Antioxidant defense in cotton under environmental stresses: Unraveling the crucial role of a universal defense regulator for enhanced cotton sustainability.

Cotton (Gossypium spp.) is a globally significant crop that provides natural fibers for the textile industry and also an important oil and biopharmaceutical resources. However, the production of cotton faces substantial challenges due to various biotic and abiotic stress factors that can negatively impact cotton growth, yield, and fiber quality. This review offers a comprehensive overview of the effects of biotic stress factors, such as insect pests, bacterial, fungal, and viral pathogens, and nematodes, as well as abiotic stress factors, including extreme hot and cold temperature, drought, toxicity induced by heavy metal and salinity, on the antioxidant systems in cotton. We discuss the crucial antioxidants, such as glutathione, proline, and phenolics, and highlight major antioxidant enzymes, including ascorbate peroxidase (APX), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione reductase (GR), and their roles in cotton's response to these stress factors. Furthermore, we explore the potential mechanisms and the crosstalk between different stress factors signaling pathways. We also examine the implications of stress-induced changes in antioxidant levels and enzyme activities for cotton productivity and breeding strategies. Additionally, we shed light on the unanswered questions, research gaps, and future perspectives in this field, paving the way for further investigations to enhance our understanding of cotton's antioxidant defenses and develop novel strategies for improving cotton stress tolerance and yield stability.

The resilient cotton plant: uncovering the effects of stresses on secondary metabolomics and its underlying molecular mechanisms.

Cotton is an important fiber crop cultivated around the world under diverse climate conditions and generates billions of dollars in annual revenue globally. Biotic and abiotic stresses have caused reduction in yield and productivity of cotton crops. In this review, we comprehensively analyzed and summarized the effect of biotic and abiotic stress on secondary metabolite production in cotton. The development of cotton varieties with improved tolerance against abiotic and biotic stress can play an important role in sustainable cotton production. Under stress conditions, plants develop a variety of defense mechanisms such as initiating signaling functions to upregulate defense responsive genes and accumulation of secondary metabolites. Understanding the impact of stress on secondary metabolite production in cotton is crucial for developing strategies to alleviate the negative effects of stress on crop yield and quality. Further, the potential industrial applications of these secondary metabolites in cotton, such as gossypol, could provide new opportunities for sustainable cotton production and the development of value-added products. Additionally, transgenic and genome-edited cotton cultivars can be developed to provide tolerance to both abiotic and biotic stress in cotton production.

Conservation and Divergence of Phosphoenolpyruvate Carboxylase Gene Family in Cotton.

Phosphoenolpyruvate carboxylase (PEPC) is an important enzyme in plants, which regulates carbon flow through the TCA cycle and controls protein and oil biosynthesis. Although it is important, there is little research on PEPC in cotton, the most important fiber crop in the world. In this study, a total of 125 PEPCs were identified in 15 Gossypium genomes. All PEPC genes in cotton are divided into six groups and each group generally contains one PEPC member in each diploid cotton and two in each tetraploid cotton. This suggests that PEPC genes already existed in cotton before their divergence. There are additional PEPC sub-groups in other plant species, suggesting the different evolution and natural selection during different plant evolution. PEPC genes were independently evolved in each cotton sub-genome. During cotton domestication and evolution, certain PEPC genes were lost and new ones were born to face the new environmental changes and human being needs. The comprehensive analysis of collinearity events and selection pressure shows that genome-wide duplication and fragment duplication are the main methods for the expansion of the PEPC family, and they continue to undergo purification selection during the evolutionary process. PEPC genes were widely expressed with temporal and spatial patterns. The expression patterns of PEPC genes were similar in G. hirsutum and G. barbadense with a slight difference. PEPC2A and 2D were highly expressed in cotton reproductive tissues, including ovule and fiber at all tested developmental stages in both cultivated cottons. However, PEPC1A and 1D were dominantly expressed in vegetative tissues. Abiotic stress also induced the aberrant expression of PEPC genes, in which PEPC1 was induced by both chilling and salinity stresses while PEPC5 was induced by chilling and drought stresses. Each pair (A and D) of PEPC genes showed the similar response to cotton development and different abiotic stress, suggesting the similar function of these PEPCs no matter their origination from A or D sub-genome. However, some divergence was also observed among their origination, such as PEPC5D was induced but PEPC5A was inhibited in G. barbadense during drought treatment, suggesting that a different organized PEPC gene may evolve different functions during cotton evolution. During cotton polyploidization, the homologues genes may refunction and play different roles in different situations.

Pulse Intake Improves Nutrient Density among US Adult Consumers.

The objective was to examine trends in pulse (dry beans, dry peas, chickpeas and lentils) intake over a 10-year period and to compare nutrient intakes of pulse consumers and non-consumers to better understand the impact of pulse consumption on diet quality in the US population. NHANES 2003-2014 data for respondents (≥19 years) with 2 days of intake was used to evaluate trends in pulse intake. Pulse consumers were identified as those NHANES respondents who consumed pulses on one or both days. Differences in energy adjusted nutrient intakes between non-consumers and consumers were assessed. There were no significant trends in pulse intakes for the total population or for pulse consumers over the 10-year period. In 2013-2014, approximately 27% of adults consumed pulses with an intake of 70.9 ± 2.5 g/day over 2 days, just slightly <0.5 cup equivalents/day. At all levels of consumption, consumers had higher (p < 0.01) energy adjusted intakes of fiber, folate, magnesium. Higher energy adjusted intakes for potassium, zinc, iron and choline and lower intakes of fat were observed for consumers than for non-consumers at intakes ≥69.4 ± 1.01 g/day. These data suggest that pulse consumption in the US population may result in better diet quality with diets that are more nutrient dense than those without pulses.

A standardised approach for determining heat tolerance in cotton using triphenyl tetrazolium chloride.

Improving the heat tolerance of cotton is a major concern for breeding programs. To address this need, a fast and effect way of quantifying thermotolerant phenotypes is required. Triphenyl tetrazolium chloride (TTC) based enzyme viability testing following high-temperature stress can be used as a vegetative heat tolerance phenotype. This is because when live cells encounter a TTC solution, TTC undergoes a chemical reduction producing a visible, insoluble red product called triphenyl formazan, that can be quantified spectrophotometrically. However, existing TTC based cell viability assays cannot easily be deployed at the scale required in a crop improvement program. In this study, a heat stress assay (HSA) based on the use of TTC enzyme viability testing has been refined and improved for efficiency, reliability, and ease of use through four experiments. Sampling factors that may influence assay results, such as leaf age, plant water status, and short-term cold storage, were also investigated. Experiments conducted in this study have successfully downscaled the assay and identified an optimal sampling regime, enabling measurement of large segregating populations for application in breeding programs. The improved HSA methodology is important as it is proposed that long-term improvements in cotton thermotolerance can be achieved through the concurrent selection of superior phenotypes based on the HSA and yield performance in hot environments. Additionally, a new way of interpreting both heat tolerance and heat resistance was developed, differentiating genotypes that perform well at the time of a heat stress event and those that maintain a similar performance level to a non-stressed control.

Does particulate matter along roadsides interfere with plant reproduction? A comparison of effects of different road types on Cichorium intybus pollen deposition and germination.

The roadside habitat can be challenging for plants, which must maintain normal biological processes despite an influx of airborne pollutants. While the effects of many gases on plants have been quantified, the impacts of particulate pollutants have been relatively less studied. This is especially true of field experiments where particle dispersion may be influenced by meteorology and roadway use. We examined chicory (Cichorium intybus L.) along roadsides in the Cincinnati, Ohio metropolitan area to assess particulate influence on plant pollination through stigmatic clogging. We compared flowers collected from plants situated along interstates, U.S. highways, state highways, and county roads as these different road-types vary in motor vehicle usage and thus should have varying levels of particulate deposition on flowers. We examined floral stigmas for total particulates, total pollen, and percentage of pollen tube germination to determine whether particulates may interfere with early reproductive processes. Our results suggest that there was minimal variation of particulate matter found on chicory stigmas among road-types. Furthermore, the deposition of particulates on stigmas based on road-type did not show a strong link to variation in pollen deposition and pollen germination. There was also no significant relationship between total particulate levels and pollen germination rates across all road types. Future studies should investigate other plant species that may be more sensitive to roadside pollution, such as economically important crops. Locations in which vehicle use is increasing and where pollutants are not regulated strictly should also be examined as the effects of airborne particulates in early plant reproduction would be expected to be more substantial in these areas.