Morphological Adaptations Research Articles

Host-specific monogeneans parasitizing freshwater fish: The ecology and evolution of host-parasite associations.

Monogenea (Platyhelminthes), mainly gill and fin ectoparasites of fish, are often recognized as host specific and morphologically and ecologically diverse. These parasites exhibit high species diversity at the level of host species or individual fish specimens. Using case studies, especially those widely performed in Dactylogyrus parasitizing cyprinoid fish, this article presents current knowledge on the ecology and evolution of congeneric gill monogeneans. The important aspects of the ecology of congeneric monogeneans are highlighted, in particular: host specificity expressed at several host levels (from strict specificity to phylogenetic specificity), microhabitat specificity expressed by restricted positions on fish gills to facilitate intraspecific mating, and the link between microhabitat preference and morphological adaptation (i.e., sclerotized structures of the haptor) or reproductive isolation. From the evolutionary perspective, this study focused on the processes of the speciation and diversification of congeneric monogeneans, highlighting the role of host switch as the most prominent coevolutionary event, accompanied in some cases mostly by intrahost speciation or cospeciation, as revealed by cophylogenetic studies. Here, important knowledge on evolutionary patterns of host specificity, microhabitat specificity, and morphological adaptation is presented. Host-specific monogeneans may represent an important tool for studying the historical biogeography of their hosts. Specifically, in the case of freshwater fish hosts exhibiting disjunctive distribution, they reflect both historical and contemporary contacts. The role of host-specific congeneric monogeneans in revealing historical intercontinental and intracontinental contacts between freshwater fish is highlighted. Finally, the importance of the role of genetic coadaptation, limiting the presence of host-specific monogeneans in hybrid fish, is emphasized.

Orthographic and Morphological Variation of Loanwords in the Arabic Vernaculars

The present article discusses the key orthographic and morphological modifications that Anglicisms and Gallicisms undergo beyond their adaptation in various Arabic vernaculars. At the level of orthography, the spelling of words with a two-consonant beginning, compound nouns and abbreviations is analyzed. The range of analyzed morphological categories includes gender and number for nouns, voice and mood for verbs. The need for a study is due to insufficient information about the above aspects of the adaptation of borrowings in Arabic dialects. For a detailed comparative analysis of various approaches to spelling and morphological adaptation, the author uses a questionnaire targeted for the dialect speakers. Based on the answers of 206 respondents from 18 Arab countries, it is concluded that the loanwords introduced via Arabic script preserve the source-language orthography. Borrowed abbreviations in participants’ answers mostly become acronyms. As for the gender of nouns, the participants tend to determine this morphological category relying on semantic analogy and phonetic similarity of endings. In matters of plural formation, suffixation remains the most popular way. However, in the case of inanimate nouns, up to a third of participants’ responses contain broken plurals. An analysis of borrowed verbs showed differences in the approaches of Arabic speakers from the Arab West and East in the adaptation of English and French lemmas and their subsequent conjugation. This circumstance allows us to conclude that the variability in adaptation is related to extralinguistic factors inherent in certain Arabic-speaking communities.

Effects of Different Feeding Frequencies on Broiler Chickens’ Growth Performance and Intestinal Villus Development

This experiment was conducted to determine the effects of feeding frequency on growth performance and development of small intestine in broiler chickens from 1 to 14 days of age. Forty Aber acres broiler chicks at 1 day old were randomly assigned to 4 treatments as follows - T1: feeding once daily (100 % diet at 6:30), T2: feeding twice daily (50 % diet at 6:30 and 18:30), T3: feeding 4 times per day (25 % diet at 6:30, 11:30, 16:30 and 21:30) and T4: feeding 6 times per day (16.67 % diet at 6:30, 9:30, 12:30, 15:30, 18:30 and 21:30). Chickens were fed with commercial broiler rations for 14 days. Growth performance parameters including BW, BW gain, FI and FCR were determined. Changes in intestinal villus morphology were examined by hematoxylin and eosin (H&E) dye staining. Results showed that chickens fed 4 and 6 times per day had lower (p < 0.05) BW, BW gain and FI when compared with chickens fed once daily, from 1 to 7 days of age. However, at 14 days of age, there were no significant differences in all parameters of growth performance. There were no changes in gross anatomy of the small intestine. Fixed feeding 4 and 6 times per day resulted in the villus height of the jejunum and ileum being higher (p < 0.05) than when feeding once a day. Feeding 6 times per day resulted in the highest villus density in jejunum among feed regimes. The results suggested that both once and multiple daily feedings were suitable approaches to achieve optimum growth performance for broiler chickens from 1 to 14 days of age. Fixed feeding 6 times per day being the most beneficial for improving intestinal villus development. HIGHLIGHTS Feeding frequency is one of feed restriction method in broilers management From 1 to 7 days of age feeding fed 4 and 6 times per day show lower growth performance than feeding once daily, but not for 14 days of age Fixed feeding 4 and 6 times per day present the villus height at jejunum and ileum higher than feeding once daily Fixed feeding 6 times per day is the most effective solution for enhancing intestinal villus development Here, the experiment demonstrates for the first time that the compensatory growth effects by frequently feeding is at least mediated through adaptation of villus morphology in the small intestine along with improved feed consumption GRAPHICAL ABSTRACT

Morphological and physiological adaptation of a desert shrub, Encelia farinosa, under drought stress

Water scarcity in arid and semi-arid regions affects ecosystem development. Therefore, elucidation of the mechanisms by which plant species in a given region respond to drought conditions may allow us to improve global vegetation. Encelia species are drought-tolerant and an important component of shrub communities in the arid and semi-arid regions of southern California, U.S.A.; these species are widely used for vegetation restoration in the region. This study aimed to investigate the morphological, and physiological responses in E. farinosa in relation to changes in soil properties under drought conditions. Plants were subjected to two levels of soil water regimes, drought and well-watered conditions (5% and 12% of gravimetric water content, respectively). After 3 months, above-ground biomass, basal diameter, leaf area, leaf and root relative water content, and root length were measured. The shoot:root ratio in dry mass and specific leaf area (SLA) were calculated. We also analyzed leaf and soil nutrients, including total C, N, and available P. In the drought treatment, E. farinosa showed significantly lower above-ground biomass, stem diameter, and shoot and root relative water content. Also, the drought treatment resulted in significantly lower leaf areas, while the SLA and root length were significantly higher. Leaf total C and N were higher in the drought treatment while leaf P was not affected by soil water content. The reduction in plant leaf area, root elongation and the increase in SLA under drought are known as drought avoidance strategies of plants, suggesting that E. farinosa hampers water loss by morphological regulations. Additionally, higher leaf content of C and N seems to be important for metabolic drought adaptation. Further research on osmotic adjustment and antioxidant defense systems will clarify the detailed drought tolerance mechanisms of E. farinosa in relation to C and N accumulation under drought conditions.

Transdisciplinary approaches for the study of cyanobacteria and cyanotoxins

Cyanobacteria, ancient aerobic and photoautotrophic prokaryotes, thrive in diverse ecosystems due to their extensive morphological and physiological adaptations. They play crucial roles in aquatic ecosystems as primary producers and resource providers but also pose significant ecological and health risks through blooms that produce harmful toxins, called cyanotoxins. The taxonomic affiliation of cyanobacteria has evolved from morphology-based methods to genomic analysis, which offers detailed structural and physiological insights that are essential for accurate taxonomic affiliation and monitoring. However, challenges posed by uncultured species have been extrapolated to the detection and quantification of cyanotoxins. Current advances in molecular biology and informatics improve the precision of monitoring and allow the analysis of groups of genes related to toxin production, providing crucial information for environmental biosafety and public health. Unfortunately, public genomic databases heavily underrepresent cyanobacteria, which limits the understanding of their diversity and metabolic capabilities. Despite the increasing availability of cyanobacterial genome sequences, research is still largely focused on a few model strains, narrowing the scope of genetic and metabolic studies. The challenges posed by cyanobacterial blooms and cyanotoxins necessitate improved molecular, cultivation, and polyphasic techniques for comprehensive classification and quantification, highlighting the need for advanced genomic approaches to better understand and manage cyanobacteria and toxins. This review explores the application of transdisciplinary approaches for the study of cyanobacteria and cyanotoxins focused on diversity analysis, population quantification, and cyanotoxin monitoring, emphasizing their genomic resources and their potential in the genomic mining of toxin-related genes.

Screening key sorghum germplasms for low-nitrogen tolerance at the seedling stage and identifying from the carbon and nitrogen metabolism.

Sorghum (Sorghum bicolor L.) can withstand drought and heat stress and efficiently utilize water and nutrients. However, the underlying mechanism of its tolerance to low-nitrogen (N) stress remains poorly understood. This study assessed low-N tolerance in 100 sorghum-inbred lines and identified those with exceptional resilience. Principal component analysis, Pearson's correlation, and Y value analysis were used to examine various seedling growth metrics, including plant and root dimensions, biomass, chlorophyll content, root N content, shoot N content, and root/shoot ratio. The genotypes were categorized into four distinct groups based on their respective Y values, revealing a spectrum from highly tolerant to sensitive. Low-N-tolerant sorghum lines maintained higher photosynthetic rates and exhibited increased enzymatic activities linked to carbon and N metabolism in the leaves and roots. Furthermore, low-N-tolerant genotypes had higher levels of key amino acids, including cystine, glycine, histidine, isoleucine, leucine, phenylalanine, threonine, and tyrosine, indicating a robust internal metabolic response to N deficiency. This study provides a comprehensive and reliable approach for the evaluation of sorghum tolerance to low-N environments, sheds light on its morphological and physiological adaptations, and provides valuable insights for future breeding programs and agricultural practices.

High-throughput phenotyping reveals multiple drought responses of wild and cultivated Phaseolinae beans.

Although drought resistance of a plant may be achieved through morphological, structural, physiological, cellular, and molecular adaptations, most studies remain limited to quantifying the effect of drought on biomass. Using a highthroughput phenotypic imaging system, we evaluated the drought resistance of 151 bean accessions (Phaseolinae; Fabaceae) in an explorative approach, by quantifying five different traits simultaneously: biomass, water use efficiency (WUE), relative water content (RWC), chlorophyll content (NDVI), and root/shoot ratio. Since crop wild relatives are important resources for breeding programs, we analyzed both wild and cultivated accessions, most of which have never been evaluated for drought resistance before. We demonstrate that the five traits are affected very differently by drought in the studied accessions, with significant correlations existing only between the biomass and WUE indicators (r=0.39), and between the RWC and NDVI indicators (r=0.40). When grouping accessions by subgenus or by species, large intraspecific and withinsubgenus variation was found. For this reason, we performed a cluster analysis, which grouped the accessions into five distinct clusters with similar response profiles. We also correlated the drought resistance for each accession to local climate variables at their original collection sites. The biomass, WUE, and RWC indicators were significantly correlated to annual precipitation (r=0.40, r=0.20, r=0.22, respectively), confirming that accessions from arid environments are generally more drought resistant. Our results demonstrate that the drought resistance of Phaseolinae beans is a multifaceted characteristic and cannot be simply quantified through biomass. Furthermore, the broader knowledge of the drought resistance of the accessions studied here may prove an invaluable resource for future crop production.

Morphological and anatomical adaptations of leaves of the Kuban - 86 clonal rootstock in the conditions of Dagestan

Morphological and anatomical adaptations of leaves of the Kuban - 86 clonal rootstock in the conditions of Dagestan

Locomotion and morphological adaptations in the glass lizard Ophiodes cf. fragilis (Raddi, 1820) (Squamata: Anguidae).

There are few studies related to the biological and ecological aspects of the glass snake, a limbless lizard and with a wide geographic distribution. The aim of this study was to analyze the locomotion mode of specimens of Ophiodes cf. fragilis in different substrates and to investigate the morphological adaptations associated with this type of behavior. We observed that the analyzed specimens presented slide-push locomotion modes and lateral undulation in different substrates, using their hind limbs to aid locomotion in three of the four substrates analyzed. The bones of the hind limbs (proximal - femur - and distal - tibia and fibula) were present and highly reduced and the femur is connected to a thin pelvic girdle. Our data support that hind limbs observed in species of this genus are reduced rather than vestigial. The costocutaneous musculature was macroscopically absent. This is the first study of locomotor behavior and morphology associated with locomotion in Ophiodes, providing important information for studies on morphological evolution in the genus.

Using linear measurements to diagnose the ecological habitat of Spinosaurus.

Much of the ecological discourse surrounding the polarising theropod Spinosaurus has centred on qualitative discussions. Using a quantitative multivariate data analytical approach on size-adjusted linear measurements of the skull, we examine patterns in skull shape across a range of sauropsid clades and three ecological realms (terrestrial, semi-aquatic, and aquatic). We utilise cluster analyses to identify emergent properties of the data which associate properties of skull shape with ecological realm occupancy. Results revealed terrestrial ecologies to be significantly distinct from both semi- and fully aquatic ecologies, the latter two were not significantly different. Spinosaurids (including Spinosaurus) plotted away from theropods in morphospace and close to both marine taxa and wading birds. The position of nares and the degree of rostral elongation had the greatest effect on categorisation. Comparisons of supervised (k-means) and unsupervised clustering demonstrated categorising taxa into three groups (ecological realms) was inappropriate and suggested instead that cluster division is based on morphological adaptations to feeding on aquatic versus terrestrial food items. The relative position of the nares in longirostrine taxa is associated with which skull bones are elongated. Rostral elongation is observed by either elongating the maxilla and the premaxilla or by elongating the maxilla only. This results in the nares positioned towards the orbits or towards the anterior end of the rostrum respectively, with implications on available feeding methods. Spinosaurids, especially Spinosaurus, show elongation in the maxilla-premaxilla complex, achieving similar functional outcomes to elongation of the premaxilla seen in birds, particularly large-bodied piscivorous taxa. Such a skull construction would bolster "stand-and-wait" predation of aquatic prey to a greater extent than serving other proposed feeding methods.

More than a name: Mid‐Cretaceous amber fossils link crickets and mole crickets (Orthoptera, Ensifera)

AbstractGrylloidea (crickets) and Gryllotalpoidea (mole crickets and ant crickets) are relatively ancient lineages within Orthoptera but their fossil records are not very rich. They are currently considered sister clades within the Gryllidea but with obvious differences in morphology and ecological adaptations. We report a new gryllidean family, †Pseudogryllotalpidae fam. nov. with three new genera and four new species, viz. †Pseudogryllotalpa scalprata gen. et sp. nov., †Unidigitus longialatus gen. et sp. nov., †Petilus zhengi gen. et sp. nov. and †Chunxiania fascia sp. nov. from the mid‐Cretaceous of northern Myanmar (ca. 99 million years ago). Their external and short ovipositors and their modified fossorial forelegs suggest a soil‐inhabiting preference. This new family exhibits a series of ‘intermediate’ character states between Grylloidea and Gryllotalpoidea and seems to be a ‘transitional’ fossil group linking these two superfamilies. This new family was resolved as a sister group of the extant Gryllotalpoidea and provides a new insight into the relationship and evolution of Grylloidea and Gryllotalpoidea.

RECEPTIVE ASSIMILATION OF FRENCH BORROWINGS INTO THE BASIC ENGLISH VOCABULARY

Objective. The objective of the article is to analyze the French borrowings come into the English language in the context of the receptive assimilation process; identify the stages of receptive assimilation; analyze the French loan-words during the process of borrowing, appropriate to each stage in order to enable effective intercultural research process connected with historical aspect of philological and linguistic studies. Methods. The main scientific results are obtained using two groups of methods: theoretical and statistical ones. The theoretical methods include: the method of theoretical generalization, which makes it possible to determine and nature of French borrowings’ receptive assimilation; problem- chronological ̶ for considering French borrowings of different periods in dynamics and distinguishing periods; methods of extrapolation ̶ to justify provisions regarding the understanding of the influence of historical experience on the vocabulary of the English language; the problem- genetic method ̶ to justify the provisions regarding the analysis of problems that may hinder effective intercultural research process connected with historical aspect of philological and linguistic studies. The statistical group includes verification of received information by processing and comparing data published in various scientific sources. Results. The theoretical analysis of the nature of the French borrowings makes it possible to identify the stages of receptive assimilation that enable effective intercultural studies in the fields of linguistics, philology, and terminology. The conceptual and categorical apparatus of the study containing the following terms as: “French borrowings” and “receptive assimilation” is formed. The stages of receptive assimilation of French borrowings into the English language are defined. Interpretation and analysis of the genesis of possible stages of lexical borrowings will lead to successful management of the educational process for philology, lexicology and language history students. The generalized seven typical stages of receptive assimilation are distinguished as follows: borrowing; integration; phonological adaptation; morphological adaptation; semantic shift; naturalization; and complete assimilation.

Impacts of Water Logging on Soil Microbial Intentions and Mung Bean (Vigna radiata L.) Physiology

The mung bean (Vigna radiata L.) is an important pulse crop known for its high protein content and adaptability to tropical and subtropical regions, particularly in Asia. Despite of their importance as a source of protein, most noticeably that, waterlogging negatively affects their growth and yield. Waterlogging, resulting from factors like compacted soil and excessive irrigation, leads to hypoxic conditions and negatively affects various physiological and morphological aspects of mung bean plants. The impact of waterlogging on mung beans at different growth stages emphasises its detrimental effects on root growth, leaf area, chlorophyll content, photosynthesis, and biomass. Waterlogging disrupts nutrient uptake, causing deficiencies and hindering overall plant adaptation. The molecular responses and metabolic changes in mung beans under waterlogging stress can upset the shift to anaerobic metabolism and the synthesis of specific proteins. Microbial interactions in the rhizosphere soil and their influence on mung bean growth during waterlogging also play an important role in mung bean growth and yield. Tolerance mechanisms, including morphological adaptations and physiological changes, are explored, offering insights into selecting tolerant genotypes. Agronomic strategies, such as the use of cytokinin and gibberellin acid used for mitigating waterlogging effects and enhancing mung bean resilience.

Hydrodynamic and Morphological Adaptation of Two Consecutive Sharp Bends of the Middle Yangtze River to Upstream Damming

AbstractIt remains an open question how the hydrodynamics and morphology in sharp meander bends adapt to the changes in flow and sediment conditions induced by upstream damming. This study reports a comprehensive investigation into the morphological changes, patterns of mean and secondary flows and sediment transport around two consecutive sharp bends in the Middle Yangtze River (MYR), and explains these changes from the viewpoint of flow‐sediment transport‐morphology interaction based on field measurements. With the Three Gorges Project operation, the MYR suffered a remarkable channel degradation due to a sudden decrease of incoming sediment discharge. The point bars were removed, and outer‐bank benches (OBB) formed upstream of the bend apices, which resulted in quite different flow and sediment transport patterns in the bends. The highest velocity zones and center‐region cells of secondary flow were more toward the inner bank due to the lack of point bars, and the outward migration of momentum was delayed. Flow recirculation zones were observed over the OBBs, covering 12%–58% of the channel width. The transport rates of suspended load accounted for 98% of the total sediment load, and the outward shift of the highest transport rate zone was confined by the OBBs, which reduced the effective width of sediment transport. These changes in flow and sediment transport re‐inforced the morphological changes around the sharp bends: the velocity redistribution and evolution of scour factor lagged more behind planform curvature, which further promoted the erosion of point bars and the development of OBB.

Reversible Host-Guest Crosslinks in Supramolecular Hydrogels for On-Demand Mechanical Stimulation of Human Mesenchymal Stem Cells.

Stem cells are regulated not only by biochemical signals but also by biophysical properties of extracellular matrix (ECM). The ECM is constantly monitored and remodeled because the fate of stem cells can be misdirected when the mechanical interaction between cells and ECM is imbalanced. A well-defined ECM model for bone marrow-derived human mesenchymal stem cells (hMSCs) based on supramolecular hydrogels containing reversible host-guest crosslinks is fabricated. The stiffness (Young's modulus E) of the hydrogels can be switched reversibly by altering the concentration of non-cytotoxic, free guest molecules dissolved in the culture medium. Fine-adjustment of substrate stiffness enables the authors to determine the critical stiffness level E* at which hMSCs turn the mechano-sensory machinery on or off. Next, the substrate stiffness across E* is switched and the dynamic adaptation characteristics such as morphology, traction force, and YAP/TAZ signaling of hMSCs are monitored. These data demonstrate the instantaneous switching of traction force, which is followed by YAP/TAZ signaling and morphological adaptation. Periodical switching of the substrate stiffness across E* proves that frequent applications of mechanical stimuli drastically suppress hMSC proliferation. Mechanical stimulation across E* level using dynamic hydrogels is a promising strategy for the on-demand control of hMSC transcription and proliferation.

Physio-anatomical modifications and element allocation pattern in Alternanthera tenella Colla. associated with phytoextraction of chromium.

Intensive industrial activities have elevated chromium (Cr) concentrations in the environment, particularly in soil and water, posing a significant threat due to its cytotoxic and carcinogenic properties. Phytoremediation has emerged as a sustainable and economical alternative for detoxifying pollutants. In this context, an attempt has been made to assess the efficacy of Cr remediation by the invasive plant Alternanthera tenella Colla. The study investigated morphological, anatomical, and physiological adaptations in plant tissues in response to 240µM of K2Cr2O7, considering elemental distribution patterns and bioaccumulation potential. Growth parameter assessments revealed a notable 50% reduction in root elongation and biomass content; however, the plant exhibited a comparatively higher tolerance index (47%) under Cr stress. Chromium significantly influenced macro and micro-elemental distribution in plant tissues, particularly in roots and leaves. Structural modifications, including changes in the thickness and diameter of xylem walls in the root, stem, and leaf tissues of Cr-treated A. tenella, were observed. Distinct cell structural distortions and Cr deposit inclusions in the xylem wall and inner parenchyma cells were distinct. Under Cr stress, there was a reduction in pigment content and metabolites such as proteins and soluble sugars, while proline, phenol, and malondialdehyde showed a twofold increase. The concentration of Cr was higher in the shoots of A. tenella (185.7mg/kg DW) than in the roots (179.625mg/kg DW). With a high BCFroot value (16.23) and TF > 1, coupled with effective mechanisms to cope with metal stress, A. tenella emerges as an ideal candidate for chromium phytoextraction.

Hotter-is-not-better: A study on the thermal response of a winter active and nocturnal beetle

While there are numerous examples of thermogenesis processes in poikilothermic insects that maintain a stable temperature for a certain time and in certain parts of the body, there is a lack of information on ectothermic insect species capable of remaining active under “cold” conditions that would be challenging for other species. Such a thermal strategy would imply the existence of a metabolism that can operate at different temperatures without the need to increase body temperature when experiencing cold environmental conditions. This “hotter-is-not-better“ thermal strategy is considered ancestral and conjectured to be linked to the origin and evolution of endothermy. In this study, we examined the thermal performance of a large-bodied dung beetle species (Chelotrupes momus) capable of being active during the winter nights in the Iberian Mediterranean region. Field and laboratory results were obtained using thermocamera records, thermocouples, data loggers and spectrometers that measured ultraviolet, visible and near-infrared wavelengths. The thermal data clearly indicated that this species can remain active at a body temperature of approximately 6 °C without the need to warm its body above ambient temperature. Comparing the spectrophotometric data of the species under study with that from other previously examined dung beetle species indicated that the exoskeleton of this particular species likely enhances the absorption of infrared radiation, thereby implying a dual role of the exoskeleton in both heat acquisition and heat dissipation. Taken together, these results suggest that this species has morphological and metabolic adaptations that enable life processes at temperatures that are typically unsuitable for most insect species in the region.

Metacyclogenesis as the Starting Point of Chagas Disease.

Chagas disease is a neglected infectious disease caused by the protozoan Trypanosoma cruzi, primarily transmitted by triatomine vectors, and it threatens approximately seventy-five million people worldwide. This parasite undergoes a complex life cycle, transitioning between hosts and shifting from extracellular to intracellular stages. To ensure its survival in these diverse environments, T. cruzi undergoes extreme morphological and molecular changes. The metacyclic trypomastigote (MT) form, which arises from the metacyclogenesis (MTG) process in the triatomine hindgut, serves as a crucial link between the insect and human hosts and can be considered the starting point of Chagas disease. This review provides an overview of the current knowledge regarding the parasite's life cycle, molecular pathways, and mechanisms involved in metabolic and morphological adaptations during MTG, enabling the MT to evade the immune system and successfully infect human cells.

The transcription factor PtoMYB142 enhances drought tolerance in Populus tomentosa by regulating gibberellin catabolism.

Drought stress caused by global warming has resulted in significant tree mortality, driving the evolution of water conservation strategies in trees. Although phytohormones have been implicated in morphological adaptations to water deficits, the molecular mechanisms underlying these processes in woody plants remain unclear. Here, we report that overexpression of PtoMYB142 in Populus tomentosa results in a dwarfism phenotype with reduced leaf cell size, vessel lumen area, and vessel density in the stem xylem, leading to significantly enhanced drought resistance. We found that PtoMYB142 modulates gibberellin catabolism in response to drought stress by binding directly to the promoter of PtoGA2ox4, a GA2-oxidase gene induced under drought stress. Conversely, knockout of PtoMYB142 by the CRISPR/Cas9 system reduced drought resistance. Our results show that the reduced leaf size and vessel area, as well as the increased vessel density, improve leaf relative water content and stem water potential under drought stress. Furthermore, exogenous GA3 application rescued GA-deficient phenotypes in PtoMYB142-overexpressing plants and reversed their drought resistance. By suppressing the expression of PtoGA2ox4, the manifestation of GA-deficient characteristics, as well as the conferred resistance to drought in PtoMYB142-overexpressing poplars, was impeded. Our study provides insights into the molecular mechanisms underlying tree drought resistance, potentially offering novel transgenic strategies to enhance tree resistance to drought.

Molecular insights and omics-based understanding of plant-microbe interactions under drought stress.

The detrimental effects of adverse environmental conditions are always challenging and remain a major concern for plant development and production worldwide. Plants deal with such constraints by physiological, biochemical, and morphological adaptations as well as acquiring mutual support of beneficial microorganisms. As many stress-responsive traits of plants are influenced by microbial activities, plants have developed a sophisticated interaction with microbes to cope with adverse environmental conditions. The production of numerous bioactive metabolites by rhizospheric, endo-, or epiphytic microorganisms can directly or indirectly alter the root system architecture, foliage production, and defense responses. Although plant-microbe interactions have been shown to improve nutrient uptake and stress resilience in plants, the underlying mechanisms are not fully understood. "Multi-omics" application supported by genomics, transcriptomics, and metabolomics has been quite useful to investigate and understand the biochemical, physiological, and molecular aspects of plant-microbe interactions under drought stress conditions. The present review explores various microbe-mediated mechanisms for drought stress resilience in plants. In addition, plant adaptation to drought stress is discussed, and insights into the latest molecular techniques and approaches available to improve drought-stress resilience are provided.