Planta最新文献

Main conclusion: Partial male sterile mutant offers high hybrid recovery and seed set upon crossing. Partial sterility is recessive, monogenic and caused due to impairment of pollen function, which is supported by ddRAD sequencing. Finger millet, a nutri-cereal, has wider adaptability mainly grown as a rainfed crop in arid and semiarid tropics of Asia and Africa. Highly autogamous nature and small florets makes the hybridization tedious and hence the genetic improvement has been very slow. To address this, a novel partial male sterile mutant (ps1) was characterized extensively in line of its utility in hybridization breeding. An in vivo pollen study using fluorescence microscopy revealed the cause of partial male sterility in ps1 mutant as impairment of pollen germination and pollen tube growth on stigma. The mutant sets ~ 10% seeds upon bagging, 20% under open pollination and up to 49% in controlled crossing. Hybrid recovery (outcrossing) in 46 crosses with ps1 ranged from 28.6% to 81.2% with an average of 56.7% under controlled crossing. An extensive genetic study using 46 F₁, 46 F₂ and 1 F₃ population revealed monogenic and recessive nature of partial male sterility. To identify single nucleotide polymorphism (SNP) associated with partial male sterility, double-digested restriction site-associated DNA (ddRAD) sequencing of ps1 mutant and its wild type (GPU 28) was performed using Illumina Hi-Seq2000 and shortlisted 69 clusters were functionally annotated in UniProt database. The Cluster 53,954 has annotated MYB-like transcription factor (A0MLT6_ORYSJ) which plays vital role in pollen tube growth, which warrants further validation. Characterization of ps1 mutant in this study demonstrates simplified hybridization in finger millet. This would enable breeders to handle more crosses and frequent hybridization to achieve higher productivity.

Main conclusion: A comparative analysis of NaCl-stressed flax genotypes reveals that microRNA828a, microRNA399g, microRNA168a, catalase, shoot length, and shoot dry weight are the most influential salt stress-responsive variables irrespective of the lignan (secoisolariciresinol diglucoside) content declared for the genotypes. Lignans are powerful antioxidants and plant defence molecules whose roles in mitigating salt stress are rarely studied or understood, particularly in flax (Linum usitatissimum L.). Flax is a rich source of lignans. This study assessed the response to salt stress in two flax genotypes, Flanders and Astella. Astella has a higher content of the lignan secoisolariciresinol diglucoside (SDG) than Flanders. The 3-week-old flax plants were subjected to 100 mM NaCl salt stress for 1 week. Morphological analyses revealed that the growth of Flanders was more suppressed under stress, indicating resource-saving behaviour compared to Astella. Salt stress caused Astella to produce more reactive oxygen species (ROS) and incur more cell damage than Flanders. Flanders exhibited comparatively higher levels of antioxidants, osmoprotection machinery, and lignan-related microRNAs, suggesting its enhanced ROS scavenging and superior cellular protection capabilities than Astella. However, multivariate analysis could not provide evidence for the direct involvement of lignans in stress adaptation. Instead, it was hypothesised that microRNAs play a pleiotropic role in the adaptation to salinity. The results demonstrated Flanders' superiority to Astella in salt stress mitigation. The findings could be used to improve the salinity tolerance of flax and other crop plants in future research.

Main conclusion: This study investigates the capability of leaf reflectance measurements to identify stress responses under combined stress treatment. Crops are subjected to various environmental stresses, mostly occurring in combination. Research on combined stresses is important, but most studies focus on single stresses. We analyzed physiological responses of two Capsicum species to single cold and salt stresses, which differ from the responses to combinations of these stresses. Combined stress caused growth to decrease more than individual stresses. Single cold stress significantly reduced photosynthetic pigments in both species. However, single salt stress increased pigments in C. annuum. Under combined stress, photosynthetic pigments were decreased to a lower extent compared to single cold stress. An increase in leaf reflectance around 550 nm and a significant shift in the red-edge peak of the first derivative corresponded with chlorophyll content. The effects of single cold and combined stress were similar, differing only in magnitude. Only C. chinense showed a response in leaf reflectance to salt stress. Spectral vegetation indices distinguished single cold from single salt stress, whereas the effects of single cold and the combined stress were similar, indicating a dominating effect of cold stress. The photochemical reflectance index (PRI), however, distinguished between all three treatments. This research confirms that the responses to combined stresses are unique and different from responses to individual stresses. A strong effect of one stress can mask another. This can lead to misinterpretation when combined stresses occur. The use of hyperspectral signals for quantification of responses to combined stresses must be carefully evaluated and established for further research to assist breeding of climate-resilient crops performing well under multi-stress events.

Main conclusion: The chloroplast genomes of Satureja are highly conserved but contain hypervariable loci like ndhF and ycf1. These loci provide powerful molecular tools for precise species identification, phylogenetic resolution, and future conservation efforts in this important genus. The genus Satureja (Lamiaceae) comprises a valuable number of aromatic herbs and shrubs with significant ecological, medicinal, and economic value, particularly in the Mediterranean and Southwest Asia. Satureja species are renowned for their therapeutic essential oils, yet their chloroplast (cp) genomic resources remain vastly understudied, with only S. montana complete cp genome available. To address this gap, we sequenced and analyzed the complete cp genomes of three taxonomically and ecologically distinct Satureja species (S. hortensis, S. khuzestanica, and S. montana subsp. variegata) and a new individual of S. montana, using Illumina sequencing and comparative genomic approaches. The assembled cp genomes exhibited a conserved quadripartite structure, with sizes ranging narrowly from 151,777 to 151,924 bp, featuring typical large (LSC) and small (SSC) single-copy regions flanked by inverted repeats (IRs). Genome annotation revealed 128-130 genes, including core photosynthetic and ribosomal genes, with notable interspecific variation in tRNA copy numbers. Comparative analyses identified hypervariable loci (ndhF, ycf1, petN) as promising DNA barcodes for species discrimination, while codon use bias strongly favored A/T-ending codons. Simple sequence repeats (SSRs) were predominantly mononucleotide (A/T), and long repetitive sequences showed species-specific length polymorphisms. Phylogenetic reconstruction using the whole cp genomes strongly supported the monophyly of Satureja and resolved infrageneric relationships with high bootstrap confidence (> 90%), placing these species in a distinct clade sister to Thymus and Mentha. Our study provides the first comprehensive cp genomic resource for Satureja, elucidating evolutionary patterns, identifying molecular markers for taxonomy, and establishing a foundation for future conservation and biotechnological applications in this economically important genus.

Main conclusion: Multifactorial stress combination negatively affects citrus performance, especially when these plants are under three or more stresses, affecting citrus growth at different levels including phenotypic, physiological, biochemical and molecular levels. In nature, biotic and abiotic factors affect plant growth and development. "Multifactorial Stress Combination" (MFSC) refers to situations in which three or more stressors occur simultaneously or sequentially on plants. Its importance lies in the drastic reduction in plant survival under such complex stress scenarios. In this work, we studied the effect of five stresses and their combinations (deficiencies in nitrogen, phosphorus and potassium with water and heat stress) on Carrizo citrange, a citrus genotype widely used in physiological studies. Nutrient deficiencies were applied for three months using specific irrigation solutions. To impose heat stress, plants were maintained for three days in environmental chambers set at 24 °C (control) and 40 °C (heat), while drought was simulated by transferring them to dry perlite. MFSC clearly impacted plant phenotype, increasing leaf damage and decreasing shoot weight, particularly under three or more stressors. Gas exchange parameters and total pigment content were only affected under the combination of four or five stressors, respectively. Oxidative damage increased in plants subjected to five stresses, as indicated by increased malonaldehyde content. A progressive rise was observed in abscisic acid, jasmonic acid, salicylic acid, phaseic acid and indole-3-acetic acid as stress complexity increased, highlighting their involvement as key regulators of the plant stress response. The observed upregulation of galactose metabolism suggested an alternative pathway for energy production and sugar accumulation as essential responses to a complex stress scenario. Overall, results demonstrate the severe impact of MFSC on citrus development, with plant damage increasing exponentially under three or more stressors.

Main conclusion: Germination is a developmental stage in which plants accumulate higher levels of bioactive metabolites. However, this potential remains largely unexplored in medicinal herbs and therapeutic applications. Sprouting represents a brief yet metabolically dynamic phase in plant development, during which dormant seeds initiate enzymatic activation and begin synthesizing a range of bioactive compounds. Compared to dry seeds or mature plants, sprouts often contain higher levels of phenolics, flavonoids, vitamins, and other secondary metabolites, enhancing their nutritional and pharmacological value. While edible sprouts from food crops have been extensively studied, sprouts derived from medicinal plants remain largely overlooked. This is surprising given their natural richness in pharmacologically relevant phytochemicals. This perspective draws primarily on original experimental studies that investigated phytochemical and physiological changes during sprouting of medicinal plants. These studies were identified through searches in scientific databases using keywords related to medicinal plants, sprouts, and bioactive compounds. We summarize existing studies on species such as Trigonella foenum-graecum, Nigella sativa, Silybum marianum, Arctium lappa, Trifolium pratense, and Glycyrrhiza uralensis, and identify other promising candidates with high germination potential but uncharacterized phytochemical profiles at the sprout stage. Environmental variables, such as light quality, seed priming, or nutrient supplementation, can further modulate phytochemical composition during germination. We also discuss practical limitations, including low biomass yield, microbial safety concerns, and lack of standardized protocols. Overall, sprouts offer a responsive, scalable, and experimentally tractable model for exploring and optimizing phytochemical expression in medicinal plants. We propose that this early developmental window offers overlooked opportunities for phytopharmacology, functional foods, and natural product discovery.

Main conclusion: Expression of the APX gene and ROS levels in four Gossypium species are interrelated, functioning in cotton pigment gland development and abiotic stress responses. Ascorbate peroxidases (APXs) represent a crucial family of antioxidant enzymes that play essential roles in plant responses to environmental stresses and the regulation of developmental processes. Pigment glands in cotton are specialized structures formed through programmed cell death (PCD), a process inherently linked to the accumulation of reactive oxygen species (ROS). Despite the well-established functions of APXs in maintaining ROS homeostasis and the recognized involvement of ROS in pigment gland development, the specific interactions between APXs and ROS within these glands remain largely uncharacterized. In this study, bioinformatics approaches were employed to systematically analyze APX genes across multiple cotton varieties. Expression profiling revealed that APX genes exhibited both upregulated and downregulated responses to environmental stresses as well as hydrogen peroxide (H₂O₂) treatment, suggesting a potential dual-function mechanism for APXs in regulating ROS levels. Significant accumulation of ROS was observed in glands, while negligible levels were detected in glandless cotton. Comparative analysis indicated that most APX genes displayed higher expression levels in glanded cotton plants. Functional validation experiments demonstrated that overexpression and knockdown of GhMYC2-like-a key regulator involved in pigment gland formation-respectively induced and repressed the expression of six APX genes. These findings suggest that members of the APX family are integral components within the regulatory network governing cotton pigment gland formation. This study not only provides novel insights into the role of APXs within cotton biology but also establishes a solid foundation for future investigations into their functions related to ROS-mediated processes.

Main conclusion: Apiaceae morphological dormancy and germination differ between crop and wild species, and among crop cultivars in the mechanical, hormonal and thermal mechanisms that control pericarp (fruit coat) weakening and pre-gremination embryo growth. The Apiaceae disperse morphologically (MD) or morphophysiologically dormant mericarps, indehicent fruits in which the single seed is encased by the pericarp (fruit coat) and the underdeveloped (small) embryo is embedded in abundant living endosperm tissue. Pre-germination embryo growth from an initial to a critical relative embryo size (embryo:fruit or embryo:seed length ratio) is a requirement for the completion of germination by radicle emergence. The roles and mechanisms of pre-gremination embryo growth and pericarp constraint were investigated by embryo-growth imaging, pericarp ablation/biomechanics, tissue-specific hormone analytics, and population-based thermal-time threshold modelling. Comparison of Apiaceae crop cultivars, including Pastinaca sativa (parsnip), Apium graveolens (celery) and Daucus carota (carrot) with > 50 wild Apiaceae species revealed that the initial relative embryo sizes of crop species are significantly larger compared to wild species. Interestingly, the critical relative embryo sizes of the phylogenetic group that contains parsnip, were smaller for the crop compared to wild species. ABA-insensitive and auxin-promoted pre-germination embryo growth was blocked by heat (thermoinhibition), while the completion of germination by radicle emergence was inhibited by ABA. The thick pericarp of parsnip decreased in thickness and mechanical tissue resistance in parallel with the pre-germination embryo growth, while the thin pericarps of celery and carrot did not change. Parsnip pericarp contained significantly higher contents of the germination-inhibiting hormones abscisic acid (ABA) and cis-(+)-12-oxo-phytodienoic acid (cis-OPDA) compared to celery pericarp. Pericarp ablation experiments revealed that it acts as a mechanical and chemical (ABA, cis-OPDA) constraint (coat component of MD), and has a key role in narrowing the permissive temperature window for germination.