The formation of shoots plays a pivotal role in plant organogenesis and productivity. Despite its significance, the underlying molecular mechanism of de novo regeneration has not been extensively ...elucidated in Capsicum annuum 'Dempsey', a bell pepper cultivar. To address this, we performed a comparative transcriptome analysis focusing on the differential expression in C. annuum 'Dempsey' shoot, callus, and leaf tissue. We further investigated phytohormone-related biological processes and their interacting genes in the C. annuum 'Dempsey' transcriptome based on comparative transcriptomic analysis across five species.
We provided a comprehensive view of the gene networks regulating shoot formation on the callus, revealing a strong involvement of hypoxia responses and oxidative stress. Our comparative transcriptome analysis revealed a significant conservation in the increase of gene expression patterns related to auxin and defense mechanisms in both callus and shoot tissues. Consequently, hypoxia response and defense mechanism emerged as critical regulators in callus and shoot formation in C. annuum 'Dempsey'. Current transcriptome data also indicated a substantial decline in gene expression linked to photosynthesis within regenerative tissues, implying a deactivation of the regulatory system governing photosynthesis in C. annuum 'Dempsey'.
Coupled with defense mechanisms, we thus considered spatial redistribution of auxin to play a critical role in the shoot morphogenesis via primordia outgrowth. Our findings shed light on shoot formation mechanisms in C. annuum 'Dempsey' explants, important information for regeneration programs, and have broader implications for precise molecular breeding in recalcitrant crops.
This study examined longitudinal changes in coping and defense mechanisms in an age- and gender-stratified sample of 392 European American adults. Nonlinear age-related changes were found for the ...coping mechanisms of sublimation and suppression and the defense mechanisms of intellectualization, doubt, displacement, and regression. The change trajectories for sublimation and suppression showed that their use increased from adolescence to late middle age and early old age and remained mostly stable into late old age. The change trajectory for intellectualization showed that the use of this defense mechanism increased from adolescence to middle age, remained stable until late midlife, and started to decline thereafter. The defense mechanisms of doubt, displacement, and regression showed decreases from adolescence until early old age, with increases occurring again after the age of 65. Linear age-related decreases were found for the coping mechanism of ego regression and the defense mechanisms of isolation and rationalization. Gender and socioeconomic status were associated with the mean levels of several coping and defense mechanisms but did not moderate age-related changes. Increases in ego level were associated with increased use of the defense mechanism intellectualization and decreased use of the defense mechanisms of doubt and displacement. Overall, these findings in a European American sample suggest that most individuals showed development in the direction of more adaptive and less maladaptive coping and defense strategies from adolescence until late middle age or early old age. However, in late old age this development was reversed, presenting potential challenges to the adaptive capacity of older adults.
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CEKLJ, FFLJ, NUK, ODKLJ, PEFLJ
Summary
Root microbiota composition shifts during the development of most annual plants. Although some perennial plants can live for centuries, the host–microbiome partnerships and interaction ...mechanisms underlying their longevity remain unclear.
To address this gap, we investigated age‐related changes in the root metabolites, transcriptomes, and microbiome compositions of 1‐ to 35‐yr‐old Populus tomentosa trees.
Ten co‐response clusters were obtained according to their accumulation patterns, and members of each cluster displayed a uniform and clear pattern of abundance. Multi‐omics network analysis demonstrated that the increased abundance of Actinobacteria with tree age was strongly associated with the flavonoid biosynthesis. Using genetic approaches, we demonstrate that the flavonoid biosynthesis regulator gene Transparent Testa 8 is associated with the recruitment of flavonoid‐associated Actinobacteria. Further inoculation experiments of Actinobacteria isolates indicated that their colonization could significantly improve the host's phenotype. Site‐directed mutagenesis revealed that the hyBl gene cluster, involved in biosynthesis of an aminocyclitol hygromycin B analog in Streptomyces isolate bj1, is associated with disease suppression.
We hypothesize that interactions between perennial plants and soil microorganisms lead to gradual enrichment of a subset of microorganisms that may harbor a wealth of currently unknown functional traits.
Summary
Algal viruses are important contributors to carbon cycling, recycling nutrients and organic material through host lysis. Although viral infection has been described as a primary mechanism of ...phytoplankton mortality, little is known about host defense responses.
We show that viral infection of the bloom‐forming, planktonic diatom Chaetoceros socialis induces the mass formation of resting spores, a heavily silicified life cycle stage associated with carbon export due to rapid sinking.
Although viral RNA was detected within spores, mature virions were not observed. ‘Infected’ spores were capable of germinating, but did not propagate or transmit infectious viruses.
These results demonstrate that diatom spore formation is an effective defense strategy against viral‐mediated mortality. They provide a possible mechanistic link between viral infection, bloom termination, and mass carbon export events and highlight an unappreciated role of viruses in regulating diatom life cycle transitions and ecological success.
Cotton has lost many ancestral defensive traits against key invertebrate pests. This is suggested by the levels of resistance to some pests found in wild cotton genotypes as well as in cultivated ...landraces and is a result of domestication and a long history of targeted breeding for yield and fiber quality, along with the capacity to control pests with pesticides. Genetic modification (GM) allowed integration of toxins from a bacteria into cotton to control key Lepidopteran pests. Since the mid-1990s, use of GM cotton cultivars has greatly reduced the amount of pesticides used in many cotton systems. However, pests not controlled by the GM traits have usually emerged as problems, especially the sucking bug complex. Control of this complex with pesticides often causes a reduction in beneficial invertebrate populations, allowing other secondary pests to increase rapidly and require control. Control of both sucking bug complex and secondary pests is problematic due to the cost of pesticides and/or high risk of selecting for pesticide resistance. Deployment of host plant resistance (HPR) provides an opportunity to manage these issues in GM cotton systems. Cotton cultivars resistant to the sucking bug complex and/or secondary pests would require fewer pesticide applications, reducing costs and risks to beneficial invertebrate populations and pesticide resistance. Incorporation of HPR traits into elite cotton cultivars with high yield and fiber quality offers the potential to further reduce pesticide use and increase the durability of pest management in GM cotton systems. We review the challenges that the identification and use of HPR against invertebrate pests brings to cotton breeding. We explore sources of resistance to the sucking bug complex and secondary pests, the mechanisms that control them and the approaches to incorporate these defense traits to commercial cultivars.
Summary
Innate immunity is a semi‐specific and widely distributed form of immunity, which represents the first line of defence against pathogens. This type of immunity is critical to maintain ...homeostasis and prevent microbe invasion, eliminating a great variety of pathogens and contributing with the activation of the adaptive immune response. The components of innate immunity include physical and chemical barriers, humoral and cell‐mediated components, which are present in all jawed vertebrates. The understanding of innate defence mechanisms in non‐mammalian vertebrates is the key to comprehend the general picture of vertebrate innate immunity and its evolutionary history. This is also essential for the identification of new molecules with applications in immunopharmacology and immunotherapy. In this review, we describe and discuss the main elements of vertebrate innate immunity, presenting core findings in this field and identifying areas that need further investigation.
Mosquito-borne diseases are associated with major global health burdens. Aedes spp. and Culex spp. are primarily responsible for the transmission of the most medically important mosquito-borne ...viruses, including dengue virus, West Nile virus and Zika virus. Despite the burden of these pathogens on human populations, the interactions between viruses and their mosquito hosts remain enigmatic. Viruses enter the midgut of a mosquito following the mosquito's ingestion of a viremic blood meal. During infection, virus recognition by the mosquito host triggers their antiviral defense mechanism. Of these host defenses, activation of the RNAi pathway is the main antiviral mechanism, leading to the degradation of viral RNA, thereby inhibiting viral replication and promoting viral clearance. However, whilst antiviral host defense mechanisms limit viral replication, the mosquito immune system is unable to effectively clear the virus. As such, these viruses can establish persistent infection with little or no fitness cost to the mosquito vector, ensuring life-long transmission to humans. Understanding of the mosquito innate immune response enables the discovery of novel antivectorial strategies to block human transmission. This review provides an updated and concise summary of recent studies on mosquito antiviral immune responses, which is a key determinant for successful virus transmission. In addition, we will also discuss the factors that may contribute to persistent infection in mosquito hosts. Finally, we will discuss current mosquito transmission-blocking strategies that utilize genetically modified mosquitoes and Wolbachia-infected mosquitoes for resistance to pathogens.
Arbuscular mycorrhizal fungi (AMF) are widely distributed soil-borne microorganisms, which have a symbiotic relationship with several terrestrial plants. They play a key role in plant growth ...promotion and development, plant nutrient homeostasis, soil nutrient management, and induction of plant defense mechanisms against pest infestation and disease incidences. This interaction of AMF with rice plants has been studied in great detail, providing distinct perspectives on the natural basis of nutrient transport, stress management, improvement of soil health, and induction of systemic plant resistance. This review highlights the responses of (i) AMF interaction with rice plants, (ii) AMF colonization and sporulation potential in rice rhizosphere, (iii) AMF species as a source of inoculum for rice production, (iv) AMF for rice plant maintenance and durability, and (v) AMF responses to other soil microorganisms. Additionally, a new class of phytohormones known as strigolactone (SLs) has been briefly described covering the various forms of analogs, isomers, and membrane transporters. The role of SLs in pre-symbiotic molecular talks, induction of energy metabolism in mitochondria, spore germination, stimulation of hyphal branches, and the relationships of SLs synthesis with soil nutrient content provides in-depth insights into the mechanisms involved in improving AMF interactions with rice plants.
The aquaculture industry has dramatically developed during the last two decades. However, this development has, in some cases, resulted in environmental degradation, emergence of diseases, and low ...productivity. The need for improving disease resistance, growth performance, feed efficiency, and safe aquatic production for human consumption has stimulated development and applications of probiotics in aquaculture. Probiotics used in aquaculture include genera of Bacillus, Lactobacillus, Enterococcus, and Carnobacterium, and yeast. However, most of these probiotics are derived from terrestrial sources and not from the environment in which the aquatic animals live or the host animal. The use of "host-associated probiotics" has gained attention, as they offer an alternative strategy within aquaculture, which per se is dependent on the use of terrestrial microorganisms. The benefits of host-associated probiotics include improved growth performance, feed value, enzymatic contribution to digestion, inhibit adherence, and colonization of pathogenic microorganisms in the gastrointestinal tract, increase hematological parameters, and immune response. The present review addressed insight into the application of host-associated probiotics within aquaculture, with special focus on their immunomodulatory and growth enhancing effects. Furthermore, the current review address research gaps and issues that merit further investigations.
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