Search Results (106)

Fungi, from saprophytes to pathogens, face predictable daily fluctuations in light, temperature, humidity, and nutrient availability. To cope, they have evolved an internal circadian clock that confers a major adaptive advantage. This review critically synthesizes current knowledge on the molecular architecture and physiological relevance of fungal circadian systems, moving beyond the canonical Neurospora crassa model to explore the broader phylogenetic diversity of timekeeping mechanisms. We examine the core transcription-translation feedback loop (TTFL) centered on the FREQUENCY/WHITE COLLAR (FRQ/WCC) system and contrast it with divergent and non-canonical oscillators, including the metabolic rhythms of yeasts and the universally conserved peroxiredoxin (PRX) oxidation cycles. A central theme is the clock’s role in gating cellular defenses against oxidative, osmotic, and nutritional stress, enabling fungi to anticipate and withstand environmental insults through proactive regulation. We provide a detailed analysis of chrono-pathogenesis, where the circadian control of virulence factors aligns fungal attacks with windows of host vulnerability, with a focus on experimental evidence from pathogens like Botrytis cinerea, Fusarium oxysporum, and Magnaporthe oryzae. The review explores the downstream pathways—including transcriptional cascades, post-translational modifications, and epigenetic regulation—that translate temporal signals into physiological outputs such as developmental rhythms in conidiation and hyphal branching. Finally, we highlight critical knowledge gaps, particularly in understudied phyla like Basidiomycota, and discuss future research directions. This includes the exploration of novel clock architectures and the emerging, though speculative, hypothesis of “chrono-therapeutics”—interventions designed to disrupt fungal clocks—as a forward-looking concept for managing fungal infections. Full article

Mango is highly sensitive to heat stress, which directly affects the yield and quality. The extreme heat waves of 2024, with temperatures reaching 41–47 °C over 25 days, caused significant impacts on sensitive cultivars. The impact of heat waves on ten commercial cultivars from subtropical regions viz.,‘Dashehari’, ‘Langra’, ‘Chausa’, ‘Bombay Green’, ‘Himsagar’, ‘Amrapali’, ‘Mallika’, ‘Sharda Bhog’, ‘Kesar’, and ‘Rataul’, and thirteen selected elite hybrids H-4208, H-3680, H-4505, H-3833, H-4504, H-1739, H-3623, H-1084, H-4264, HS-01, H-949, H-4065, and H-2805, is reported. The predominant effects that were observed include the following: burning symptoms or blackened tips, surrounded by a yellow halo, with premature ripening in affected parts and, in severe cases, tissue mummification. Among commercial cultivars, viz., ‘Amrapali’ (25%), ‘Mallika’ (30%), ‘Langra’ (30%), ‘Dashehari’ (50%), and ‘Himsagar’ and ‘Bombay Green’ had severe impacts, with ~80% of fruits being affected, followed by ‘Sharda Bhog’. In contrast, mid-maturing cultivars like ‘Kesar’, ‘Rataul’, and late-maturing elite hybrids, which were immature during the stress period, showed no symptoms, indicating they are tolerant. Biochemical analyses revealed significantly elevated total soluble solids (TSS > 25 °B) in affected areas of sensitive genotypes compared to non-affected tissues and tolerant genotypes. Aroma profiling indicated variations in compounds such as caryophyllene and humulene between affected and unaffected parts. The study envisages that the phenological maturity scales are indicators for the selection of climate-resilient mango varieties/hybrids and shows potential for future breeding programs. Full article

In wet subtropical environments, perennial groundcovers are common in horticultural plantations to protect the soil from erosion. However, there has been little investigation into whether seeding annual cover crops into the perennial groundcovers provides additional soil services including carbon and nutrient cycling in these systems. To investigate this, farmer participatory field trials were conducted in commercial avocado, macadamia, and coffee plantations in the wet Australian subtropics. Cover crops were direct-seeded into existing inter-row groundcovers in winter (cool season cover crops), and into the same plots the following summer (warm season cover crops). Inter-row biomass was quantified at the end of winter and summer in the control (no cover crop) and cover crops treatments. Soil carbon and nutrient cycling parameters including hot water extractable carbon, water soluble carbon, autoclavable citrate-extractable protein and soil enzyme activities were quantified every two months from early spring (September) 2021 to late autumn (May) 2022. Seeded cover crops produced 500 to 800 kg ha⁻¹ more total inter-row biomass over winter at the avocado coffee sites, and 3000 kg ha⁻¹ biomass in summer at the coffee site. However, they had no effect on biomass production in either season at the macadamia site. Soil functional parameters changed with season (i.e., time of sampling), with few significant effects of cover crop treatments on soil function parameters across the three sits. Growing a highly productive annual summer cover crop at the coffee site led to suppression and death of perennial groundcovers, exposing bare soil in the inter-row by 3 weeks after termination of the summer cover crop. Annual cover crops seeded into existing perennial groundcovers in tree crop systems had few significant impacts on soil biological function over the 12-month period, and their integration needs careful management to avoid investment losses and exacerbating the risk of soil erosion on sloping lands in the wet subtropics. Full article

Banana is a commercially important crop widely cultivated in tropical and subtropical regions, but its cultivation in the canal command basins is challenged due to the development of waterlogged sodic soils. The present study aimed to induce sodicity tolerance through the integration of secondary metabolites in the plants during the tissue culture organogenesis phase. Secondary-metabolite-treated plants were assessed for their performance in the waterlogged sodic soil areas of Samesee block in Lucknow district of Uttar Pradesh, India. Metabolite-treated (MT) plants exhibited significantly better growth and yield compared to untreated control (UTC) plants. Key physiological enhancements in MT plants included increased activities of defense-related enzymes superoxide dismutase (SOD), phenylalanine ammonia lyase (PAL), peroxidase (POD), and proline along with a reduced Na⁺/K⁺ ratio. The metabolic profile of MT plants showed higher expression of antioxidants, phenolic compounds, and flavonoids. MT plants exhibited production of the metabolites such as trihydroxy methylene–di-oxyflavone, rush flavanone, rutin, anthocyanins, neodiosmin, arachidonic acid, and trigalloyl-HHDP-glucose, which belongs to the subclasses of flavonoids, anthocyanins, and sugar alcohols. Consequently, MT plants produced a significantly higher yield (20.85 kg per plant) compared to UTC plants (8.35 kg) and greater biomass. These results suggest that treatments using secondary metabolite extracted from salt-tolerant bacteria can be used as an effective strategy for enhancing sodicity tolerance in banana plants, contributing to sustainable production and economic viability in waterlogged sodic soil conditions. Full article

Citrus commercial species are the most important fruit crops in the world; however, their cultivation is seriously threatened by the fast dispersion of emerging diseases, including Huanglongbing (HLB) citrus greening. HLB disease is vectored by psyllid vectors and associated with phloem-limited α-proteobacteria belonging to the Candidatus Liberibacter genus. Climatic change and trade globalization have led to the rapid spread of HLB from its origin center in Southeast Asia, causing a great economic impact in the main production areas, including East Asia (China), the Mediterranean basin, North America (the United States), and Latin America (Brazil and Mexico). Despite important advances to understand the HLB epidemiology, Candidatus Liberibacter genetics, psyllid vector control, the molecular citrus–Candidatus Liberibacter interaction, and the development of integral disease management strategies, the study areas have been mostly restricted to high-tech-producing countries. Thus, in this review, we provide an overview of the epidemiology, distribution, genetic diversity, management aspects, and omics analysis of HLB in Latin America, where this information to date is limited. Full article

Soil salinisation is threatening crop sustainability worldwide, mainly due to anthropogenic climate change. Molecular mechanisms developed to counteract salinity have been intensely studied in model plants. Nevertheless, the economically relevant olive tree (Olea europaea subsp. europaea L.), being highly exposed to soil salinisation, deserves a specific review to extract the recent genomic advances that support the known morphological and biochemical mechanisms that make it a relative salt-tolerant crop. A comprehensive list of 98 olive cultivars classified by salt tolerance is provided, together with the list of available olive tree genomes and genes known to be involved in salt response. Na⁺ and Cl^– exclusion in leaves and retention in roots seem to be the most prominent adaptations, but cell wall thickening and antioxidant changes are also required for a tolerant response. Several post-translational modifications of proteins are emerging as key factors, together with microbiota amendments, making treatments with biostimulants and chemical compounds a promising approach to enable cultivation in already salinised soils. Low and high-throughput transcriptomics and metagenomics results obtained from salt-sensitive and -tolerant cultivars, and the future advantages of engineering specific metacaspases involved in programmed cell death and autophagy pathways to rapidly raise salt-tolerant cultivars or rootstocks are also discussed. The overview of bioinformatic tools focused on olive tree, combined with machine learning approaches for studying plant stress from a multi-omics perspective, indicates that the development of salt-tolerant cultivars or rootstocks adapted to soil salinisation is progressing. This could pave the way for ‘smart oliviculture’, promoting more productive and sustainable practices under salt stress. Full article

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), is recognized as one of the most devastating diseases affecting banana cultivation worldwide. In India, Foc extensively affects Malbhog banana (AAB genomic group) production. In this study, we isolated 25 Foc isolates from wilt-affected Malbhog plantations inIndia. A pathogenicity test confirmed the identity of these isolates as Foc, the primary causative agent of wilt in bananas. The morpho-cultural characterization of Foc isolates showed large variations in colony morphological features, intensity, and pattern of pigmentation, chlamydospores, and conidial size. The molecular identification of these isolates using Race1- and Race4-specific primers established their identity as Race1 of Foc, with the absence of Tropical Race 4 of Foc. For a more comprehensive understanding of the genetic diversity of Foc isolates, we employed ISSR molecular typing, which revealed five major clusters. About 96% of the diversity within the Foc population indicated the presence of polymorphic loci in individuals of a given population evident from the results of Nei’s genetic diversity, Shannon’s information index, and the polymorphism information content values, apart from the analysis of molecular variance (AMOVA). The current findings provide significant insights toward the detection of Foc variants and, consequently, the deployment of effective management practices to keep the possible epidemic development of disease under control along the Malbhog banana growing belts of northeast India. Full article

Ambrosia beetles bore into trees, excavating galleries where they farm fungi as their sole source of nutrition. These mutualistic fungi typically do not cause significant damage to host trees; however, since their invasion into the U.S., the beetle Xyleborus glabratus has vectored its fungal partner, Harringtonia lauricola, which has acted as a devastating plant pathogen resulting in the deaths of over 500 million trees. Here, we show differences in the mycangial colonization of the indigenous X. affinis ambrosia beetle by H. lauricola, and the native fungal species, H. aguacate and Raffaelea arxii. While X. affinis was a good host for H. lauricola, the related ambrosia beetle, X. ferrugineus, was only marginally colonized by H. lauricola. X. affinis beetles neither fed on, nor were colonized by, the distantly related fungus, Magnaporthe oryzae. Mycangial colonization was affected by the nutritional state of the fungus. A novel method for direct quantification of mycangial contents based on image cell cytometry was developed and validated. The method was used to confirm mycangial colonization and demonstrate alternating fungal partner switching, which showed significant variation and dynamic turnover. X. affinis pre-oral mycangial pouches were visualized using fluorescent and light microscopy, revealing that newly emerged pupae displayed uncolonized mycangia prior to feeding, whereas beetles fed H. lauricola contained single-celled fungi within 6 h post-feeding. Mixed populations of fungal cells were seen in the mycangia of beetles following alternating colonization. Nuclear counter-staining revealed insect cells surrounding the mycangia. These data highlight variation and specificity in ambrosia beetle–fungal pairings and provide a facile method for direct quantification of mycangial contents. Full article

The host response to S. Typhimurium infection can be post-transcriptionally regulated by miRNAs. In this study, we investigated the role of miR-215 using both in vivo porcine infection models and in vitro intestinal epithelial cell lines. Several miRNAs were found to be dysregulated in the porcine ileum during infection with wild-type and SPI2-defective mutant strains of S. Typhimurium, with some changes being SPI2-dependent. Notably, miR-215 was significantly downregulated during infection. To explore its functional role, gain-of-function experiments were performed by transfecting porcine intestinal epithelial cells (IPEC-J2) with a miR-215-5p mimic, followed by label-free quantitative (LFQ) proteomic analysis. This analysis identified 157 proteins, of which 35 were downregulated in response to miR-215 overexpression, suggesting they are potential targets of this miRNA. Among these, E2 small ubiquitin-like modifier (SUMO)-conjugating enzyme UBC9 and E3 ubiquitin-ligase HUWE1 were identified as key targets, both of which are upregulated during S. Typhimurium infection. The miR-215-mediated downregulation of these proteins resulted in a significant decrease in overall ubiquitination, a process crucial for regulating inflammasome activation and autophagy. Consistently, inflammasome markers caspase 1 (CASP1) and apoptosis-associated speck-like protein containing a CARD (ASC), as well as autophagy markers microtubule-associated protein 1A/1B-light chain 3 (LC3B) and Ras-related protein Rab-11 (RAB11A), showed decreased expression in miR-215 mimic-transfected and infected IPEC-J2 cells. To further validate these findings, human intestinal epithelial cells (HT29) were used as a complementary model, providing additional insights into conserved immune pathways and extending the observations made in the porcine system. Overall, our findings demonstrate that miR-215 plays a significant role in modulating host inflammasome activation and autophagy by targeting proteins involved in ubiquitination during S. Typhimurium infection. Full article

Tea tree oil (TTO), acquired from Melaleuca alternifolia (Maiden & Betche) Cheel, Myrtaceae, is a widely utilized essential oil (EO) due to its bioactive properties. The identification and quantification of TTO ingredients is generally performed by GC-MS, which provides the most accurate results. However, in some instances, the cost and time of analysis may pose a challenge. Thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) offer a simpler, faster, cost-effective alternative capable of simultaneously analyzing and quantifying multiple samples. In addition, for more complex oils, two-dimensional (2D) or multigradient development (MGD) TLC provide better separation. Nevertheless, further development is sometimes necessary for the isolation of comigrating components. This study showcases a combined 2D-MGD TLC/HPTLC method for the successful separation of TTO components of interest. While human error, limited separation, and the partial evaporation of volatile components may still present a challenge during the process, considerable recovery of mono- and sesquiterpenes was achieved. This protocol also resulted in the successful isolation of target oxygenated monoterpenes (OMs) producing highly pure terpinen-4-ol (100%) and α-terpineol (≥94%), confirmed by GC-MS. The accurate enantiomeric distribution of these major OMs was verified by GC-FID through the use of a chiral cyclodextrin-based stationary phase. The observed positive enantiomer range (area percent) as well as (+)/(−) ratio for each terpinen-4-ol and α-terpineol were within acceptable ISO criteria. Full article

Pouteria sapota, or “mamey sapote”, is a tropical fruit tree native to Central America and Southern Mexico, producing sweet, nutrient and vitamin-rich fruit. Several insect pests are known to infest P. sapota, but none have been associated with plant growth alterations. Eriophyoid mites are well known to cause plant malformations, but mites that cause this type of damage to mamey sapote have not been reported. Trees with abnormal leaf growth, including stunted leaves, outward curling, leaf yellowing, and diminishing overall tree vigor, were found in multiple locations in Southern Florida and one location in Brazil. Numerous plant samples were examined for the presence of minute eriophyoid-like mites, and a new species was found. It was morphologically described, and DNA fragments of the mitochondrial gene cytochrome c oxidase subunit I (COI), the nuclear subunit D2 region in 28S rDNA, and the ITS nuclear regions were PCR-amplified and sequenced. Morphological and molecular descriptions of the new species, named E. pouteriae sp. nov., are provided to aid the identification and future detection of this mite. Even though several species within the genus Eriophyes have been reported on other Sapotaceae species, this is the first eriophyoid mite known to be associated with mamey sapote. Full article

Leaf senescence, the final stage of leaf development, is crucial for plant fitness as it enhances nutrient reutilization, supporting reproductive success and overall plant adaptation. Understanding its molecular and genetic regulation is essential to improve crop resilience and productivity, particularly in the face of global climate change. This review explores the significant contributions of natural genetic diversity to our understanding of leaf senescence, focusing on insights from model plants and major crops. We discuss the physiological and adaptive significance of senescence in plant development, environmental adaptation, and agricultural productivity. The review emphasizes the importance of natural genetic variation, including studies on natural accessions, landraces, cultivars, and artificial recombinant lines to unravel the genetic basis of senescence. Various approaches, from quantitative trait loci mapping to genome-wide association analysis and in planta functional analysis, have advanced our knowledge of senescence regulation. Current studies focusing on key regulatory genes and pathways underlying natural senescence, identified from natural or recombinant accession and cultivar populations, are highlighted. We also address the adaptive implications of abiotic and biotic stress factors triggering senescence and the genetic mechanisms underlying these responses. Finally, we discuss the challenges in translating these genetic insights into crop improvement. We propose future research directions, such as expanding studies on under-researched crops, investigating multiple stress combinations, and utilizing advanced technologies, including multiomics and gene editing, to harness natural genetic diversity for crop resilience. Full article

Rice bean is an underutilized legume crop cultivated in Asia, and it is a good source of protein, minerals, and essential fatty acids for human consumption. Moreover, the leaves left over after harvesting rice bean seeds contain various biological constituents beneficial to humans and animals. In our study, we performed a de-novo transcriptome assembly of rice bean, characterized the WRKY transcription factors, and studied their response to aluminum stress. A total of 46.6 million clean reads, with a GC value of 43%, were generated via transcriptome sequencing. De novo assembly of the clean reads resulted in 90,933 transcripts and 74,926 unigenes, with minimum and maximum lengths of 301 bp and 24,052 bp, and N50 values of 1801 bp and 1710 bp, respectively. A total of 27,095 and 28,378 unigenes were annotated and subjected to GO and KEGG analyses. Among the unigenes, 15,593, 20,770, and 15,385 unigenes were identified in the domains of biological process, molecular function, and cellular component, respectively. A total of 16,132 unigenes were assigned to 188 pathways, including metabolic pathways (5500) and secondary metabolite biosynthesis (2858). Transcription factor analysis revealed 4860 unigenes from 98 different transcription factor families. For WRKY, a total of 95 unigenes were identified. Further analysis revealed the diverse response of WRKY transcription factors to aluminum stress. Collectively, the results of this study boost genomic resources and provide a baseline for further research on the role of WRKY transcription factors in aluminum tolerance in rice bean. Full article

Zoysiagrass (Zoysia spp.) and its hybrids are known for their low maintenance requirements and are widely utilized as warm-season turfgrass, which offers considerable ecological, environmental, and economic benefits in various environments. Molecular genetic approaches, including the identification and genetic engineering of valuable gene resources, present a promising opportunity to enhance the quality and performance of zoysiagrass. This review surveys the recent molecular genetic discoveries in zoysiagrass species, with a focus on elucidating plant responses to various abiotic and biotic stresses. Furthermore, this review explores the notable advancements in gene function exploration to reduce the maintenance demands of zoysiagrass cultivation. In addition, we discuss the achievements and potential of contemporary molecular and genetic tools, such as omics approaches and gene editing technologies, in developing zoysiagrass cultivars with desirable traits. Overall, this comprehensive review highlights future strategies that may leverage current molecular insights to accelerate zoysiagrass improvement and further promote sustainable turf management practices. Full article