BACKGROUND: Calcium-dependent protein kinase (CDPK) plays a key role in cotton tolerance to abiotic stress. However, its role in cotton heat stress tolerance is not well understood. Here, we characterize the GhCDPK gene family and their expression profiles with the aim of identifying CDPK genes associated with heat stress tolerance.
RESULTS: This study revealed 48 GhCDPK members in the cotton genome, distributed on 18 chromosomes. Tree phylogenetic analysis showed three main clustering groups of the GhCDPKs. Cis-elements revealed many abiotic stress and phytohormone pathways conserved promoter regions. Similarly, analysis of the transcription factor binding sites (TFBDS) in the GhCDPK genes showed many stress and hormone related sites. The expression analysis based on qRT-PCR showed that GhCDPK16 was highly responsive to high-temperature stress. Subsequent protein-protein interactions of GhCDPK16 revealed predictable interaction with ROS generating, calcium binding, and ABA signaling proteins. Overexpression of GhCDPK16 in cotton and Arabidopsis improved thermotolerance by lowering ROS compound buildup. Under heat stress, GhCDPK16 transgenic lines upregulated heat-inducible genes GhHSP70, GHSP17.3, and GhGR1, as demonstrated by qRT-PCR analysis. Contrarily, GhCDPK16 knockout lines in cotton exhibited an increase in ROS accumulation. Furthermore, antioxidant enzyme activity was dramatically boosted in the GhCDPK16-ox transgenic lines.
CONCLUSIONS: The collective findings demonstrated that GhCDPK16 could be a viable gene to enhance thermotolerance in cotton and, therefore, a potential candidate gene for improving heat tolerance in cotton.

Off-target pesticide drift from cropland is a major source of pesticide exposure to pollinating insects inhabiting crop and wildlands in the lower Mississippi Delta (LMD) in the USA. This study is aimed to develop a drift-reducing pesticide adjuvant that is less/nontoxic to honeybees. Ongoing toxicology experiments with two widely-used insecticides and sodium alginate (SA) pointed out reductions in honeybee mortality compared to an industry standard reference polyacrylamide (PAM). When used as an adjuvant to spray the same insecticides described above, SA did not interfere in killing the target pests. Therefore, SA has been tested as a drift-reducing pesticide adjuvant to protect honeybees. Spray experiments in the lab were carried out in four sets: (i) water only, (ii) water and adjuvant, (iii) water and pesticide, and (iv) water, pesticide and adjuvant. Each set contained 18 treatment combinations to cover the ranges in spray pressure (three), adjuvant dose (three), and spray nozzles (two). The droplet spectrum was analyzed using a P15 image analyzer. Diameters of 10 %, 50 % and 90 % volumes (DV10, DV50, and DV90), droplet velocity, standard deviation and relative span were measured. The drift reduction potential (DRP) of SA was analyzed by (i) dose, (ii) spray pressure, and (iii) nozzle type. The DRP of SA is compared to that of PAM. Additionally, three field experiments were carried out to analyze the efficiency of SA in reducing pesticide drift. The results from our experiments collectively indicate that SA has significant potential in mitigating drift as well as minimizing pesticide toxicity to honeybees.

Flowering in plants is pivotal for initiating and advancing reproductive processes, impacting regional adaptation and crop yield. Despite numerous cloned and identified flowering time genes, research in cotton remains sparse. This study identified GhSWEET42 as a key determinant of the flowering time in cotton, demonstrating that its heterologous expression in Arabidopsis accelerated flowering under LD conditions compared to WT. Transgenic plants exhibited upregulated expression of the flowering inducers AtFT, AtSOC1, AtGI, and AtFKF1, alongside downregulated expression of the repressors AtTSF, AtFLC, and AtRGL2, correlating with the earlier flowering phenotype. GhSWEET42 showed a constitutive expression pattern, with elevated levels in the leaves, petals, and flower buds, and was notably higher in early-maturing cotton varieties. Subcellular localization assays confirmed GhSWEET42\'s presence on the cell membrane. Transcriptome analysis between WT and GhSWEET42-overexpressing Arabidopsis plants revealed 2393 differentially expressed genes (DEGs), spanning 221 biological processes, 93 molecular functions, and 37 cellular components according to Gene Ontology (GO) enrichment analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis categorized the DEGs into metabolism and environmental information processing. These findings enhance the understanding of GhSWEET42\'s function and provide a foundation for elucidating the molecular mechanisms governing flowering time regulation in cotton.

Somatic embryogenesis (SE) is a biotechnological tool used to generate new individuals and is the preferred method for rapid plant regeneration. However, the molecular basis underlying somatic cell regeneration through SE is not yet fully understood, particularly regarding interactions between the proteome and post-translational modifications. Here, we performed association analysis of high-throughput proteomics and phosphoproteomics in three representative samples (non-embryogenic calli, NEC; primary embryogenic calli, PEC; globular embryos, GE) during the initiation of plant regeneration in cotton, a pioneer crop for genetic biotechnology applications. Our results showed that protein accumulation is positively regulated by phosphorylation during SE, as revealed by correlation analyses. Of the 1418 proteins that were differentially accumulated in the proteome and the 1106 phosphoproteins that were differentially regulated in the phosphoproteome, 115 proteins with 229 phosphorylation sites overlapped (co-differential). Furthermore, seven dynamic trajectory patterns of differentially accumulated proteins (DAPs) and the correlated differentially regulated phosphoproteins (DRPPs) pairs with enrichment features were observed. During the initiation of plant regeneration, functional enrichment analysis revealed that the overlapping proteins (DAPs-DRPPs) were considerably enriched in cellular nitrogen metabolism, spliceosome formation, and reproductive structure development. Moreover, 198 DRPPs (387 phosphorylation sites) were specifically regulated at the phosphorylation level and showed four patterns of stage-enriched phosphorylation susceptibility. Furthermore, enrichment annotation analysis revealed that these phosphoproteins were significantly enriched in endosomal transport and nucleus organization processes. During embryogenic differentiation, we identified five DAPs-DRPPs with significantly enriched characteristic patterns. These proteins may play essential roles in transcriptional regulation and signaling events that initiate plant regeneration through protein accumulation and/or phosphorylation modification. This study enriched the understanding of key proteins and their correlated phosphorylation patterns during plant regeneration, and also provided a reference for improving plant regeneration efficiency.

UNASSIGNED: As leaves grow, they transition from a low-microbe environment embedded in shoot apex to a more complex one exposed to phyllosphere microbiomes. Such change requires a coordinated reprogramming of cellular responses to biotic stresses. It remains unclear how plants shift from fast growth to robust resistance during organ development.
UNASSIGNED: Here, we reported that salicylic acid (SA) accumulation and response were temporarily increased during leaf maturation in herbaceous annual Arabidopsis. Leaf primordia undergoing active cell division were insensitive to the elicitor-induced SA response. This age-dependent increase in SA response was not due to prolonged exposure to environmental microbes. Autoimmune mutants with elevated SA levels did not alter the temporal pattern dependent on ontogenic stage. Young Arabidopsis leaves were more susceptible than mature leaves to Pseudomonas syringae pv. tomato (Pto) DC3000 cor- infection. Finally, we showed a broadly similar pattern in cotton, a woody perennial, where young leaves with reduced SA signaling were preferentially invaded by a Xanthomonas pathogen after leaf surface infection.
UNASSIGNED: Through this work, we provided insights in the SA-mediated ontogenic resistance in Arabidopsis and tomato.

Chitinase genes, as a class of cell wall hydrolases, are essential for the development and pathogenesis of Fusarium oxysporum f.sp. vasinfectum (F. ox) in cotton, but related research focused on chitinase genes are limited. This study explored two island cotton root secretions from the highly resistant cultivar Xinhai 41 and sensitive cultivar Xinhai 14 to investigate their interaction with F. ox by a weighted correlation network analysis (WGCNA). As a result, two modules that related to the fungal pathogenicity emerged. Additionally, a total of twenty-five chitinase genes were identified. Finally, host-induced gene silencing (HIGS) of FoChi20 was conducted, and the cotton plants showed noticeably milder disease with a significantly lower disease index than the control. This study illuminated that chitinase genes play crucial roles in the pathogenicity of cotton wilt fungi, and the FoChi20 gene could participate in the pathogenesis of F. ox and host-pathogen interactions, which establishes a theoretical framework for disease control in Sea Island cotton.

The growing activity in the textile industry has been demanding the search for new and innovative technologies to meet consumers\' needs regarding more sustainable and ecological processes, with functionality receiving more attention. Bee products are known for their wide spectra of properties, including antioxidant and antibacterial activities. Propolis and honey are the most popular and used since ancient times for the most diverse applications due to their health benefits. With the increasing need for safer and more sustainable practices, the use of natural products for the functional finishing process can be a suitable alternative due to their safety and eco-friendly nature. For that, a biosolution, composed of a mixture of propolis and honey in water, was used to perform the functional finishing of cotton knits, both in the presence and in the absence of potassium alum as a chemical mordant. The fastness strength was also evaluated after three washing cycles. The antioxidant potential of the biosolution, assessed with the in vitro ABTS scavenging assay, provided textiles with the capacity to reduce more than 90% of the ABTS radical, regardless of the mordant presence and even after three washing cycles. Furthermore, biofunctional textiles decreased the growth of Bacillus subtilis, Propionibacterium acnes, Escherichia coli, and, particularly, Staphylococcus aureus cultures after 24 h of incubation with an increase in antibacterial activity when potassium alum was used. These findings show that bee products are promising and effective alternatives to be used in the textile industry to confer antioxidant and antibacterial properties to cotton textiles, thereby enhancing human health.

In the textile industry, cotton and polyester (PES) are among the most used fibres to produce clothes. The correct identification and accurate composition estimate of fibres are mandatory, and environmentally friendly and precise techniques are welcome. In this context, the use of near-infrared (NIR) and mid-infrared (MIR) spectroscopies to distinguish between cotton and PES samples and further estimate the cotton content of blended samples were evaluated. Infrared spectra were acquired and modelled through diverse chemometric models: principal component analysis; partial least squares discriminant analysis; and partial least squares (PLS) regression. Both techniques (NIR and MIR) presented good potential for cotton and PES sample discrimination, although the results obtained with NIR spectroscopy were slightly better. Regarding cotton content estimates, the calibration errors of the PLS models were 3.3% and 6.5% for NIR and MIR spectroscopy, respectively. The PLS models were validated with two different sets of samples: prediction set 1, containing blended cotton + PES samples (like those used in the calibration step), and prediction set 2, containing cotton + PES + distinct fibre samples. Prediction set 2 was included to address one of the biggest known drawbacks of such chemometric models, which is the prediction of sample types that are not used in the calibration. Despite the poorer results obtained for prediction set 2, all the errors were lower than 8%, proving the suitability of the techniques for cotton content estimation. It should be stressed that the textile samples used in this work came from different geographic origins (cotton) and were of distinct presentations (raw, yarn, knitted/woven fabric), which strengthens our findings.

Cotton is used for the production of textiles, hygiene and cosmetic materials. During cultivation and technological processes, various types of substances (surfactants, softeners, lubricants, etc.) penetrate cotton, which can have a harmful effect on both the human body and the environment. The aim of this study was to analyze selected cotton products in order to identify the substances contained and to describe the potential possibilities of inducing textile contact dermatitis (CD). The impact of the identified compounds on the aquatic environment was also taken into account. Nine samples of cotton clothing and seven samples of cotton pads from various manufacturers were tested. Samples after extraction using the FUSLE (Focused Ultrasonic Liquid Extraction) technique were analyzed with GC/MS. Qualitative analysis was based on comparing mass spectra with library spectra using the following mass spectra deconvolution programs: MassHunter (Agilent), AMDIS (NIST), and PARADISE (University of Copenhagen). The parameter confirming the identification of the substance was the retention index. Through the non-target screening process, a total of 36 substances were identified, with an average AMDIS match factor of approximately 900 (\"excellent match\"). Analyzing the properties of the identified compounds, it can be concluded that most of them have potential properties that can cause CD, also due to the relatively high content in samples. This applies primarily to long-chain alkanes (C25-C31), saturated fatty acids, fatty alcohols (e.g., oleyl alcohol), and fatty acid amides (e.g., oleamide). However, there are not many reports describing cases of cotton CD. Information on the identified groups of compounds may be helpful in the case of unexplained sources of sensitization when the skin comes into contact with cotton materials. Some of the identified compounds are also classified as dangerous for aquatic organisms, especially if they can be released during laundering.

Cotton is one of the world\'s most important economic crops. Verticillium wilt is a devastating cotton disease caused by Verticillium dahliae, significantly impacting cotton yield and quality. E3 ubiquitin ligases are essential components of the ubiquitin-mediated 26S proteasome system, responsible for recognizing ubiquitinated target proteins and promoting their degradation, which play a crucial regulatory role in plant immune responses. In this study, on the basis of the confirmation of differential expression of GhDIRP1, a RING-type E3 ubiquitin ligase encoding gene, in two cotton varieties resistant (Zhongzhimian 2) or susceptible (Jimian 11) to V. dahliae, we demonstrated that GhDIRP1 is a negative regulator of V. dahliae resistance because silencing GhDIRP1 in cotton and heterogeneously overexpressing the gene in Arabidopsis enhanced and compromised resistance to V. dahliae, respectively. The GhDIRP1-mediated immune response seemed to be realized through multiple physiological pathways, including hormone signaling, reactive oxygen species, and lignin biosynthesis. Based on the sequences of GhDIRP1 isolated from Zhongzhimian 2 and Jimian 11, we found that GhDIRP1 had identical coding but different promoter sequences in the two varieties, with the promoter of Zhongzhimian 2 being more active than that of Jimian 11 because the former drove a stronger expression of GUS and LUC reporter genes. The results link the ubiquitination pathway to multiple physiological pathways acting in the cotton immune response and provide a candidate gene for breeding cotton varieties resistant to V. dahliae.