Upregulation of the glycine-rich protein-encoding gene GhGRPL enhances plant tolerance to abiotic and biotic stressors by promoting secondary cell wall development

Abiotic and biotic stressors adversely affect plant survival,biomass generation,and crop yields.As the global availability of arable land declines and the impacts of global warming intensify,such stressors may have increasingly pronounced effects on agricultural productivity.Currently,researchers face the overarching challenge of comprehensively enhancing plant resilience to abiotic and biotic stressors.The secondary cell wall plays a crucial role in bolstering the stress resistance of plants.To increase plant resistance to stress through genetic manipulation of the secondary cell wall,we cloned a cell wall protein designated glycine-rich protein-like(GhGRPL)from cotton fibers,and found that it is specifically expressed during the period of secondary cell wall biosynthesis.Notably,this protein differs from its Arabidopsis homolog,AtGRP,since its glycine-rich domain is deficient in glycine residues.GhGRPL is involved in secondary cell wall deposition.Upregulation of GhGRPL enhances lignin accumulation and,consequently,the thickness of the secondary cell walls,thereby increasing the plant’s resistance to abiotic stressors,such as drought and salinity,and biotic threats,including Verticillium dahliae infection.Conversely,interference with GhGRPL expression in cotton reduces lignin accumulation and compromises that resistance.Taken together,our findings elucidate the role of GhGRPL in regulating secondary cell wall development through its influence on lignin deposition,which,in turn,reinforces cell wall robustness and impermeability.These findings highlight the promising near-future prospect of adopting GhGRPL as a viable,effective approach for enhancing plant resilience to abiotic and biotic stress factors.

Dual function of Arabidopsis A TAF1 in abiotic and biotic stress responses

NAC family genes encode plant-specific transcription factors involved in diverse biological processes. In this study, the Arabidopsis NAC gene ATAF1 was found to be induced by drought, high-salinity, abscisic acid （ABA）, methyl jasmonate, mechanical wounding, and Botrytis cinerea infection. Significant induction of ATAF1 was found in an ABA-deficient mutant aba2 subjected to drought or high salinity, revealing an ABA-independent mechanism of expression. Arabidopsis ATAFl-overexpression lines displayed many altered phenotypes, including dwarfism and short primary roots. Furthermore, in vivo experiments indicate that ATAF1 is a bonafide regulator modulating plant responses to many abiotic stresses and necrotrophic-pathogen infection. Overexpression of ATAF1 in Arabidopsis increased plant sensitivity to ABA, salt, and oxidative stresses. Especially, ATAF1 overexpression plants, but not mutant lines, showed remarkably enhanced plant tolerance to drought. Additionally, ATAF1 overexpression enhanced plant susceptibility to the necrotrophic pathogen B. cinerea, but did not alter disease symptoms caused by avirulent or virulent strains of P. syringae pv tomato DC3000. Transgenic plants overexpressing ATAF1 were hypersensitive to oxidative stress, suggesting that reactive oxygen intermediates may be related to ATAFl-mediated signaling in response to both pathogen and abiotic stresses.

Isolation and Expression Patterns of Rice WRKY82 Transcription Factor Gene Responsive to Both Biotic and Abiotic Stresses

WRKY transcription factors are involved in the regulation of response to biotic and abiotic stresses in plants. A full-length cDNA clone of rice WRKY82 gene （OsWRKY82） was isolated from a cDNA library generated from leaves infected by Magnaporthe grisea. OsWRKY82 contained an entire open reading frame in length of 1 701 bp, and was predicted to encode a polypeptide of 566 amino acid residues consisting of two WRKY domains, each with a zinc finger motif of C2H2, belonging to the WRKY subgroup I. OsWRKY82 shared high identity at the amino acid level with those from Sorghum bicolor, Hordeum vulgare, and Zea mays. The transcript level of OsWRKY82 was relatively higher in stems, leaves, and flowers, and less abundant in grains. It was induced by inoculation with M. grisea and Rhizoctonia solani. However, the inducible expression in incompatible rice-M. grisea interactions was earlier and greater than that in compatible interactions. The expression of OsWRKY82 was up-regulated by methyl jasmonate and ethephon, whereas salicylic acid exerted no effects on its expression. Moreover, OsWRKY82 exhibited transcriptional activation ability in yeast. Additionally, OsWRKY82 transcripts could be induced by wounding and heat shocking, but not by abscisic acid, cold, high salinity and dehydration. By contrast, gibberellin suppressed the expression of OsWRKY82. These indicate that OsWRKY82 is a multiply stress-inducible gene responding to both biotic and abiotic stresses, and may be involved in the regulation of defense response to pathogens and tolerance against abiotic stresses by jasmonic acid/ethylene-dependent signaling pathway.

Role of Pathogen-Related Protein 10 (PR 10) under Abiotic and Biotic Stresses in Plants

Members of the Pathogenesis Related(PR)10 protein family have been identified in a variety of plant species and a wide range of functions ranging from defense to growth and development has been attributed to them.PR10 protein possesses ribonuclease(RNase)activity,interacts with phytohormones,involved in hormone-mediated signalling,afforded protection against various phytopathogenic fungi,bacteria,and viruses particularly in response to biotic and abiotic stresses.The resistance mechanism of PR10 protein may include activation of defense signalling pathways through possible interacting proteins involved in mediating responses to pathogens,degradation of RNA of the invading pathogens.Moreover,several morphological changes have been shown to accompany the enhanced abiotic stress tolerance.In this review,the possible mechanism of action of PR10 protein against biotic and abiotic stress has been discussed.Furthermore,our findings also confirmed that the in vivo Nitric oxide(NO)is essential for most of environmental abiotic stresses and disease resistance against pathogen infection.The proper level of NO may be necessary and beneficial,not only in plant response to the environmental abiotic stress,but also to biotic stress.The updated information on this interesting group of proteins will be useful in future research to develop multiple stress tolerance in plants.

Genome-Wide Analysis of von Willebrand Factor A Gene Family in Rice for Its Role in Imparting Biotic Stress Resistance with Emphasis on Rice Blast Disease

von Willebrand factor A(vWA)genes are well characterized in humans except for few BONZAI genes,but the vWA genes are least explored in plants.Considering the novelty and vital role of vWA genes,this study aimed at characterization of vWA superfamily in rice.Rice genome was found to have 40 vWA genes distributed across all the 12 chromosomes,and 20 of the 40 vWA genes were unique while the remaining shared large fragment similarities with each other,indicating gene duplication.In addition to vWA domain,vWA proteins possess other different motifs or domains,such as ubiquitin interacting motif in protein degradation pathway,and RING finger in protein-protein interaction.Expression analysis of vWA genes in available expression data suggested that they probably function in biotic and abiotic stress responses including hormonal response and signaling.The frequency of transposon elements in the entire 3K rice germplasm was negligible except for 9 vWA genes,indicating the importance of these genes in rice.Structural and functional diversities showed that the vWA genes in a blast-resistant rice variety Tetep had huge variations compared to blast-susceptible rice varieties HP2216 and Nipponbare.qRT-PCR analysis of vWA genes in Magnaporthe oryzae infected rice tissues indicated OsvWA9,OsvWA36,OsvWA37 and OsvWA18 as the optimal candidate genes for disease resistance.This is the first attempt to characterize vWA gene family in plant species.

Mechanism of tobacco osmotin gene in plant responses to biotic and abiotic stress tolerance:A brief history

Plants are recurrently exposed to myriads of biotic and abiotic stresses leading to several biochemical and physiological variations that cause severe impacts on plant growth and survival.To overcome these challenges,plants activate two primary defense mechanisms,such as structural response(cell wall strengthening and waxy epidermal cuticle development)and metabolic changes,including the synthesis of anti-microbial compounds and proteins,especially the pathogenesis-related(PR)proteins.PR proteins are members of a super large family of defense proteins that exhibit antimicrobial activities.Their over-expression in plants provides tolerance to many abiotic and biotic stresses.PR proteins have been classified into 17 families,including PR-5–also called thaumatin-like proteins(TLPs)that involve osmotin and osmotin-like proteins(OLPs).Osmotin was first identified in tobacco(Nicotiana tabacum var.Wisconsin 38),and then its homolog proteins(OLPs)were reported from the whole plant kingdom.Osmotin and OLPs are ubiquitous in all fruits and vegetables.Their expression has been detected in various plant tissues and organs.The phylogenetic tree studies revealed that the osmotin group originated from spermatophytes.Moreover,the atomic structure of OLP has shown similarity to thaumatin and TLPs from monocot and eudicot species,which determines a strong evolutionary pressure in flowering plants for conserving thaumatin fold.This is associated with the role of these proteins against pathogens as defense molecules and to induce stress tolerance to plants against several biotic and abiotic factors.In this review,we have briefly described the development history of osmotin,including its function and mechanism to induce biotic and abiotic stress tolerance to plants.

Molecular Analysis of Rice CIPKs Involved in Both Biotic and Abiotic Stress Responses

Plant calcineurin B-like （CBL） proteins have been proposed as important Ca2＋ sensors and specifically interact with CBL-interacting protein kinases （CIPKs） in plant-specific calcium signaling. Here, we identified and isolated 15 CIPK genes in a japonica rice variety Nipponbare based on the predicted sequences of rice CIPK gene family. Gene structure analysis showed that these 15 genes were divided into intron-less and intron-rich groups, and OsCIPK3 and OsCIPK24 exhibited alternative splicing in their mature process. The phylogenetic analyses indicated that rice CIPKs shared an ancestor with Arabidopsis and poplar CIPKs. Analyses of gene expression showed that these OsCIPK genes were differentially induced by biotic stresses such as bacterial blight and abiotic stresses （heavy metal such as Hg2＋, high salinity, cold and ABA）. Interestingly, five OsCIPK genes, OsCIPK1, 2, 10, 11 and 12, were transcriptionally up-regulated after bacterial blight infection whereas four OsCIPK genes, OsCIPK2, 10, 11 and 14, were induced by all treatments, indicating that some of OsCIPK genes are involved in multiple stress response pathways in plants. Our finding suggests that CIPKs play a key role in both biotic and abiotic stress responses.

Research Progress of miRNAs in Rice(Oryza sativa L.)under Biotic and Abiotic Stresses

Stresses are defined as a variety of environmental factors that pose adverse impacts on plant growth and survival. Rice is an important food crop, whose quality and yield may be affected by environmental stresses. MicroRNAs play an important role in response to stresses, which regulate gene expression at the post-transcription level by cleaving target mRNAs and inhibiting mRNA translation. This paper summarized the mechanism of action of miRNAs and introduced research progress of miRNAs in rice under biotic and abiotic stresses, which provided reference for revealing the functional role of rice miRNAs in stress resistance.

Versatile Potentiality of Silicon in Mitigation of Biotic and Abiotic Stresses in Plants: A Review

The “quasi-essential element” silicon (Si) is not considered indispensable for plant growth and its accumulation varies between species largely due to differential uptake phenomena. Silicon uptake and distribution is a complex process involving the participation of three transporters (Lsi1, Lsi2 and Lsi6) and is beneficial during recovery from multiple stresses. This review focuses on the pivotal role of silicon in counteracting several biotic and abiotic stresses including nutrient imbalances, physical stresses together with uptake, transport of this metalloid in a wide variety of dicot and monocot species. The knowledge on the beneficial effects of silicon and possible Si-induced mechanisms of minimizing stress has been discussed. Accumulation of silicon beneath the cuticles fortifies the cell wall against pathogen attack. Si-induced reduction of heavy metal uptake, root-shoot translocation, chelation, complexation, upregulation of antioxidative defense responses and regulation of gene expression are the mechanisms involved in alleviation of heavy metal toxicity in plants. Silicon further improves growth and physiological attributes under salt and drought stress. Effective use of silicon in agronomy can be an alternative to the prevalent practice of traditional fertilizers for maintaining sustainable productivity. Therefore, soil nutrition with fertilizers containing plant-available silicon may be considered a cost-effective way to shield plant from various stresses, improve plant growth as well as yield and attain sustainable cultivation worldwide.

Biotic Stress Induced Biochemical and Isozyme Variations in Ginger and Tomato by <i>Ralstonia solanacearum</i>

This unique study evaluates the effects of Ralstonia solanacearum (Rs) induced biotic stress in two cultivars, Zingiber officinale (ginger) and Lycopersicon esculentum (tomato). They were grown in pots and hydroponic systems with controls;to induce biotic stress, about 8 × 104 colony forming units of Rs suspension was injected into the healthy test plants. Upon induction of Rs stress, highly significant (p 0.01) biochemical changes (%) were noticed in respect to controls: carbohydrate content was generally high in both plants;while they showed decreased starch and protein contents;phenolics showed a swing of decrease or increase between pot and hydroponic systems;and all plants in general showed higher (3-6 fold) proline content upon induction of biotic stress. Regarding oxidative stress isozymes (OSE), superoxide dismutase (EC 1.15.1.1) isozymes were normally 3, but treated hydroponics had 4 with comparable relative mobility values;peroxidase (EC 1.11.1.7) isozymes were generally 2, except for treated hydroponic tomato. Briefly, Rs induced biotic stress caused wilt symptoms in ginger, but did not affect tomato though its biochemical and OSE patterns especially in those grown as hydroponics were elicited to significantly higher levels.

Systemic analysis of metabolome reconfiguration in Arabidopsis after abiotic stressors uncovers metabolites that modulate defense against pathogens

Understanding plant immune responses is complex because of the high interdependence among biological processes in homeostatic networks.Hence,the integration of environmental cues causes network rewiring that interferes with defense responses.Similarly,plants retain molecular signatures configured under abiotic stress periods to rapidly respond to recurrent stress,and these can alter immunity.Metabolome changes imposed by abiotic stressors are persistent,although their impact on defense remains to be clar-ified.In this study,we profiled metabolomes of Arabidopsis plants under several abiotic stress treatments applied individually or simultaneously to capture temporal trajectories in metabolite composition during adverse conditions and recovery.Further systemic analysis was performed to address the relevance of me-tabolome changes and extract central features to be tested in planta.Our results demonstrate irreversibility in major fractions of metabolome changes as a general pattern in response to abiotic stress periods.Func-tionalanalysisofmetabolomesandco-abundancenetworkspoints toconvergence inthereconfigurationof organic acid and secondary metabolite metabolism.Arabidopsis mutant lines for components related to these metabolic pathways showed altered defense capacities against different pathogens.Collectively,our data suggest that sustained metabolome changes configured in adverse environments can act as mod-ulators of immune responses and provide evidence for a new layer of regulation in plant defense.

Field evaluation of durum wheat landraces for prevailing abiotic and biotic stresses in highland rainfed regions of Iran

Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat(Triticum turgidum L. var. durum) entries originating in several countries along with four check varieties were evaluated for biotic stresses:yellow rust(Puccinia striiformis Westendorf f. sp. tritici) and wheat stem sawfly(WSS) Cephus cinctus Norton(Hymenoptera: Cephidae), and abiotic stresses: cold and drought. The main objectives were to(i) quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and(ii) characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were observed.Landraces resistant to each stress were identified and agronomically characterized.Percentage reduction due to the stresses varied from 11.4%(yellow rust) to 21.6%(cold stress) for 1000-kernel weight(TKW) and from 19.9(yellow rust) to 91.9%(cold stress) for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.

Untangling the biotic stress in the late Maastrichtian Deccan-benchmark interval of Bidart(France)

The late Maastrichtian witnessed substantial surges in Deccan volcanism,prompting the hypothesis that these voluminous pulses may have instigated repeated episodes of ocean acidification during this period.The Cretaceous-Palaeogene(K/Pg)boundary at Bidart(France)is preceded by a~0.5 m thick interval with geochemical and taphonomic vestiges of an ocean acidification event linked with Deccan volcanism.New planktic foraminifera census and morphometric data now confirm biotic stress conditions related to acidification in the Deccan benchmark interval.The absolute abundance data of larger(>150μm)heavily calcified planktic morphogroups show fluctuating populations throughout zone CF1(spanning the final~225 ky),lowest peaks within the Deccan benchmark,and a demographic collapse(>90%)at the K/Pg boundary.The analyzed species are generally reduced in size,with thinner test walls in this~0.5 m interval,indicating the likelihood of calcification stress as a contributor to the overall biotic stress.At the K/Pg boundary,maximum biotic stress is recorded in all the tested faunal proxies.A preliminary graphic correlation of zone CF1 at Bidart with the auxiliary GSSP at Elles(Tunisia)constrains the Deccan benchmark interval of high biotic stress to the final~58ky of the late Maastrichtian,culminating in the K/Pg mass extinction.The volcanogenic Hg peaks coincident with faunal and taphonomic evidence of ocean acidification strengthen the Deccan-related ocean acidification hypothesis.

Abiotic and Biotic Factors Controlling Grain Aroma along Value Chain of Fragrant Rice:A Review

The aroma of fragrant rice is one of the grain quality attributes that significantly influenceconsumer preferences and prices in world markets. The volatile compound 2-acetyl-1-pyrroline (2AP) isrecognized as a key component of the aroma in fragrant rice. The variation in grain 2AP content amongvarious fragrant rice varieties is associated with the expression of the badh2 gene, with 19 alleles havingbeen identified so far. The grain 2AP content is strongly influenced by environmental and managementfactors during cultivation as well as post-harvest conditions. This review pinpointed the major abiotic andbiotic factors that control grain 2AP content. Abiotic factors refer to water, temperature, light quality,fertilizer application (both macro- and micro-nutrients), and soil properties, including salinity, while bioticfactors include microorganisms that produce aromatic compounds, thus influencing the grain aroma infragrant rice. Post-harvest management, including storage and drying conditions, can significantly impactthe grain 2AP content, and proper post-harvest conditions can intensify the grain aroma. This reviewsuggests that there are rice varieties that can serve as potential sources of genetic material for breedingrice varieties with high grain aroma content. It offers an overview of recent research on the major factorsaffecting the aroma content in fragrant rice. This knowledge will facilitate further research on theproduction of high-quality rice to meet the demands of farmers and consumers.

Hydrogen sulfide regulates abiotic stress tolerance and biotic stress resistance in Arabidopsis

Hydrogen sulfide （H2S） is an important gaseous molecule in various plant developmental processes and plant stress responses. In this study, the transgenic Arabidopsis thaliana plants with modulated expressions of two cysteine desulfhydrases, and exogenous H2S donor （sodium hydrosulfide, NariS） and H2S scavenger （hypotaurine, HT） pre-treated plants were used to dissect the involvement of H2S in plant stress responses. The cysteine desulfhydrases overexpressing plants and NariS pre-treated plants exhibited higher endogenous H2S level and improved abiotic stress tolerance and biotic stress resistance, while cysteine desulfhydrases knockdown plants and HT pre-treated plants displayed lower endogenous H2S level and decreased stress resistance. Moreover, H2S upregulated the transcripts of multiple abiotic and biotic stress-related genes, and inhibited reactive oxygen species （ROS） accumulation. Interest- ingly, MlR393-mediated auxin signaling including MIR393a/b and their target genes （TIR1, AFB1, AFB2, and AFB3） was transcrip-tionally regulated by H2S, and was related with H2S-induced antibacterial resistance. Moreover, H2S regulated 50 carbon metabolites including amino acids, organic acids, sugars, sugar alcohols, and aromatic amines. Taken together, these results indicated that cysteine desulfhydrase and H2S conferred abiotic stress tolerance and biotic stress resistance, via affecting the stress-related gene expressions, ROS metabolism, metabolic homeostasis, and MIR393-targeted auxin receptors.

VIGE:virus-induced genome editing for improving abiotic and biotic stress traits in plants

Agricultural production is hampered by disease,pests,and environmental stresses.To minimize yield loss,it is important to develop crop cultivars with resistance or tolerance to their respective biotic and abiotic constraints.Transformation techniques are not optimized for many species and desirable cultivars may not be amenable to genetic transformation,necessitating inferior cultivar usage and time-consuming introgression through backcrossing to the preferred variety.Overcoming these limitations will greatly facilitate the development of disease,insect,and abiotic stress tolerant crops.One such avenue for rapid crop improvement is the development of viral systems to deliver CRISPR/Cas-based genome editing technology to plants to generate targeted beneficial mutations.Viral delivery of genomic editing constructs can theoretically be applied to span the entire host range of the virus utilized,circumventing the challenges associated with traditional transformation and breeding techniques.Here we explore the types of viruses that have been optimized for CRISPR/Cas9 delivery,the phenotypic outcomes achieved in recent studies,and discuss the future potential of this rapidly advancing technology.

Regulation of plant responses to biotic and abiotic stress by receptor-like cytoplasmic kinases

As sessile organisms,plants have to cope with environmental change and numerous biotic and abiotic stress.Upon perceiving environmental cues and stress signals using different types of receptors,plant cells initiate immediate and complicated signaling to regulate cellular processes and respond to stress.Receptor-like cytoplasmic kinases(RLCKs)transduce signals from receptors to cellular components and play roles in diverse biological processes.Recent studies have revealed the hubbing roles of RLCKs in plant responses to biotic stress.Emerging evidence indicates the important regulatory roles of RLCKs in plant responses to abiotic stress,growth,and development.As a pivot of cellular signaling,the activity and stability of RLCKs are dynamically and tightly controlled.Here,we summarize the current understanding of how RLCKs regulate plant responses to biotic and abiotic stress.

Abiotic and Biotic Stresses and Changes in the Lignin Content and Composition in Plants

Lignin is a polymer of phenylpropanoid compounds formed through a complex biosynthesis route, represented by a metabolic grid for which most of the genes involved have been sequenced in several plants, mainly in the model-plants Arabidopsis thaliana and Populus. Plants are exposed to different stresses, which may change lignin content and composition. In many cases, particularly for plant-microbe interactions, this has been suggested as defence responses of plants to the stress. Thus, understanding how a stressor modulates expression of the genes related with lignin biosynthesis may allow us to develop study-models to increase our knowledge on the metabolic control of lignin deposition in the cell wall. This review focuses on recent literature reporting on the main types of abiotic and biotic stresses that alter the biosynthesis of lignin in plants.

Interplay between hydrogen sulfide and other signaling molecules in the regulation of guard cell signaling and abiotic/biotic stress response

Stomatal aperture controls the balance between transpirational water loss and photosynthetic carbon dioxide(CO2)uptake.Stomata are surrounded by pairs of guard cells that sense and transduce environmental or stress signals to induce diverse endogenous responses for adaptation to environmental changes.In a recent decade,hydrogen sulfide(H2S)has been recognized as a signaling molecule that regulates stomatal movement.In this review,we summarize recent progress in research on the regulatory role of H2S in stomatal movement,including the dynamic regulation of phytohormones,ion homeostasis,and cell structural components.We focus especially on the cross talk among H2S,nitric oxide(NO),and hydrogen peroxide(H2O2)in guard cells,as well as on H2S-mediated post-translational protein modification(cysteine thiol persulfidation).Finally,we summarize the mechanisms by which H2S interacts with other signaling molecules in plants under abiotic or biotic stress.Based on evidence and clues from existing research,we propose some issues that need to be addressed in the future.

A comparative analysis of paddy crop biotic stress classification using pre-trained deep neural networks

The agriculture sector is no exception to the widespread usage of deep learning tools and techniques.In this paper,an automated detection method on the basis of pre-trained Convolutional Neural Network(CNN)models is proposed to identify and classify paddy crop biotic stresses from the field images.The proposed work also provides the empirical comparison among the leading CNN models with transfer learning from the ImageNet weights namely,Inception-V3,VGG-16,ResNet-50,DenseNet-121 and MobileNet-28.Brown spot,hispa,and leaf blast,three of the most common and destructive paddy crop biotic stresses that occur during the flowering and ripening growth stages are considered for the experimentation.The experimental results reveal that the ResNet-50 model achieves the highest average paddy crop stress classification accuracy of 92.61%outperforming the other considered CNN models.The study explores the feasibility of CNN models for the paddy crop stress identification as well as the applicability of automated methods to non-experts.