Role In Defense Responses Research Articles

Sequence-based analysis of the rice CAMTA family: haplotype and network analyses

The calmodulin-binding transcription activator (CAMTA) family contributes to stress responses in many plant species. The Oryza sativa ssp. japonica genome harbors seven CAMTA genes; however, intraspecific variation and functional roles of this gene family have not been determined. Here, we comprehensively evaluated the structure and characteristics of the CAMTA genes in japonica rice using bioinformatics approaches and RT-qPCR. Within the CAMTA gene and promoter sequences, 527 single nucleotide polymorphisms were retrieved from 3,024 rice accessions. The CAMTA genes could be subdivided into 5–14 haplotypes. Association analyses between haplotypes and phenotypic traits, such as grain weight and salt stress parameters, identified phenotypic differences between rice subpopulations harboring different CAMTA haplotypes. Co-expression analyses and the identification of CAMTA-specific binding motifs revealed candidate genes regulated by CAMTA. A Gene Ontology functional enrichment analysis of 690 co-expressed genes revealed that CAMTA genes have key roles in defense responses. An interaction analysis identified 30 putative CAMTA interactors. Three genes were identified in co-expression and interaction network analyses, suggesting that they are potentially regulated by CAMTAs. Based on all information obtained together with the phenotypes of the CRISPR-Cas9 knockout mutant lines of three OskCAMTA genes generated, CAMTA1 likely plays important roles in the response to salt stress in rice. Overall, our findings suggest that the CAMTA gene family is involved in development and the salt stress response and reveal candidate target genes, providing a basis for further functional characterization.

Comparison on stress memory of two Hypnaceae moss species to haze

Abstract Industrialization and the rapid growth of economies have caused severe environmental pollution, which might impact the survival of sensitive species. In this study, we investigated the defense responses of two common mosses with varying anti-haze capacities, Hypnum callichroum and Homomallium incurvatum, in response to simulated haze pollution. Photoprotection and antioxidant mechanisms of both mosses were measured immediately after the first exposure to the haze treatment, followed by the initial recovery stage and again after exposure to secondary stress and secondary recovery. Haze exposure caused severe oxidative stress and photodamage in both H. callichroum and H. incurvatum. Metabolic processes such as photorespiration, the ascorbate–glutathione cycle, and secondary metabolism—which play roles in defense responses—were significantly activated in both moss species after haze treatment. During the recovery following haze stress, H. callichroum exhibited a significant stress memory response, as evidenced by the greater accumulation of several memory substances, including xanthophylls and phenolic acids. However, H. incurvatum did not exhibit a strong stress memory response, which might explain its relatively inferior anti-haze capacity in the natural environment.

Pathogenesis-Related 1 (PR1) Protein Family Genes Involved in Sugarcane Responses to Ustilago scitaminea Stress.

Plant resistance against biotic stressors is significantly influenced by pathogenesis-related 1 (PR1) proteins. This study examines the systematic identification and characterization of PR1 family genes in sugarcane (Saccharum spontaneum Np-X) and the transcript expression of selected genes in two sugarcane cultivars (ROC22 and Zhongtang3) in response to Ustilago scitaminea pathogen infection. A total of 18 SsnpPR1 genes were identified at the whole-genome level and further categorized into four groups. Notably, tandem and segmental duplication occurrences were detected in one and five SsnpPR1 gene pairs, respectively. The SsnpPR1 genes exhibited diverse physio-chemical attributes and variations in introns/exons and conserved motifs. Notably, four SsnpPR1 (SsnpPR1.02/05/09/19) proteins displayed a strong protein-protein interaction network. The transcript expression of three SsnpPR1 (SsnpPR1.04/06/09) genes was upregulated by 1.2-2.6 folds in the resistant cultivar (Zhongtang3) but downregulated in the susceptible cultivar (ROC22) across different time points as compared to the control in response to pathogen infection. Additionally, SsnpPR1.11 was specifically upregulated by 1.2-3.5 folds at 24-72 h post inoculation (hpi) in ROC22, suggesting that this gene may play an important negative regulatory role in defense responses to pathogen infection. The genetic improvement of sugarcane can be facilitated by our results, which also establish the basis for additional functional characterization of SsnpPR1 genes in response to pathogenic stress.

Terpene synthases GhTPS6 and GhTPS47 participate in resistance to Verticillium dahliae in upland cotton

Terpene synthases (TPSs) are enzymes responsible for catalyzing the production of diverse terpenes, the largest class of secondary metabolites in plants. Here, we identified 107 TPS gene loci encompassing 92 full-length TPS genes in upland cotton (Gossypium hirsutum L.). Phylogenetic analysis showed they were divided into six subfamilies. Segmental duplication and tandem duplication events contributed greatly to the expansion of TPS gene family, particularly the TPS-a and TPS-b subfamilies. Expression profile analysis screened out that GhTPSs may mediate the interaction between cotton and Verticillium dahliae. Three-dimensional structures and subcellular localizations of the two selected GhTPSs, GhTPS6 and GhTPS47, which belong to the TPS-a subfamily, demonstrated similarity in protein structures and nucleus and cytoplasm localization. Virus-induced gene silencing (VIGS) of the two GhTPSs yielded plants characterized by increased wilting and chlorosis, more severe vascular browning, and higher disease index than control plants. Additionally, knockdown of GhTPS6 and GhTPS47 led to the down-regulation of cotton terpene synthesis following V. dahliae infection, indicating that these two genes may positively regulate resistance to V. dahliae through the modulation of disease-resistant terpene biosynthesis. Overall, our study represents a comprehensive analysis of the G. hirsutum TPS gene family, revealing their potential roles in defense responses against Verticillium wilt.

The functional and structural characterisation of the bZIP transcription factors from Myristica fragrans Houtt. associated to plant disease-resistant defence: An insight from transcriptomics and computational modelling

The bZIP transcription factors play crucial roles in various aspects of plant biology, including development, defence mechanisms, senescence, and responses to both biotic and abiotic environmental stresses. Myristica fragrans Houtt. transcriptome analysis has identified 15 bZIP transcription factors, each exhibiting major conserved domains and motifs such as BRLZ, MFMR, and DOG1. Functional characterisation of these identified MfbZIP factors indicates their predominant localisation within the nucleus. Phylogenetic analysis reveals that MfbZIP factors cluster into three subgroups alongside annotated bZIP sequences from Magnolia sinica and Arabidopsis thaliana. Moreover, gene ontology (GO) analysis highlights several key functions of MfbZIP, including involvement in defence responses, abscisic acid-induced signalling pathways, and DNA-binding transcription factor activity. Further investigation through KEGG pathway analysis reveals that the amino acid sequences of MfbZIP contain binding motifs for proteins such as TGA, implicated in plant hormone signal transduction pathways associated with disease resistance. To confirm the disease-defence-related activity of the TGA binding protein within MfbZIP, we employed amino acid sequences for 3-D ab initio modelling. Subsequently, we analysed TGA-NPR1 interactions using docking and molecular dynamics simulation analysis. These analyses shed light on the functional and structural aspects of TGA, demonstrating its stable association with NPR1 protein and its significance in the expression of PR1 protein, thus playing a pivotal role in defence responses against pathogens.

De novo assembly-based transcriptome analysis of resistant and susceptible potato varieties to Phytophthora infestans

AbstractAn effective tool for discovering differentially expressed genes (DEGs) related to late blight (LB) resistance is the transcriptome sequencing of potatoes. The aim of this study was to compare transcriptome expression analysis in incompatible and compatible interactions via high-throughput sequencing. Furthermore, we performed a bioinformatics analysis to screen a large number of specific transcription factors (TFs) and DEGs linked to Phytophthora infestans infection. Two locally cultivated potato varieties were chosen from evaluation assays conducted in two consecutive seasons and based on the disease severity (DS) values. These varieties were the highly resistant Jelly (HR) to P. infestans and the moderately susceptible Annabelle (MS). Ribonucleic acid-sequencing (RNA-seq) was achieved for the two varieties with their controls through the BGISEQ-500 sequencing platform. The RNA-seq analysis identified P. infestans-responsive genes and their expression in potatoes. The mechanism of the response of these cultivars to the P. infestans pathogen by TFs and DEG genes, which play an important role in defense response, was investigated. The Gene Ontology (GO) analysis classified 46,248 unigenes in the HR and 26,921 unigenes in MS into the following three categories: biological process, cellular component, and molecular functions. More genes were responsible for the cellular component category, biological process, and molecular functions in HR compared to MS. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the significantly enriched DEGs were included in the plant–pathogen interaction, biosynthesis of secondary metabolites, and ribosome. In addition, 1874 transcription factor genes belonging to 85 families were indicated in the DEGs, of which MYB and AP2-EREBP genes were the most abundant. Besides, multiple genes related to LB resistance showed differential expression during infection. It also sheds light on the molecular mechanisms behind potato resistance to P. infestans infection.

Silencing GmWRKY33B genes leads to reduced disease resistance in soybean

The WRKYs are a group of plant-specific transcription factors that play important roles in defense responses. In this study, we silenced 2 GmWRKY33B homologous genes using a bean pod mosaic virus (BPMV) vector carrying a single fragment from the conserved region of the GmWRKY33B genes. Silencing GmWRKY33B did not result in morphological changes. However, significantly reduced resistances to Pseudomonas syringae pv. glycinea (Psg) and soybean mosaic virus (SMV) were observed in the GmWRKY33B-silenced plants, indicating a positive role of the GmWRKY33B genes in disease resistance. Kinase assay showed that silencing the GmWRKY33B genes significantly reduced the activation of GmMPK6, but not GmMPK3, in response to flg22 treatment. Reverse transcriptase PCR (RT-PCR) analysis of the genes encoding prenyltransferases (PTs), which are the key enzymes in the biosynthesis of glyceollin, showed that the Psg-induced expression of these genes was significantly reduced in the GmWRKY33B-silenced plants compared with the BPMV-0 empty vector plants, which correlated with the presence of the W-boxes in the promoter regions of these genes. Taken together, our results suggest that GmWRKY33Bs are involved in soybean immunity through regulating the activation of the kinase activity of GmMPK6 as well as through regulating the expression of the key genes encoding the biosynthesis of glyceollins.

Sugarcane transcription factor ScWRKY4 negatively regulates resistance to pathogen infection through the JA signaling pathway

WRKY transcription factors, transcriptional regulators unique to plants, play an important role in defense response to pathogen infection. However, the resistance mechanisms of WRKY genes in sugarcane remain unclear. In the present study, gene ontology (GO) enrichment analysis revealed that WRKY gene family in sugarcane was extensively involved in the response to biotic stress and in defense response. We identified gene ScWRKY4, a class IIc member of the WRKY gene family, in sugarcane cultivar ROC22. This gene was induced by salicylic acid (SA) and methyl jasmonate (MeJA) stress. Interestingly, expression of ScWRKY4 was down-regulated in smut-resistant sugarcane cultivars but up-regulated in smut-susceptible sugarcane cultivars infected with Sporisorium scitamineum. Moreover, stable overexpression of the ScWRKY4 gene in Nicotiana benthamiana enhanced susceptibility to Fusarium solani var. coeruleum and caused down-regulated expression of immune marker-related genes. Transcriptome analysis indicated suppressed expression of most JAZ genes in the signal transduction pathway. ScWRKY4 interacted with ScJAZ13 to repress its expression. We thus hypothesized that the ScWRKY4 gene was involved in the regulatory network of plant disease resistance, most likely through the JA signaling pathway. The present study depicting the molecular involvement of ScWRKY4 in sugarcane disease resistance lays a foundation for future investigation.

Genome-Wide Identification and Expression Analysis of Chitinase Genes in Watermelon under Abiotic Stimuli and Fusarium oxysporum Infection.

Chitinases, which catalyze the hydrolysis of chitin, the primary components of fungal cell walls, play key roles in defense responses, symbiotic associations, plant growth, and stress tolerance. In this study, 23 chitinase genes were identified in watermelon (Citrullus lanatus [Thunb.]) and classified into five classes through homology search and phylogenetic analysis. The genes with similar exon-intron structures and conserved domains were clustered into the same class. The putative cis-elements involved in the responses to phytohormone, stress, and plant development were identified in their promoter regions. A tissue-specific expression analysis showed that the ClChi genes were primarily expressed in the roots (52.17%), leaves (26.09%), and flowers (34.78%). Moreover, qRT-PCR results indicate that ClChis play multifaceted roles in the interaction between plant/environment. More ClChi members were induced by Race 2 of Fusarium oxysporum f. sp. niveum, and eight genes were expressed at higher levels on the seventh day after inoculation with Races 1 and 2, suggesting that these genes play a key role in the resistance of watermelon to Fusarium wilt. Collectively, these results improve knowledge of the chitinase gene family in watermelon species and help to elucidate the roles played by chitinases in the responses of watermelon to various stresses.

Genetic analyses and prediction for lodging‑related traits in a diverse Iranian hexaploid wheat collection

Lodging is one of the most important limiting environmental factors for achieving the maximum yield and quality of grains in cereals, including wheat. However, little is known about the genetic foundation underlying lodging resistance (LR) in wheat. In this study, 208 landraces and 90 cultivars were phenotyped in two cropping seasons (2018–2019 and 2019–2020) for 19 LR-related traits. A genome-wide association study (GWAS) and genomics prediction were carried out to dissect the genomic regions of LR. The number of significant marker pairs (MPs) was highest for genome B in both landraces (427,017) and cultivars (37,359). The strongest linkage disequilibrium (LD) between marker pairs was found on chromosome 4A (0.318). For stem lodging-related traits, 465, 497, and 478 marker-trait associations (MTAs) and 45 candidate genes were identified in year 1, year 2, and pooled. Gene ontology exhibited genomic region on Chr. 2B, 6B, and 7B control lodging. Most of these genes have key roles in defense response, calcium ion transmembrane transport, carbohydrate metabolic process, nitrogen compound metabolic process, and some genes harbor unknown functions that, all together may respond to lodging as a complex network. The module associated with starch and sucrose biosynthesis was highlighted. Regarding genomic prediction, the GBLUP model performed better than BRR and RRBLUP. This suggests that GBLUP would be a good tool for wheat genome selection. As a result of these findings, it has been possible to identify pivotal QTLs and genes that could be used to improve stem lodging resistance in Triticum aestivum L.

RD29A and RD29B rearrange genetic and epigenetic markers in priming systemic defense responses against drought and salinity

Drought has become the most important limiting factor to crop productions. Research thus far has been devoted to identifying drought-responsive genes (DRGs) via breeding and engineering approaches. Still, these efforts have not resulted in a solution to combat drought’s effects because the ectopic expression of most DRGs causes adverse effects that reduce plant growth and yields. Lately, we discovered that two DRGs, Response to Desiccation (RD)29A and RD29B, induced by Paenibacillus polymyxa CR1, a plant growth-promoting rhizobacterium capable of priming drought tolerance and concurrently stimulating plant growth, play pivotal roles in defense responses against drought. In this study, we employ the ChlP and qRT-PCR analyses and further clarify that P. polymyxa CR1 reformats the chromatin/transcriptional memory of RD29s, positioned as upstream controllers that fine-tune the temporal dynamic of stress-regulating transcription factors (TFs) in elaborating induced systemic drought tolerance without growth penalties. Two genes coordinate the upregulation of NAC TFs, while feedback inhibiting CBF TFs, which regulate downstream DRG expressions. This supports that RD29s are unique, feasible transgene candidates for improving plants’ survival capacity in both optimal and drought conditions. However, the mode of action of RD29A and RD29B are partly independent, exerting distinct roles in disparate ecological states. When subjected to increasing NaCl concentrations, the KO mutant of RD29A (rd29a) displayed enhanced tolerance compared to WT and rd29b plants, proposing that RD29B, but not RD29A, a key player in conferring WT-like tolerance to salinity stress; further studies will be needed to optimize/maximize their applications in engineering for-profit drought and/or broad-spectrum stress tolerant crops.

Tea plant (Camellia sinensis) lipid metabolism pathway modulated by tea field microbe (Colletotrichum camelliae) to promote disease.

Tea is one of the most popular healthy and non-alcoholic beverages worldwide. Tea anthracnose is a disease in tea mature leaves and ultimately affects yield and quality. Colletotrichum camelliae is a dominant fungal pathogen in the tea field that infects tea plants in China. The pathogenic factors of fungus and the susceptible factors in the tea plant are not known. In this work, we performed molecular and genetic studies to observe a cerato-platanin protein CcCp1 from C. camelliae, which played a key role in fungal pathogenicity. △CcCp1 mutants lost fungal virulence and reduced the ability to produce conidia. Transcriptome and metabolome were then performed and analysed in tea-susceptible and tea-resistant cultivars, Longjing 43 and Zhongcha 108, upon C. camelliae wild-type CCA and △CcCp1 infection, respectively. The differentially expressed genes and the differentially accumulated metabolites in tea plants were clearly overrepresented such as linolenic acid and linoleic acid metabolism, glycerophospholipid metabolism, phenylalanine biosynthesis and metabolism, biosynthesis of flavonoid, flavone and flavonol etc. In particular, the accumulation of jasmonic acid was significantly increased in the susceptible cultivar Longjing 43 upon CCA infection, in the fungal CcCp1 protein dependent manner, suggesting the compound involved in regulating fungal infection. In addition, other metabolites in the glycerophospholipid and phenylalanine pathway were observed in the resistant cultivar Zhongcha 108 upon fungal treatment, suggesting their potential role in defense response. Taken together, this work indicated C. camelliae CcCp1 affected the tea plant lipid metabolism pathway to promote disease while the lost function of CcCp1 mutants altered the fungal virulence and plant response.

The role of photorespiration in plant immunity.

To defend themselves in the face of biotic stresses, plants employ a sophisticated immune system that requires the coordination of other biological and metabolic pathways. Photorespiration, a byproduct pathway of oxygenic photosynthesis that spans multiple cellular compartments and links primary metabolisms, plays important roles in defense responses. Hydrogen peroxide, whose homeostasis is strongly impacted by photorespiration, is a crucial signaling molecule in plant immunity. Photorespiratory metabolites, interaction between photorespiration and defense hormone biosynthesis, and other mechanisms, are also implicated. An improved understanding of the relationship between plant immunity and photorespiration may provide a much-needed knowledge basis for crop engineering to maximize photosynthesis without negative tradeoffs in plant immunity, especially because the photorespiratory pathway has become a major target for genetic engineering with the goal to increase photosynthetic efficiency.

The metabolites involved in phenylpropanoid biosynthesis increase the susceptibility of octoploid strawberry to crown rot caused by Colletotrichum siamense

Crown rot caused by Colletotrichum siamense is a serious disease affecting strawberry that leads to large-scale losses, both in their quality and yield, in the Yangtze River Basin, China. Secondary metabolites are known to play pivotal roles in defense responses against invading pathogens, and identifying metabolites involved in crown rot is necessary for understanding induced resistance and developing improved genetic resistance against strawberry crown rot. To explore this research topic, the infection process was verified via observation of the phenotypes and histopathology of susceptible ‘Benihoppe’ strawberry inoculated with C. siamense. Following this, metabolomic analysis was used that identified phenolic acids, flavonoids, and amino acids as the metabolites accumulated in the rotten crown caused by the C. siamense infection process. Furthermore, the transcripts encoding enzymes involved in the ‘phenylpropanoid biosynthesis’ of phenolic acids, trans-cinnamate 4-monooxygenase, caffeoylshikimate esterase, and caffeic acid 3-O-methyltransferase were all upregulated in the rotten crown, as shown by transcriptomic analysis and qRT-PCR. In addition, the metabolites p-coumaric acid, caffeic acid, and ferulic acid in the ‘phenylpropanoid biosynthesis’ pathway all enhanced C. siamense infection, as shown by an exogenous validation experiment. Together, the results demonstrate that the ‘phenylpropanoid biosynthesis’ pathway was induced during crown rot and thus highlight the potentially crucial regulatory role of this pathway in plant immunity.

A Chromosome-level Reference Genome of African Oil Palm Provides Insights into Its Divergence and Stress Adaptation

The palm family (Arecaceae), consisting of ∼ 2600 species, is the third most economically important family of plants. The African oil palm (Elaeis guineensis) is one of the most important palms. However, the genome sequences of palms that are currently available are still limited and fragmented. Here, we report a high-quality chromosome-level reference genome of an oil palm, Dura, assembled by integrating long reads with ∼ 150× genome coverage. The assembled genome was 1.7 Gb in size, covering 94.5% of the estimated genome, of which 91.6% was assigned into 16 pseudochromosomes and 73.7% was repetitive sequences. Relying on the conserved synteny with oil palm, the existing draft genome sequences of both date palm and coconut were further assembled into chromosomal level. Transposon burst, particularly long terminal repeat retrotransposons, following the last whole-genome duplication, likely explains the genome size variation across palms. Sequence analysis of the VIRESCENS gene in palms suggests that DNA variations in this gene are related to fruit colors. Recent duplications of highly tandemly repeated pathogenesis-related proteins from the same tandem arrays play an important role in defense responses to Ganoderma. Whole-genome resequencing of both ancestral African and introduced oil palms in Southeast Asia reveals that genes under putative selection are notably associated with stress responses, suggesting adaptation to stresses in the new habitat. The genomic resources and insights gained in this study could be exploited for accelerating genetic improvement and understanding the evolution of palms.

Comprehensive Genome-Wide Analysis and Expression Pattern Profiling of PLATZ Gene Family Members in Solanum Lycopersicum L. under Multiple Abiotic Stresses.

PLATZ (plant AT-rich sequence and zinc-binding) family proteins with two conserved zinc-dependent DNA-binding motifs are transcription factors specific to the plant kingdom. The functions of PLATZ proteins in growth, development, and adaptation to multiple abiotic stresses have been investigated in various plant species, but their role in tomato has not been explored yet. In the present work, 20 non-redundant Solanum lycopersicum PLATZ (SlPLATZ) genes with three segmentally duplicated gene pairs and four tandemly duplicated gene pairs were identified on eight tomato chromosomes. The comparative modeling and gene ontology (GO) annotations of tomato PLATZ proteins indicated their probable roles in defense response, transcriptional regulation, and protein metabolic processes as well as their binding affinity for various ligands, including nucleic acids, peptides, and zinc. SlPLATZ10 and SlPLATZ17 were only expressed in 1 cm fruits and flowers, respectively, indicating their preferential involvement in the development of these organs. The expression of SlPLATZ1, SlPLATZ12, and SlPLATZ19 was up- or down-regulated following exposure to various abiotic stresses, whereas that of SlPLATZ11 was induced under temperature stresses (i.e., cold and heat stress), revealing their probable function in the abiotic stress tolerance of tomato. Weighted gene co-expression network analysis corroborated the aforementioned findings by spotlighting the co-expression of several stress-associated genes with SlPLATZ genes. Confocal fluorescence microscopy revealed the localization of SlPLATZ−GFP fusion proteins in the nucleus, hinting at their functions as transcription factors. These findings provide a foundation for a better understanding of the structure and function of PLATZ genes and should assist in the selection of potential candidate genes involved in the development and abiotic stress adaptation in tomato.

Genome-wide analysis of terpene synthase gene family to explore candidate genes related to disease resistance in Prunus persica.

In plants, a family of terpene synthases (TPSs) is responsible for the biosynthesis of terpenes and contributes to species-specific diversity of volatile organic compounds, which play essential roles in fitness of plants. However, little is known about the TPS gene family in peach and/or nectarine (Prunus persica L.). In this study, we identified 40 PpTPS genes in peach genome v2.0. Although these PpTPSs could be clustered into five classes, they distribute in several gene clusters of three chromosomes, share conserved exon-intron organizations, and code similar protein motifs. Thirty-five PpTPSs, especially PpTPS2, PpTPS23, PpTPS17, PpTPS18, and PpTPS19, altered their transcript levels after inoculation with Botryosphaeria dothidea, a cause of peach gummosis, compared to the mock treatments, which might further affect the contents of 133 terpenoids at 48 hours and/or 84 hours post inoculations in the current-year shoots of 'Huyou018', a highly susceptible nectarine cultivar. Moreover, about fifteen PpTPSs, such as PpTPS1, PpTPS2, PpTPS3, and PpTPS5, showed distinct expression patterns during fruit development and ripening in two peach cultivars, yellow-fleshed 'Jinchun' and white-fleshed 'Hikawa Hakuho'. Among them, the transcription level of chloroplast-localized PpTPS3 was obviously related to the content of linalool in fruit pulps. In addition, elevated concentrations (0.1 g/L to 1.0 g/L) of linalool showed antifungal activities in PDA medium. These results improve our understanding of peach PpTPS genes and their potential roles in defense responses against pathogens.

Comparative Appraisal of Leaf Proteomic and Mass Spectrometry Analyses During FusariumWilt Infection in Resistance and Susceptible Genotypes of Castor (Ricinus communis L.).

The resistant and susceptible genotypes of castor were utilized for leaf proteomic study during Fusarium wilt infection. The histopathological study was observed under SEM and it confirmed that the infection of Fusarium oxysporum f. sp. ricini was higher in the root of susceptible JI-35, while incompatible interaction is observed in resistant SKI-215 genotype. The acidic and neutral proteins were maximally up-expressed with 2 to 171 kDa in treated resistant and 2 to 150 kDa in treated susceptible interactions. In resistant genotype, the leaf proteins were recognized with 3.0- and 5.8-fold higher at infection stage and post-infection stage, respectively, as compared to susceptible genotype. The highly up expressions of leaf acidic (4.76 pI) and basic (8.77 pI) proteins were found with 224.94- and 61.68-fold change, respectively during the post-infection stage in treated resistance compared to its control. The protein spots at 4.76 pI and 8.77 pI were characterized with nanoLC-MS Triple TOF and were recognized as signalling molecules small GTP binding protein (23 kDa) and actin (8 kDa), respectively, on the basis of mass spectrometry and peptide sequences. However, basic and neutral proteins were up regulated as 30.11- and 20.30-fold changes in treated susceptible compared to its control. These proteins were identified as HSP90 (10 kDa) and LEA (27 kDa) proteins. The 148 kDa protein is recognized as histidine kinase in incompatible resistant interaction compared to compatible susceptible (serine threonine protein kinase, 65 kDa) as common acidic protein at 3.80 pI during infection stage. Some acidic proteins were maximally up-regulated in the leaf of resistant castor genotype and played a significant role in defense response.

Genome-wide characterization of cys-tathionine-β-synthase domain-containing proteins in sugarcane reveals their role in defense responses under multiple stressors.

Cys-tathionine-β-synthase (CBS) domain-containing proteins (CDCPs) are essential for regulating plant responses to various biotic and abiotic stressors. This study describes the systematic identification and characterization of CDCP family genes in Saccharum spontaneum. A total of 95 SsCDCP genes and eight phylogenetic groups were identified that were distributed over 29 chromosomes of the AP85-441 genome. Most (78/95) SsCDCPs underwent fragment duplication events, and 64 gene pairs were located in synteny blocks. Expression profiling of nine ShCDCPs was also carried out in the Saccharum spp. cultivars ROC22 and MT11-611 that are resistant and susceptible to red stripe, respectively, in response to: (i) Infection by the bacterial pathogen Acidovorax avenue subsp. avenae (Aaa); (ii) abiotic stressors (drought and salinity); and (iii) exogenous salicylic acid (SA) treatment. Members of one gene pair (ShCBSD-PB1-5A and ShCBSD-PB1-7A-1) with a fragment duplication event acted as negative regulators in sugarcane under four stresses, as supported by the significantly decreased expression levels of ShCBSD-PB1-5A (23–83%) and ShCBSD-PB1-7A-1 (15–75%) at all-time points, suggesting that they have functional redundancy. Genes in another pair, ShCBS-4C and ShCBS-4D-1, which have a fragment duplication event, play opposing regulatory roles in sugarcane exposed to multiple stresses, particularly Aaa and NaCl treatments. ShCBS-4C expression was significantly decreased by 32–77%, but ShCBS-4D-1 expression was dramatically upregulated by 1.2–6.2-fold in response to Aaa treatment of both cultivars across all-time points. This result suggested that both genes exhibited functional divergence. Meanwhile, the expression of SsCBSDCBS-5A was significantly upregulated in ROC22 by 1.4–4.6-fold in response to the four stressors. These findings provide important clues for further elucidating the function of ShCDCP genes in sugarcane responding to a diverse range of stresses.

Genome-wide identification of Cymbidium sinense WRKY gene family and the importance of its Group III members in response to abiotic stress.

Transcription factors (TFs) of the WRKY family play pivotal roles in defense responses and secondary metabolism of plants. Although WRKY TFs are well documented in numerous plant species, no study has performed a genome-wide investigation of the WRKY gene family in Cymbidium sinense. In the present work, we found 64 C. sinense WRKY (CsWRKY) TFs, and they were further divided into eight subgroups. Chromosomal distribution of CsWRKYs revealed that the majority of these genes were localized on 16 chromosomes, especially on Chromosome 2. Syntenic analysis implied that 13 (20.31%) genes were derived from segmental duplication events, and 17 orthologous gene pairs were identified between Arabidopsis thaliana WRKY (AtWRKY) and CsWRKY genes. Moreover, 55 of the 64 CsWRKYs were detectable in different plant tissues in response to exposure to plant hormones. Among them, Group III members were strongly induced in response to various hormone treatments, indicating their potential essential roles in hormone signaling. We subsequently analyzed the function of CsWRKY18 in Group III. The CsWRKY18 was localized in the nucleus. The constitutive expression of CsWRKY18 in Arabidopsis led to enhanced sensitivity to ABA-mediated seed germination and root growth and elevated plant tolerance to abiotic stress within the ABA-dependent pathway. Overall, our study represented the first genome-wide characterization and functional analysis of WRKY TFs in C. sinense, which could provide useful clues about the evolution and functional description of CsWRKY genes.