India.

Expression profile analysis of cotton fiber secondary cell wall thickening stage.

To determine the genes associated with the fiber strength trait in cotton, three different cotton cultivars were selected: Sea Island cotton (Xinhai 32, with hyper-long fibers labeled as HL), and upland cotton (17-24, with long fibers labeled as L, and 62-33, with short fibers labeled as S). These cultivars were chosen to assess fiber samples with varying qualities. RNA-seq technology was used to analyze the expression profiles of cotton fibers at the secondary cell wall (SCW) thickening stage (20, 25, and 30 days post-anthesis (DPA)). The results showed that a large number of differentially expressed genes (DEGs) were obtained from the three assessed cotton cultivars at different stages of SCW development. For instance, at 20 DPA, Sea Island cotton (HL) had 6,215 and 5,364 DEGs compared to upland cotton 17-24 (L) and 62-33 (S), respectively. Meanwhile, there were 1,236 DEGs between two upland cotton cultivars, 17-24 (L) and 62-33 (S). Gene Ontology (GO) term enrichment identified 42 functions, including 20 biological processes, 11 cellular components, and 11 molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis identified several pathways involved in SCW synthesis and thickening, such as glycolysis/gluconeogenesis, galactose metabolism, propanoate metabolism, biosynthesis of unsaturated fatty acids pathway, valine, leucine and isoleucine degradation, fatty acid elongation pathways, and plant hormone signal transduction. Through the identification of shared DEGs, 46 DEGs were found to exhibit considerable expressional differences at different fiber stages from the three cotton cultivars. These shared DEGs have functions including REDOX enzymes, binding proteins, hydrolases (such as GDSL thioesterase), transferases, metalloproteins (cytochromatin-like genes), kinases, carbohydrates, and transcription factors (MYB and WRKY). Therefore, RT-qPCR was performed to verify the expression levels of nine of the 46 identified DEGs, an approach which demonstrated the reliability of RNA-seq data. Our results provided valuable molecular resources for clarifying the cell biology of SCW biosynthesis during fiber development in cotton.

Evolution and subfunctionalization of CIPK6 homologous genes in regulating cotton drought resistance.

The occurrence of whole-genome duplication or polyploidy may promote plant adaptability to harsh environments. Here, we clarify the evolutionary relationship of eight GhCIPK6 homologous genes in upland cotton (Gossypium hirsutum). Gene expression and interaction analyses indicate that GhCIPK6 homologous genes show significant functional changes after polyploidy. Among these, GhCIPK6D1 and GhCIPK6D3 are significantly up-regulated by drought stress. Functional studies reveal that high GhCIPK6D1 expression promotes cotton drought sensitivity, while GhCIPK6D3 expression promotes drought tolerance, indicating clear functional differentiation. Genetic and biochemical analyses confirm the synergistic negative and positive regulation of cotton drought resistance through GhCBL1A1-GhCIPK6D1 and GhCBL2A1-GhCIPK6D3, respectively, to regulate stomatal movement by controlling the directional flow of K+ in guard cells. These results reveal differentiated roles of GhCIPK6 homologous genes in response to drought stress in upland cotton following polyploidy. The work provides a different perspective for exploring the functionalization and subfunctionalization of duplicated genes in response to polyploidization.

Synthesis, characterization, and phosphorus adsorption of Mg/Fe-modified biochar from cotton stalk pretreated with Coriolus versicolor.

In recent years, the research potential in utilizing biochars as adsorbents in adsorption processes has grown due to their eco-friendly and economical nature. However, biochar often possesses a negative surface charge that limits its affinity for binding anions. Nitric acid washing and pretreatment with Coriolus versicolor can break down the lignocellulosic structure in cotton stalk waste, facilitating the subsequent impregnation of Mg and Fe metal oxides. These pretreatment steps can lead to the production of diverse and functionalized biochars with higher adsorption capacities. In this study, cotton stalk waste was first washed with diluted nitric acid and then subjected to biological pretreatment by incubation with C. versicolor, followed by impregnation with Mg and Fe to obtain CV-CS/Fe and CV-CS/Mg biochars. The results showed that the applied pretreatments altered the physicochemical properties and significantly increased the phosphorus adsorption capacity. The adsorption capacities of CV-CS/Fe and CV-CS/Mg biochars were found to be 277.88 and 507.01 mg g-1, respectively. The results indicate that the incorporation of multiple metal oxide impregnates enhances P adsorption. Furthermore, in the kinetic study, pseudo-first-order and pseudo-second-order models provided a well fit, determining chemical adsorption as the main adsorption mechanism for phosphorus adsorption. The biochars demonstrated compatibility with Langmuir-Freundlich models. Overall, the findings suggest the possibility of synthesizing biochars with improved adsorptive properties through pretreatment, and these engineered biochars hold promising potential as effective adsorbents in the field. PRACTITIONER POINTS: Eco-friendly, natural, and economical biochar was synthesized. Biochar was produced via Coriolus versicolor pretreatment. High adsorption capacities of CV-PS/Mg biochars were found to be 507.01 mg g-1. Adsorption capacities of biochars can be improved by pretreatment.

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.

A phenomenological inquiry into farmers' experiences growing cotton in Punjab, Pakistan.

Sustainability in cotton production is inevitable because producing more cotton means more employment, economic acceleration, and industrial expansion. India, China, the United States, Brazil, and Pakistan contribute 74% of worldwide cotton production. Pakistan is contributing only 5%, despite the high potential of cotton. The average yield of cotton in Pakistan is stagnant at 570.99 kg hm-2, whereas it entails the highest cost of production among all other crops. The yield obtained in Pakistan is less than the potential, profitability is drastically lessening, and farmers are abandoning cotton for alternative kharif crops. Some traditional quantitative studies have unveiled different factors that affect cotton production. However, an in-depth qualitative study has never been conducted in Pakistan to explore the root causes of growing cotton crop failure. Following Moustakas's traditional phenomenological guidelines, this phenomenological study was conducted in the district of Rahim Yar Khan in the core cotton zone of Punjab province. A total of 10 interviews were conducted with purposively selected cotton growers based on a criterion: (i) having more than 10 years of cotton growing experience, (ii) being a cotton grower, and (iii) having at least 10 years of formal schooling. Interviews were conducted face to face on an interview guide. One interview lasted 45-50 min, and responses were recorded and analyzed using a thematic analysis approach. A total of 6 themes emerged from the collected data, including (i) climate change, (ii) varietal problems, (iii) pesticide usage, (iv) sense of institutional services, (v) attitude of farmers and (vi) soil health and environment. These six merging themes contributed to cotton crop failure and yield decline. The deep exploration further summarized that researchers, extensionists, and farmers need to seriously consider variety, sowing time, and the environment to revive cotton crops. The detailed recommendations and policy guidelines are presented in this paper, highlighting the cotton sector's research, development and investment areas.

[Effects of Biochar and Straw Return on Soil Microbial Community Characteristics and Functional Differences in Saline Water Drip Irrigation Cotton Fields].

In arid areas, fresh water resources are insufficient, and agricultural water mainly depends on shallow saline groundwater. However, long-term saline irrigation will cause soil salt accumulation and soil environment deterioration, which is not conducive to crop growth. In this study, based on the long-term irrigation of fresh water (0.35 dS·m-1, FW) and saline water (8.04 dS·m-1, SW), biochar (3.7 t·hm-2, BC) and straw (6 t·hm-2, ST) were added to the soil by an equal-carbon design. The aim was to clarify the effects of biochar and straw returning on the physical and chemical properties and microbial community structure of salinized soil. The results showed that saline irrigation significantly increased soil water content, electrical conductivity, available phosphorus, and total carbon content but significantly decreased pH value and available potassium content. The contents of available phosphorus, available potassium, and total carbon in soil were significantly increased by biochar and straw returning, but the conductivity value of soil irrigated with saline water was significantly decreased. The dominant bacteria in each treatment were Proteobacteria, Actinomycetes, Acidobacteria, Chloromycetes, and Blastomonas. Saline water irrigation significantly increased the relative abundance of Blastomonas and Proteobacteria but significantly decreased the relative abundance of Acidobacteria and Actinobacteria. Under the condition of fresh water irrigation, the relative abundance of Chlorocurvula was significantly reduced by the return of biochar. Straw returning significantly increased the relative abundance of Proteobacteria but significantly decreased the relative abundance of Acidobacteria, Actinomyces, Chloromyces, and Blastomonas. Under saline irrigation, the relative abundance of Chlorocurvula and Blastomonas were significantly reduced by biochar return to field. Straw returning significantly increased the relative abundance of Proteobacteria but significantly decreased the relative abundance of Acidobacteria, Actinomyces, Chloromyces, and Blastomonas. LEfSe analysis showed that saline irrigation decreased the potential markers and functional numbers of soil microorganisms.Under saline irrigation, biochar returning increased the number of potential markers and functions of soil microorganisms. Straw returning to field increases the number of potential markers of soil microorganisms. RDA results showed that soil microbial community and functional structure were significantly correlated with EC1:5, SWC, and pH. Saline water irrigation will deteriorate the soil environment, which is not conducive to agricultural production, among which EC1:5, SWC, and pH are important factors driving changes in soil microbial community and functional structure. Using biochar and straw to return to the field can reduce the harm of salt to soil and crops, laying a foundation for improving agricultural productivity.

Diversity study of Beauveria bassiana species for finding the most virulent strain to manage Bemisia tabaci in cotton.

Beauveria bassiana (Bal.-Criv.) is an important entomopathogenic fungus being used for the management of various agricultural pests worldwide. However, all strains of B. bassiana may not be effective against whitefly, Bemisia tabaci, or other pests, and strains show diversity in their growth, sporulation, virulence features, and overall bioefficacy. Thus, to select the most effective strain, a comprehensive way needs to be devised. We studied the diversity among the 102 strains of B. bassiana isolated from 19 insect species based on their physiological features, virulence, and molecular phylogeny, to identify promising ones for the management of B. tabaci. Strains showed diversity in mycelial growth, conidial production, and their virulence against B. tabaci nymphs. The highest nymphal mortality (2nd and 3rd instar) was recorded with MTCC-4511 (95.1%), MTCC-6289 (93.8%), and MTCC-4565 (89.9%) at a concentration of 1 × 106 conidia ml-1 under polyhouse conditions. The highest bioefficacy index (BI) was in MTCC-4511 (78.3%), MTCC-4565 (68.2%), and MTCC-4543 (62.1%). MTCC-4511, MTCC-4565, and MTCC-4543 clustered with positive loading of eigenvalues for the first two principal components and the cluster analysis also corresponded well with PCA (principal component analysis) (nymphal mortality and BI). The molecular phylogeny could not draw any distinct relationship between physiological features, the virulence of B. bassiana strains with the host and location. The BI, PCA, and square Euclidean distance cluster were found the most useful tools for selecting potential entomopathogenic strains. The selected strains could be utilized for the management of the B. tabaci nymphal population in the field through the development of effective formulations. KEY POINTS: • 102 B. bassiana strains showed diversity in growth and virulence against B. tabaci. • Bioefficacy index, PCA, and SED group are efficient tools for selecting potential strains. • MTCC-4511, 4565, and 4543 chosen as the most virulent strains to kill whitefly nymphs.

A cotton mitochondrial alternative electron transporter, GhD2HGDH, induces early flowering by modulating GA and photoperiodic pathways.

D-2-hydroxyglutarate dehydrogenase (D2HGDH) is a mitochondrial enzyme containing flavin adenine dinucleotide FAD, existing as a dimer, and it facilitates the specific oxidation of D-2HG to 2-oxoglutarate (2-OG), which is a key intermediate in the tricarboxylic acid (TCA) cycle. A Genome-wide expression analysis (GWEA) has indicated an association between GhD2HGDH and flowering time. To further explore the role of GhD2HGDH, we performed a comprehensive investigation encompassing phenotyping, physiology, metabolomics, and transcriptomics in Arabidopsis thaliana plants overexpressing GhD2HGDH. Transcriptomic and qRT-PCR data exhibited heightened expression of GhD2HGDH in upland cotton flowers. Additionally, early-maturing cotton exhibited higher expression of GhD2HGDH across all tissues than delayed-maturing cotton. Subcellular localization confirmed its presence in the mitochondria. Overexpression of GhD2HGDH in Arabidopsis resulted in early flowering. Using virus-induced gene silencing (VIGS), we investigated the impact of GhD2HGDH on flowering in both early- and delayed-maturing cotton plants. Manipulation of GhD2HGDH expression levels led to changes in photosynthetic pigment and gas exchange attributes. GhD2HGDH responded to gibberellin (GA3) hormone treatment, influencing the expression of GA biosynthesis genes and repressing DELLA genes. Protein interaction studies, including yeast two-hybrid, luciferase complementation (LUC), and GST pull-down assays, confirmed the interaction between GhD2HGDH and GhSOX (Sulfite oxidase). The metabolomics analysis demonstrated GhD2HGDH's modulation of the TCA cycle through alterations in various metabolite levels. Transcriptome data revealed that GhD2HGDH overexpression triggers early flowering by modulating the GA3 and photoperiodic pathways of the flowering core factor genes. Taken together, GhD2HGDH positively regulates the network of genes associated with early flowering pathways.

Improving the productivity of Xinjiang cotton in heat-limited regions under two life history strategies.

Cotton is a major cash crop globally, playing a pivotal role in the textile sector. However, cotton growers in Xinjiang region are experiencing cotton yield penalty caused by limited heat environment. In this region, limited heat conditions strongly arrest cotton plant growth and development resulting in recued productivity. To counteract this problem, there is an urgent need to robustly identify efficient management strategies to improve plant performance and increase cotton yield under heat-limited situations. This will hold crucial implications for agricultural sustainability and global cotton supply. This review article identified challenges faced by cotton producers under heat limited environments with potential solutions to enhance cotton productivity. Specifically, we focused on the implementation of two life history strategies including planting early maturing and cold tolerant cultivars, and adjusting sowing date that can promote early maturity and increase cold stress tolerance. These strategies have shown promising results in protecting cotton plants from limited heat injury and consequently improved cotton productivity. By focusing on Xinjiang province unique climate and associated agronomic practices, valuable insights can be gained, which may have broader applications in other heat-limited cotton-growing regions globally. This comprehensive review endeavors to provide a foundation for future research and practical interventions aimed at boosting cotton yields under limited heat areas.

Unraveling the complexities of drought stress in cotton: a multifaceted analysis of selection criteria and breeding approaches.

Abiotic stress tolerance breeding programs present a spectrum of perspectives, yet definitive solutions remain elusive, with each approach carrying its own set of advantages and disadvantages. This study systematically evaluates extant methodologies, comparing plant performance across varied genotypes and selection traits under optimal and stress conditions. The objective is to elucidate prevailing ambiguities. Ten homozygous lines (F8 generation) were assessed using a randomized block design alongside five control varieties, with four replicates cultivated under well-watered and deficit water conditions. It is noteworthy that six of the ten homozygous lines were cultivated exclusively under well-watered conditions (F3 to F7), while four lines experienced deficit water conditions (F3 to F7). All five control varieties underwent cultivation under both conditions. These findings underscore the necessity for tailored breeding programs attuned to specific environmental exigencies, recognizing that individual traits manifest divergent responses to varying conditions. It is evident that certain traits exhibit marked disparities under well-watered conditions, while others evince heightened differentiation under water deficit conditions. Significantly, our analysis reveals a pronounced interaction between irrigation regimes and selection traits, which serves to underscore the nuanced interplay between genotype and environmental stress.

Ecotoxicity of Cadmium along the Soil-Cotton Plant-Cotton Bollworm System: Biotransfer, Trophic Accumulation, Plant Growth, Induction of Insect Detoxification Enzymes, and Immunocompetence.

Cadmium (Cd) is a hazardous element that may jeopardize environmental safety and human health through biotransfer and trophic accumulation. Here, we tested Cd toxicity on cotton plants, cotton bollworms, and their responses. Results demonstrated that Cd accumulated in plant roots, aerial parts, insect larvae, pupae, and frass in a dose-dependent pattern. The ∼9.35 mg kg-1 of Cd in plant aerial parts, ∼3.68 in larvae, ∼6.43 in pupae, and high transfer coefficient (∼5.59) indicate significant mobility. The ∼19.61 mg kg-1 of Cd in larvae frass suggests an effective detoxification strategy, while BAFcotton (∼1.14) and BAFworm (∼0.54) indicated low bioaccumulation. Cadmium exposure resulted in compromised plant growth and yield as well as alterations in photosynthetic pigment contents, antioxidant enzyme activities, and certain life history traits of cotton bollworms. Furthermore, carboxylesterase activity and encapsulation rates of insect larvae decreased with increasing Cd concentrations, whereas acetylcholinesterase, phenol oxidase, glutathione S-transferase, and multifunctional oxidase exhibited hormesis responses.

Origin and diversity of the wild cottons (Gossypium hirsutum) of Mound Key, Florida.

Elucidating genetic diversity within wild forms of modern crops is essential for understanding domestication and the possibilities of wild germplasm utilization. Gossypium hirsutum is a predominant source of natural plant fibers and the most widely cultivated cotton species. Wild forms of G. hirsutum are challenging to distinguish from feral derivatives, and truly wild populations are uncommon. Here we characterize a population from Mound Key Archaeological State Park, Florida using genome-wide SNPs extracted from 25 individuals over three sites. Our results reveal that this population is genetically dissimilar from other known wild, landrace, and domesticated cottons, and likely represents a pocket of previously unrecognized wild genetic diversity. The unexpected level of divergence between the Mound Key population and other wild cotton populations suggests that the species may harbor other remnant and genetically distinct populations that are geographically scattered in suitable habitats throughout the Caribbean. Our work thus has broader conservation genetic implications and suggests that further exploration of natural diversity in this species is warranted.

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

BACKGROUND: Monoacylglycerol 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. RESULTS: In 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. CONCLUSIONS: In 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.

Morphological and proteomic study of waterlogging tolerance in cotton.

Floating seedling cultivation technique is a novel seedling method in cotton and it provides an ideal model to study cotton growing under waterlogging stress. Morphological character and proteomic profile of the primary root from the seedling cultured by the new technology were evaluated in this study. Compared to seedlings cultured by the traditional method, the diameter of the taproot from floating technology is small at all five seedling stages from one-leaf stage to five-leaf stage. There are similar changes between the thickness of cortex and diameter of stele, which increased from the one- to the two-leaf stage but decreased from the two- to the five-leaf stage. At the one-leaf stage, the number and volume of mitochondria in the primary root-tip cells were less than those in the control. At the two-leaf stage, there was significantly less electron-dense material in the primary root-tip cells than those in the control group. From the one- to the two-leaf stage, the vacuole volume was significantly smaller than that in the control. Total 28 differentially expressed proteins were revealed from aquatic and control group roots of cotton seedlings at the three-leaf stage by two-dimensional electrophoresis, which included 24 up-regulated and four down-regulated proteins. The relative expression of the phosphoglycerate kinase (PGK) gene in aquatic roots increased from the one- to the four-leaf stage but declined rapidly from the four- to the five-leaf stage. The relative expression of the 14-3-3b gene tended to decrease from the one- to the five-leaf stage. The PGK and 14-3-3b genes were specifically expressed in the aquatic roots at the three-leaf stage. In brief, these changes induced waterlogging resistance in the aquatic roots of cotton seedlings in the floating nursery, thereby causing the roots to adapt to the aquatic environment, promoting the growth and development of cotton seedlings.

Chromosome-level genome assembly and annotation of a potential model organism Gossypium arboreum ZB-1.

Recent advancements in plant regeneration and synthetic polyploid creation have been documented in Gossypium arboreum ZB-1. These developments make ZB-1 a potential model within the Gossypium genus for investigating gene function and polyploidy. This work generated the sequence and annotation of the ZB-1 genome. The contig-level genome was constructed using the PacBio high-fidelity reads, encompassing 81 contigs with an N50 length of 112.12 Mb. The Hi-C data assisted the construction of the chromosome-level genome, which consists of 13 pseudo-chromosomes and 39 un-anchored contigs, with a total length of about 1.67 Gb. Repetitive sequences accounted for about 69.7% of the genome in length. Based on ab initio and evidence-based prediction, we have identified 48,021 protein-coding genes in the ZB-1 genome. Comparative genomics analysis revealed conserved gene content and arrangement between ZB-1 and G. arboreum SXY1. The single nucleotide polymorphism occurrence rate between ZB-1 and SXY1 was about 0.54 per 1,000 nucleotides. This study enriched the genomic resources for further exploration into cotton regeneration and polyploidy mechanisms.

Dominance of Cotton leaf curl Multan virus-Rajasthan strain associated with third epidemic of cotton leaf curl disease in Pakistan.

Cotton (Gossypium hirsutum) is an economically potent crop in many countries including Pakistan, India, and China. For the last three decades, cotton production is under the constant stress of cotton leaf curl disease (CLCuD) caused by begomoviruses/satellites complex that is transmitted through the insect pest, whitefly (Bemisia tabaci). In 2018, we identified a highly recombinant strain; Cotton leaf curl Multan virus-Rajasthan (CLCuMuV-Raj), associated with the Cotton leaf curl Multan betasatellite-Vehari (CLCuMuBVeh). This strain is dominant in cotton-growing hub areas of central Punjab, Pakistan, causing the third epidemic of CLCuD. In the present study, we have explored the CLCuD diversity from central to southern districts of Punjab (Faisalabad, Lodhran, Bahawalpur, Rahimyar Khan) and the major cotton-growing region of Sindh (Tandojam), Pakistan for 2 years (2020-2021). Interestingly, we found same virus (CLCuMuV-Raj) and associated betasatellite (CLCuMuBVeh) strain that was previously reported with the third epidemic in the central Punjab region. Furthermore, we found minor mutations in two genes of CLCuMuV-Raj C4 and C1 in 2020 and 2021 respectively as compared to its isolates in 2018, which exhibited virus evolution. Surprisingly, we did not find these mutations in CLCuMuV-Raj isolates identified from Sindh province. The findings of the current study represent the stability of CLCuMuV-Raj and its spread toward the Sindh province where previously Cotton leaf curl Kokhran virus (CLCuKoV) and Cotton leaf curl Shahdadpur virus (CLCuShV) have been reported. The findings of the current study demand future research on CLCuD complex to explore the possible reasons for prevalence in the field and how the virus-host-vector compatible interaction can be broken to develop resistant cultivars.