Physiology and Molecular Biology of Plants最新文献

Heat shock proteins (HSPs) are known to play a crucial role in the response of plants to environmental stress, particularly heat stress. Nevertheless, the function of HSPs in salt stress tolerance in plants, especially in barley, remains largely unexplored. Here, we aimed to investigate and compare the salt tolerance mechanisms between wild barley EC_S1 and cultivated barley RGT Planet through a comprehensive analysis of physiological parameters and transcriptomic profiles. Results demonstrated that the number of differentially expressed genes (DEGs) in EC_S1 was significantly higher than in RGT Planet, indicating that wild barley gene regulation is more adaptive to salt stress. KEGG enrichment analysis revealed that DEGs were mainly enriched in the processes of photosynthesis, plant hormone signal transduction, and reactive oxygen species metabolism. Furthermore, the application of weighted gene correlation network analysis (WGCNA) enabled the identification of a set of key genes, including small heat shock protein (sHSP), Calmodulin-like proteins (CML), and protein phosphatases 2C (PP2C). Subsequently, a novel sHSP gene, HvHSP16.9 encoding a protein of 16.9 kDa, was cloned from wild barley, and its role in plant response to salt stress was elucidated. In Arabidopsis, overexpression of HvHSP16.9 increased the salt tolerance. Meanwhile, barley stripe mosaic virus-induced gene silencing (BSMV-VIGS) of HvHSP16.9 significantly reduced the salt tolerance in wild barley. Overall, this study offers a new theoretical framework for comprehending the tolerance and adaptation mechanisms of wild barley under salt stress. It provides valuable insights into the salt tolerance function of HSP, and identifies new candidate genes for enhancing cultivated barley varieties.

The elucidation of the molecular basis underlying plant-pathogen interactions is imperative for the development of sustainable resistance strategies against pathogens. Plants employ a dual-layered immunological detection and response system wherein cell surface-localized Pattern Recognition Receptors (PRRs) and intracellular Nucleotide-Binding Leucine-Rich Repeat Receptors (NLRs) play pivotal roles in initiating downstream signalling cascades in response to pathogen-derived chemicals. Pattern-Triggered Immunity (PTI) is associated with PRRs and is activated by the recognition of conserved molecular structures, known as Pathogen-Associated Molecular Patterns. When PTI proves ineffective due to pathogenic effectors, Effector-Triggered Immunity (ETI) frequently confers resistance. In ETI, host plants utilize NLRs to detect pathogen effectors directly or indirectly, prompting a rapid and more robust defense response. Additionally epigenetic mechanisms are participating in plant immune memory. Recently developed technologies like CRISPR/Cas9 helps in exposing novel prospects in plant pathogen interactions. In this review we explore the fascinating crosstalk and cooperation between PRRs and NLRs. We discuss epigenomic processes and CRISPR/Cas9 regulating immune response in plants and recent findings that shed light on the coordination of these defense layers. Furthermore, we also have discussed the intricate interactions between the salicylic acid and jasmonic acid signalling pathways in plants, offering insights into potential synergistic interactions that would be harnessed for the development of novel and sustainable resistance strategies against diverse group of pathogens.

Fungi are one of the most diverse organisms found in our surroundings. The heterotrophic lifestyle of fungi and the ever-changing external environmental factors pose numerous challenges for their survival. Despite all adversities, fungi continuously develop new survival strategies to secure nutrition and space from their host. During host–pathogen interaction, filamentous phytopathogens in particular, effectively infect their hosts by maintaining polarised growth at the tips of hyphae. The fungal cell wall, being the prime component of host contact, plays a crucial role in fortifying the intracellular environment against the harsh external environment. Structurally, the fungal cell wall is a highly dynamic yet rigid component, responsible for maintaining cellular morphology. Filamentous pathogens actively maintain their dynamic cell wall to compensate rapid growth on the host. Additionally, they secrete effectors to dampen the sophisticated mechanisms of plant defense and initiate various downstream signaling cascades to repair the damage inflicted by the host. Thus, the fungal cell wall serves as a key modulator of fungal pathogenicity. The fungal cell wall with their associated signaling mechanisms emerge as intriguing targets for host immunity. This review comprehensively examines and summarizes the multifaceted findings of various research groups regarding the dynamics of the cell wall in filamentous fungal pathogens during host invasion.

Rice cultivation in Northeast India (NEI) primarily relies on rainfed conditions, making it susceptible to severe drought spells that promote the onset of brown spot disease (BSD) caused by Bipolaris oryzae. This study investigates the response of prevalent rice cultivars of NEI to the combined stress of drought and B. oryzae infection. Morphological, physiological, biochemical, and molecular changes were recorded post-stress imposition. Qualitative assessment of reactive oxygen species through DAB (3,3-diaminobenzidine) assay confirmed the elicitation of plant defense responses. Based on drought scoring system and biochemical analyses, the cultivars were categorized into susceptible (Shasharang and Bahadur), moderately susceptible (Gitesh and Ranjit), and moderately tolerant (Kapilee and Mahsuri) groups. Antioxidant enzyme accumulation (catalase, guaiacol peroxidase) and osmolyte (proline) levels increased in all stressed plants, with drought-tolerant cultivars exhibiting higher enzyme activities, indicating stress mitigation efforts. Nevertheless, electrolyte leakage and lipid peroxidation rates increased in all stressed conditions, though variations were observed among stress types. Based on findings from a previous transcriptomic study, a total of nine genes were chosen for quantitative real-time PCR analysis. Among these, OsEBP89 appeared as a potential negative regulatory gene, demonstrating substantial upregulation in the susceptible cultivars at both 48 and 72 h post-treatment (hpt). This finding suggests that OsEBP89 may play a role in conferring drought-induced susceptibility to BSD in the rice cultivars being investigated.

Faba bean (Vicia faba L.) is a winter season grain legume and a rich source of the anti-parkinson drug, L-3,4-dihydroxyphenylalanine (L-DOPA). The biosynthesis of L-DOPA in plants is not uniform and remains largely unexplored. While the hydroxylase activities of Tyrosine Hydroxylase (TH), the Cytochrome P450 (CYP450) class of enzymes, and Polyphenol Oxidases (PPOs) on tyrosine substrate have been reported in plants, only the roles of PPOs in L-DOPA biosynthesis have been recently established in velvet bean (Mucuna pruriens). To understand the differential accumulation of L-DOPA in different tissues of faba bean, profiling of L-Tyrosine, L-DOPA, Tyramine, and Dopamine in different tissues was performed. Differential accumulation of L-DOPA depended on tissue type and maturity. Furthermore, dopamine biosynthesis through L-DOPA from L-Tyr was confirmed in faba bean. The expression analysis of PPOs in leaf and flower tissues revealed the selective induction of only four (HePPO-2, HePPO-7, HePPO-8b, and HePPO-10) out of ten genes encoding different PPOs mined from the faba bean genome. Higher accumulation of L-DOPA in young leaves and flower buds than in mature leaves and flowers was accompanied by significantly higher expression of HePPO-10 and HePPO-7, respectively. The role of various transcription factors contributing to such metabolite dynamics was also predicted. Further exploration of this mechanism using a multi-omics approach can provide meaningful insight and pave the way for enhancing L-DOPA content in crops.

Leucojum aestivum L. is an Amaryllidaceae bulbous plant with two alkaloids that have remarkable medicinal potential: galanthamine and lycorine. Although the presence of galanthamine in L. aestivum has commercial value for the pharmaceutical industry and the effect of water stress (WS) applications on secondary metabolite enhancement is well established in a variety of plants, no studies have been carried out to reveal the effectiveness of WS on this beneficial medicinal plant. Objective of the study was to investigate the effects of eight different WS treatments [Control, waterlogging (WL) condition, and drought stress conditions (water deficiency generated by water deficit irrigation-WDI 25%, 50%, and 75%- and polyethylene glycol-PEG 6000 15%, 30%, and 45%-)] on growth parameters, alkaloid levels (galanthamine and lycorine), non-enzymatic antioxidant activities (total phenol-flavonoid content and free radical scavenging activity), and enzymatic antioxidant activities [superoxide dismutase (SOD) and catalase (CAT)] of L. aestivum in a pot experiment. Based on the findings, maximum increases in growth parameters were obtained with PEG-induced WS treatments. Moderate water deficiency (50% WDI) produced the highest levels of galanthamine and lycorine, total phenol-flavonoid content, and antioxidant capacity, along with moderately elevated CAT activity in the bulbs. All WS treatments resulted in increased CAT activity in the bulbs. It was observed that bulbs had higher SOD and CAT activities under WL conditions had lower fresh weights and were close to control in terms of alkaloid levels, total phenol-flavonoid content, and free radical scavenging activity. When all of the outcomes were taken into account, it can be concluded that moderate water-deficit stress (50% WDI) was regarded as the most effective treatment for increasing the pharmaceutical value of L. aestivum.

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Bletilla striata (Thunb.) Rchb.f., a medicinal plant in the Orchidaceae family, is mainly found in East Asia and has extensive pharmacological activities. Plant's volatile components are important active ingredients with a wide range of physiological activities, and B. striata has a special odor and unique volatile components. Yet it has received little attention, hindering a full understanding of its phytochemical components. Employing the ultrasonic-assisted extraction method, the volatile components of B. striata's fibrous root, bud, aerial part and tuber were extracted, resulting in yields of 0.06%, 0.64%, 3.38% and 4.47%, respectively. A total of 78 compounds were identified from their chemical profiles using gas chromatography-mass spectrometry (GC–MS), including 45 components with the main compounds of linoleic acid (content accounting for 31.23%), n-hexadecanoic acid (13.53%), and octadecanoic acid (9.5%) from the tuber, 34 components with the main compounds of eicosane, 2-methyl- (28.42%), linoelaidic acid (10.43%), linoleic acid (4.53%), and n-hexadecanoic acid (6.91%) from the fibrous root, 38 components with the main compounds of pentadeca-6,9-dien-1-ol (9.29%), n-hexadecanoic acid (11%), eicosane,2-methyl- (23.43%), and linoleic acid (23.53%) from the bud, and 27 components with the main compounds of linoelaidic acid (5.97%), n-hexadecanoic acid (15.99%), and linolenic acid ethyl ester (18.9%) from the aerial part. Additionally, the growth inhibition activity against colon cancer HCT116 cells was evaluated using sulforhodamine B (SRB) assay and the thiazolyl blue tetrazolium bromide (MTT) assay, and the accumulation of reactive oxygen species (ROS) was determined using dichloro-dihydro-fluorescein diacetate (DCFH-DA) staining and fluorescence intensity analysis. The volatile extracts exhibited significant growth inhibitory efficacy against HCT116 cells, with half-maximal inhibitory concentration (IC₅₀) values of 3.65, 2.32, 2.42 and 3.89 mg/mL in the SRB assay, and 3.55, 2.58, 3.12 and 4.80 mg/mL in the MTT assay for the root, bud, aerial part, and tuber, respectively. Notably, treatment with the aerial part extract caused morphological changes in the cells and significantly raised the intracellular ROS level. In summary, the chemical profiles of the volatile components of B. striata were revealed for the first time, demonstrating a certain tissue specificity. Additionally, it demonstrated for the first time that these volatile extracts possess potent anti-colon cancer activity, highlighting the importance of these volatile components in B. striata's medicinal properties.

Sweet cherry (Prunus avium L.) is one of the most economically important fruits in the world. However, severe fruit abscission has brought significant challenges to the cherry industry. To better understand the molecular regulation mechanisms underlying excessive fruit abscission in sweet cherry, the fruit abscission characteristics, the anatomical characteristics of the abscission zone (AZ), as well as a homeodomain-Leucine Zipper gene family member PavHB16 function were analyzed. The results showed that the sweet cherry exhibited two fruit abscission peak stages, with the “Brooks” cultivar demonstrating the highest fruit-dropping rate (97.14%). During these two fruit abscission peak stages, both the retention pedicel and the abscising pedicel formed AZs. but the AZ in the abscising pedicel was more pronounced. In addition, a transcription factor, PavHB16, was identified from sweet cherry. The evolutionary analysis showed that there was high homology between PavHB16 and AtHB12 in Arabidopsis. Moreover, the PavHB16 protein was localized in the nucleus. Overexpression of PavHB16 in Arabidopsis accelerated petal shedding. In the PavHB16-overexpressed lines, the AZ cells in the pedicel became smaller and denser, and the expression of genes involved in cell wall remodeling, such as cellulase 3 gene (AtCEL3), polygalacturonase 1 (AtPG1), and expandin 24(AtEXPA24) were upregulated. The results suggest that PavHB16 may promote the expression of genes related to cell wall remodeling, ultimately facilitating fruit abscission. In summary, this study cloned the sweet cherry PavHB16 gene and confirmed its function in regulating sweet cherry fruit abscission, which provided new data for further study on the fruit abscission mechanism.

Lodging, a phenomenon characterized by the bending or breaking of rice plants, poses substantial constraints on productivity, particularly during the harvesting phase in regions susceptible to strong winds. The rice strong culm trait is influenced by the intricate interplay of genetic, physiological, epigenetic, and environmental factors. Stem architecture, encompassing morphological and anatomical attributes, alongside the composition of both structural and non-structural carbohydrates, emerges as a critical determinant of lodging resistance. The adaptive response of the rice culm to various biotic and abiotic environmental factors further modulates the propensity for lodging. Advancements in next-generation sequencing technologies have expedited the genetic dissection of lodging resistance, enabling the identification of pertinent genes, quantitative trait loci, and novel alleles. Concurrently, contemporary breeding strategies, ranging from biparental approaches to more sophisticated methods such as multi-parent-based breeding, gene pyramiding, genomic selection, genome-wide association studies, and haplotype-based breeding, offer perspectives on the genetic underpinnings of culm strength. This review comprehensively delves into physiological attributes, culm histology, epigenetic determinants, and gene expression profiles associated with lodging resistance, with a specialized focus on leveraging next-generation sequencing for candidate gene discovery.

In our study on the effect of cadmium (Cd) toxicity (200 µM) on the growth of Sorghum bicolor (L.) Moench plants, cultivated with arbuscular mycorrhizal fungi (AMF) (Glomus intraradices) and/or under seaweed treatment (3% Ulva lactuca extract) (U. lactuca), we found that AMF increased the tolerance of sorghum to cadmium stress, either alone or in combination with the seaweed treatment. Morphological parameters were higher in these two culture conditions, with increased chlorophyll content. AMF reduced Cd accumulation in roots and inhibited its translocation to the aerial part, while seaweed treatment alone significantly increased Cd accumulation in leaves and roots without affecting plant growth compared to stressed witnesses. Treatment with AMF and/or U. lactuca attenuated oxidative stress, measured by activation of superoxide dismutase, and resulted in a significant decrease in malondialdehyde and superoxide ions (O₂⁻) in treated plants. Furthermore, it induced significant alterations in carbon and nitrogen metabolic pathways, with a significant increase in the activity of enzymes such as glutamine synthetase, glutamate synthase (GOGAT), glutamate dehydrogenase, phosphoenolpyruvate carboxylase, aspartate aminotransferase and isocitrate dehydrogenase in the leaves of each treated plant. These results confirm that AMF, U. lactuca algae extract and their combination can improve the biochemical parameters of sorghum under Cd stress, through modification of the antioxidant response on one hand, and improved nitrogen absorption and assimilation efficiency on the other.