Susceptible Varieties Research Articles

ANTIBIOSIS AND ANTIXENOSIS IN TOMATO GENOTYPES AGAINST Helicoverpa armigera HUBNER

<p><strong>Background</strong>. Farmers rely on the use of synthetic insecticides in managing <em>Helicoverpa</em> <em>armigera</em>, hole-boring insect pest on tomato, but they are detrimental to human health. Therefore a more reliable and ecofriendly control measure is needed such as host plant resistance<strong>. Objective</strong>. To assess the mechanisms of resistance in tomato varieties: NGB00724, NGB00724, Anaya, Kelvin, Mona, Roma VF (susceptible varieties), Tropimech and UC82B in laboratory and screen house. <strong>Methodology</strong>. Second larval instars were fed with leaves of the different tomato varieties and their development was observed till adult stage. Study was done in the screen house where number of larvae and eggs were also observed. Larval period and weight, and percentage adult emergence were assessed in tomato varieties. Metabolites (phenol, flavonoids, terpenoids, protein, reducing sugars and total sugars) in tomato leaves were determined following standard procedures. <strong>Results</strong>. <em>Helicoverpa</em> <em>armigera</em> fed with tomato leaves, Anaya recorded the lowest larval period (9.67 days). Also, larvae fed on Anaya and Mona had the lowest larval weight (0.19 g and 0.25 g). Also significantly lower percentage of adult emergence was observed on Anaya and Mona (16.7%) Mona, NGB00725 and Anaya significantly harbored the lower number of <em>Helicoverpa</em> <em>armigera</em> adult (0.1, 0.4, 0.4). The lowest number of eggs (0.5) was recorded from adults placed on Anaya variety. There was high and negative significant correlation of r = -0.865 between phenols and adult emergence. Phenols and oviposition were significantly negatively correlated (r = -0.816). <strong>Implication. </strong>Anaya and Mona hinder the development of <em>Helicoverpa</em> <em>armigera</em> larvae when fed on it. Phenol has negative impact on the development and oviposition of <em>Helicoverpa</em> <em>armigera</em>. <strong>Conclusion</strong>. It was revealed through this study that availability of promising resistant varieties can effectively combat the damage caused by <em>Helicoverpa</em> <em>armigera</em> and lessen the shortcomings related with the application of conventional chemical insecticides in tomato production.</p>

Combining transcriptome and metabolome analysis to understand the response of sorghum to Melanaphis sacchari

BackgroundThe sorghum aphid Melanaphis sacchari (Zehntner) (Homoptera: Aphididae) is an important insect in the late growth phase of sorghum (Sorghum bicolor L.). However, the mechanisms of sorghum response to aphid infestation are unclear.ResultsIn this paper, the mechanisms of aphid resistance in different types of sorghum varieties were revealed by studying the epidermal cell structure and performing a transcriptome and metabolome association analysis of aphid-resistant and aphid-susceptible varieties. The epidermal cell results showed that the resistance of sorghum to aphids was positively correlated with epidermal cell regularity and negatively correlated with the intercellular space and leaf thickness. Transcriptome and metabolomic analyses showed that differentially expressed genes in the resistant variety HN16 and susceptible variety BTX623 were mainly enriched in the flavonoid biosynthesis pathway and differentially expressed metabolites were mainly related to isoflavonoid biosynthesis and flavonoid biosynthesis. The q-PCR results of key genes were consistent with the transcriptome expression results. Meanwhile, the metabolome test results showed that after aphidinfestation, naringenin and genistein were significantly upregulated in the aphid-resistant variety HN16 and aphid-susceptible variety BTX623 while luteolin was only significantly upregulated in BTX623. These results show that naringenin, genistein, and luteolin play important roles in plant resistance to aphid infestation. The results of exogenous spraying tests showed that a 1‰ concentration of naringenin and genistein is optimal for improving sorghum resistance to aphid feeding.ConclusionsIn summary, the physical properties of the sorghum leaf structure related to aphid resistance were studied to provide a reference for the breeding of aphid-resistant varieties. The flavonoid biosynthesis pathway plays an important role in the response of sorghum aphids and represents an important basis for the biological control of these pests. The results of the spraying experiment provide insights for developing anti-aphid substances in the future.

Hessian Fly (Diptera: Cecidomyiidae) Management Using Seed Treatments in Winter Wheat1

Abstract The Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae), is a potentially severe pest of wheat, Triticum aestivum L. em Thell, in the southeastern United States. Plant resistance is an effective method to control Hessian fly, but when adapted high-yielding varieties with effective resistance are not available, neonicotinoid insecticide seed treatments may provide an alternative method of control of Hessian fly on susceptible varieties of winter wheat. A series of experiments were conducted to examine the efficacy of neonicotinoid seed treatments for control of Hessian fly in winter wheat. Infestations and immature numbers per tiller were assessed during the vegetative stages in autumn and winter and the wheat reproductive stage during the spring. Both imidacloprid 480FS at 0.31 g active ingredient (a.i.)/kg of seed and clothianidin at 0.39 g a.i./kg or higher rates provided consistent reductions in Hessian fly infestations during autumn and early winter. Lower rates were less effective, and they did not provide consistent reductions in autumn infestations. Thiamethoxam was evaluated at one rate in two experiments and was similar in efficacy to imidacloprid and clothianidin at the same rate. None of the seed treatments provided effective control of spring infestations during the wheat reproductive stage. Imidacloprid and clothianidin at rates of 0.31 g a.i./kg of seed or higher rates had a positive yield response in eight of nine comparisons, with an average increase of 285.9 ± 92.7 kg/ha. Neonicotinoid insecticide seed treatments at higher rates provide a useful method for managing Hessian fly on susceptible varieties of winter wheat.

The dynamics of N6-methyladenine RNA modification in resistant and susceptible rice varieties responding to rice stem borer damage.

N6-methyladenosine (m6A) is the most prevalent modification in cellular RNA which orchestrates diverse physiological and pathological processes during stress response. However, the differential m6A modifications that cope with herbivore stress in resistant and susceptible crop varieties remain unclear. Here, we found that rice stem borer (RSB) larvae grew better on indica rice (e.g., MH63, IR64, Nanjing 11) than on japonica rice varieties (e.g., Nipponbare, Zhonghua 11, Xiushui 11). Then, transcriptome-wide m6A profiling of representative resistant (Nipponbare) and susceptible (MH63) rice varieties were performed using a nanopore direct RNA sequencing approach, to reveal variety-specific m6A modifications against RSB. Upon RSB infestation, m6A methylation occurred in actively expressed genes in Nipponbare and MH63, but the number of methylation sites decreased across rice chromosomes. Integrative analysis showed that m6A methylation levels were closely associated with transcriptional regulation. Genes involved in herbivorous resistance related to mitogen-activated protein kinase, jasmonic acid (JA), and terpenoid biosynthesis pathways, as well as JA-mediated trypsin protease inhibitors, were heavily methylated by m6A, and their expression was more pronounced in RSB-infested Nipponbare than in RSB-infested MH63, which may have contributed to RSB resistance in Nipponbare. Therefore, dynamics of m6A modifications act as the main regulatory strategy for expression of genes involved in plant-insect interactions, which is attributed to differential responses of resistant and susceptible rice varieties to RSB infestation. These findings could contribute to developing molecular breeding strategies for controlling herbivorous pests.

Contrasting Performance of Two Winter Wheat Varieties Susceptible to Leaf Rust under Diverse Pathogen Pressure, Fungicide Application, and Cultivation Practices.

This study investigated the relationship between yield, thousand kernel weight (TKW), and crude protein of soft white winter wheat-club variety (Barbee) and soft white winter wheat common variety (Zvezdana) susceptible to leaf rust and powdery mildew under different cultivation practices. Results revealed divergence in associations between yield, TKW, and crude protein loss of winter wheat varieties susceptible to obligate pathogens. Under the same level of leaf rust infection, N-input limited yield loss of the two varieties but not to the same extent. TKW loss was affected only by variety×cultivation practice and was significantly correlated with yield loss (r = -0.727, p = 0.011) and crude protein loss (r = -0.600, p = 0.05) only in club winter wheat. We suspected that Ninput affects the difference in the relationship between yield and TKW loss among varieties. Crude protein and yield loss had a low association (R2 = 18%, p = 0.05). Finally, this study indicated that more attention should be paid to the determination of pathogen pressure that triggers yield loss. It also pointed out that yield, TKW, and crude protein response to fungicides could differ in susceptible varieties. The contribution of fungicide to yield enhancement was highly associated with the specific reaction of the variety to pathogen infection rather than solely the disease level itself.

Identification and Characterization of Polyamine Metabolism in Citrus in Response to 'Candidatus Liberibacter asiaticus' Infection.

Citrus Huanglongbing, one of the most devastating citrus diseases, is caused by 'Candidatus Liberibacter asiaticus' (CLas). Polyamines are aliphatic nitrogen-containing compounds that play important roles in disease resistance and are synthesized primarily by two pathways: an arginine decarboxylation pathway and an ornithine decarboxylation pathway. However, it is unclear whether polyamines play a role in the tolerance of citrus to infection by CLas and, if so, whether one or both of the core polyamine metabolic pathways are important. We used high-performance liquid chromatography and ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry to detect the contents of nine polyamine metabolism-related compounds in six citrus cultivars with varying levels of tolerance to CLas. We also systematically detected the changes in polyamine metabolism-related compounds and H2O2 contents and compared the gene expression levels and the activities of enzymes involved in the polyamine metabolic pathway among healthy, asymptomatic, and symptomatic leaves of Newhall navel oranges infected with CLas. The tolerant and moderately tolerant varieties showed higher polyamine metabolism-related compound levels than those of susceptible varieties. Compared with the healthy group, the symptomatic group showed significantly increased contents of arginine, ornithine, γ-aminobutyric acid, and putrescine by approximately 180, 19, 1.5, and 0.2 times, respectively, and upregulated expression of biosynthetic genes. Arginase and ornithine decarboxylase enzyme activities were the highest in the symptomatic group, whereas arginine decarboxylase and agmatine deiminase enzyme activities were the highest in the asymptomatic group. The two polyamine biosynthetic pathways showed different trends with the increase of the CLas titer, indicating that polyamines were mainly synthesized through the arginine decarboxylase pathway in the asymptomatic leaves and were synthesized via the ornithine decarboxylase pathway in symptomatic leaves. These findings provide new insight into the changes in polyamine metabolism in citrus infected with CLas.

Response of selected peanut commercial cultivars to leaf spot diseases as influenced by fungicide inputs

Early leaf spot (caused by Passalora arachidicola) and late leaf spot (caused by Nothopassalora personata) are the most widespread, damaging foliar diseases of peanuts in the southeastern United States. When left nontreated, both diseases can prematurely defoliate peanuts and reduce peanut yields by up to 70%. Leaf spot diseases are primarily managed through a combination of fungicide applications and cultivar selection. In this study, six field experiments were conducted from 2021 to 2022 in Brewton, Headland, and Tallassee, Alabama, to evaluate the response of ten selected commercial peanut cultivars to various levels of leaf spot pressure as influenced by low- and high-input fungicide programs when compared to nontreated controls. The low input fungicide program included seven applications of chlorothalonil, whereas the high input fungicide program comprised of fluxapyroxad, pyraclostrobin, mefentrifluconazole, flutolanil, bixafen, flutriafol, tebuconazole, and/or chlorothalonil. Effects on leaf spot and pod yields were assessed. Leaf spot severity was higher for TUFRunner™ ‘297’, Georgia-16HO, and FloRun ‘331’, but was lower for AU-NPL 17, Georgia-06G, Georgia-12Y, and Georgia-14N. In terms of yield, leaf spot tolerant varieties showcased superior performance in high disease pressure, whereas susceptible varieties excelled in low disease pressure. Fungicides significantly enhanced the performance of susceptible cultivars under high leaf spot pressure, with marginal impact in low leaf spot pressure. These results highlight the importance of selecting cultivars and fungicide spray programs based on disease pressure to maximize profits.

Adult‐plant resistance to net form net blotch in barley (Hordeum vulgare L.): Durability and genetic control

AbstractThe research reported here was conducted to follow up on observations of durable adult‐plant resistance to net form net blotch in several Australian varieties of barley (Hordeum vulgare L.). Over 11 years, isolates of Pyrenophora teres f. teres were collected and used to inoculate barley varieties. The resistance of five varieties (Clipper, Schooner, Sloop SA, Buloke and Scope) endured until the ninth year. To investigate the genetic control of this durable resistance, doubled haploid lines developed from the F1 generation of a cross between Sloop SA and the susceptible variety Fathom were inoculated with an isolate that appeared fully virulent on Fathom and were evaluated for adult plant resistance. Six quantitative trait loci were mapped: three with resistance from Sloop SA and three with resistance from Fathom. Effects were additive across loci and transgressive segregation provided a few lines with better resistance than Sloop SA. Although the resistance investigated here is no longer effective, insights gained from this research could help guide ongoing efforts in resistance breeding and disease control.

Development of a Greenhouse Assay to Screen Soybean Varieties for Resistance to Aerial Blight Caused by Rhizoctonia solani Anastomosis Group 1-IA.

Aerial blight, caused by the fungus Rhizoctonia solani anastomosis group (AG) 1-IA, is an economically important soybean disease in the mid-Southern United States. Management has relied on fungicide applications during the season, but there is an increasing prevalence of resistance to commonly used strobilurin fungicides and an urgent need to identify soybean varieties resistant to aerial blight. Because the patchy distribution of the pathogen complicates field variety screening, the present study aimed to develop a greenhouse screening protocol to identify soybean varieties resistant to aerial blight. For this, 88 pathogen isolates were collected from commercial fields and research farms across five Louisiana parishes, and 77% were confirmed to be R. solani AG1-IA. Three polymorphic codominant microsatellite markers were used to explore the genetic diversity of 43 R. solani AG1-IA isolates, which showed high genetic diversity, with 35 haplotypes in total and only two haplotypes common to two other locations. Six genetically diverse isolates were chosen and characterized for their virulence and fungicide sensitivity. The isolate AC2 was identified as the most virulent and was resistant to both active ingredients, azoxystrobin and pyraclostrobin, tested. The six isolates were used in greenhouse variety screening trials using a millet inoculation protocol. Of the 31 varieties screened, only Armor 48-D25 was classified as moderately resistant, and plant height to the first node influenced final disease severity. The study provides short-term solutions for growers to choose less susceptible varieties for planting and lays the foundation to characterize host resistance against this important soybean pathogen.

Ai solutions for digital diagnostics of diseases of grain crops (using the example of <i>Pyrenophora teres</i> of winter barley)

The aim of the research is to justify the feasibility of using digital intelligent technologies in forecasting the development of spot blotch in winter barley. The AI solution developed is a binary decision tree capable of predicting scenarios of net blotch development: depressive, moderate, and epiphytotic. To configure the algorithm’s parameters from 2021 to 2023, field and laboratory experiments were conducted at the Federal Scientific Center for Biological Plant Protection. The data preparation involved several stages, including setting up field plots to create an artificial infection background, preparing an inoculum, sowing highly susceptible and resistant winter barley varieties, and artificial inoculation. The selected input factors included the observed degree of leaf damage, type of variety resistance, vegetation phase at the time of primary infection, average relative air humidity during the vegetation phase of infection. The total sample size comprised 144 observations. The trained model demonstrated high classification accuracy on both the training and test datasets, with an accuracy rate exceeding 96 %. Based on a statistical assessment of the factors influencing the development of spot blotch in barley, it is shown that the most influential factor is the current degree of leaf infection (74,3 %), followed by the average relative air humidity (11,9 %), the variety’s resistance to the disease (10,4 %), and the stage development during which infection occurred (3,4 %). The proposed solution holds significant practical importance as it provides new opportunities for the diagnostic process of spot blotch in winter barley. Among these are high diagnostic speed, accuracy in forecast predictions, and applicability in field conditions.

In Vitro Approbation of Microbial Preparations to Shield Fruit Crops from Fire Blight: Physio-Biochemical Parameters.

The need for the increasing geographical spread of fire blight (FB) affecting fruit crops to be addressed led to large-scale chemicalization of the environmental matrices and reduction of plant productivity. The current study aimed to assess the effects of novel biopreparations at different exposure durations on photosynthetic pigment content and antioxidant enzyme activity in leaves of apple and pear varieties with varying levels of resistance to FB. Biopreparations were formulated from a cultural broth containing Lacticaseibacillus paracasei M12 or Bacillus amyloliquefaciens MB40 isolated from apple trees' phyllosphere. Aseptic leaves from blight-resistant (endemic Malus sieversii cv. KG10), moderately resistant (Pyrus pyraster cv. Wild), and susceptible (endangered Malus domestica cv. Aport and Pyrus communis cv. Shygys) varieties were employed. The impact of biopreparations on fruit crop antioxidant systems and photosynthetic apparatuses was investigated in vitro. Study results indicated that FB-resistant varieties exhibit enhanced adaptability and oxidative stress resistance compared to susceptible ones. Plant response to biopreparations varied based on the plant's initial FB sensitivity and exposure duration. Indeed, biopreparations improved the adaptive response of the assimilation apparatus, protein synthesis, and catalase and superoxide dismutase activity in susceptible varieties, suggesting that biopreparations have the potential for future commercialization to manage FB in fruit crops.

Virulence Comparison of a Comprehensive Panel of Xylella fastidiosa Pierce's Disease Isolates from California.

Xylella fastidiosa, the causal agent of Pierce's disease of grapevine, has been found in all major grape-growing regions in California, U.S.A. Large collections of X. fastidiosa isolates are available from these areas, which enable comparative studies of pathogen genetic traits and virulence. Owing to the significant resource requirements for experiments with X. fastidiosa in grapevine, however, most studies use only a single isolate to evaluate disease, and it is not clear how much variability between isolates impacts disease development in experimental or natural settings. In this study, a comprehensive panel of X. fastidiosa isolates from all California grape-growing regions was tested for virulence in susceptible grapevine and in the model host plant, tobacco. Seventy-one isolates were tested, 29 in both grapevine and tobacco. The results of this study highlight the inherent variability of inoculation experiments with X. fastidiosa, including variation in disease severity in plants inoculated with a single isolate, and variability between experimental replicates. There were limited differences in virulence between isolates that were consistent across experimental replicates, or across different host plants. This suggests that choice of isolate within the X. fastidiosa subsp. fastidiosa Pierce's disease group may not make any practical difference when testing in susceptible grape varieties, and that pathogen evolution has not significantly changed virulence of Pierce's disease isolates within California. The location of isolation also did not dictate relative disease severity. This information will inform experimental design for future studies of X. fastidiosa in grapevine and provide important context for genomic research.

Identification of potential morpho-biochemical determinants conferring salt tolerance in wheat (Triticum aestivum L.) through seedling- and -reproductive stage phenotyping

To optimize a reproductive-stage-specific phenotyping protocol and isolate potential determinants conferring salinity tolerance in wheat, two consecutive experiments were conducted using salt-tolerant varieties (Binagom-1 and BARI Gom 25) and a sensitive variety (BARI Gom 20). In the first experiment, seedlings were grown hydroponically, and 14-day-old seedlings were subjected to two different levels of salt stress (EC=12 dS/m and 16 dS/m) for 7 days. Based on the results of tolerant and susceptible varieties, parameters such as root and shoot weight, shoot Na+/K+ ratio, chlorophyll content, proline content, methylglyoxal content, H2O2 content and lipid peroxidation content and the activities of enzymes such as ascorbate peroxidase, peroxidase, and glyoxalase I were considered as potential determinants of salt tolerance. The second experiment employed four leaf cutting treatments under both control and salinity stress conditions. Seedlings were grown in perforated pots filled with field soil, and at the heading stage, plants were subjected to salt stress (12 dS/m) after trimming as indicated. The combined analysis of control and salt stress data obtained from setup B reflected a significant decrease in yield and yield-attributing traits; however, a lesser decrease was observed in tolerant varieties. Correlation studies revealed that grain yield per spike exhibited a significant positive correlation with the number of seeds per spike, spike weight, plant height, and days to first flowering under both stress and control conditions. Additionally, different stress tolerance indices also supported the results of reproductive stage phenotyping. However, further studies will be required to tag the genes/QTLs controlling salinity tolerance in wheat at various growth phases.

MONITORING, POPULATION DYNAMICS AND INFESTATION RATE OF RED PALM WEEVIL IN DIFFERENT LOCAL DATE PALM VARIETIES IN BAHAWALPUR

The date palm, or Phoenix dactylifera L., is a valuable fruit crop and source of income for many nations. It is a member of the Arecaceae family of palm trees. Red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier, 1790) is an invasive pest that causes damage to palm trees worldwide by eating their stems inside. The objective of this study is to identify susceptible and resistant varieties among as well as identify the population dynamics of R. ferrugineus. Our results showed that most affected variety was Khurma in both age date palm e.g., five-ten old plants and in eleven-fifteen years old. While most superior least effected variety was Begum Jangi among Zhaidi, Aseel, Begum Jangi, Haleeni, and Shamran with no population. The most vulnerable date palm variety is Khurma. For both immature and mature R. ferrugineus, January through March and October through December are the ideal months to execute management measures. According to recent research, the Bahawalpur region needs to introduce resistant date palm varieties.

Silicon induces ROS scavengers, hormone signalling, antifungal metabolites, and silicon deposition against brown stripe disease in sugarcane.

Bipolaris setariae is known to cause brown stripe disease in sugarcane, resulting in significant yield losses. Silicon (Si) has the potential to enhance plant growth and biotic resistance. In this study, the impact of Si on brown stripe disease was investigated across susceptible and resistant sugarcane varieties, utilizing four Si concentrations (0, 15, 30, and 45 g per barrel of Na2SiO3·5H2O). Si significantly reduced the incidence of brown stripe disease (7.41-59.23%) and alleviated damage to sugarcane growth parameters, photosynthetic parameters, and photosynthetic pigments. Submicroscopic observations revealed that Si induced the accumulation of silicified cells in leaves, reduced spore accumulation, decreased stomatal size, and protected organelles from B. setariae damage. In addition, Si increased the activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase), reduced reactive oxygen species production (malondialdehyde and hydrogen peroxide) and modulated the expression of genes associated with hormone signalling (PR1, TGA, AOS, AOC, LOX, PYL8, and SnRK2), leading to the accumulation of abscisic acid and jasmonic acid and inhibiting SA synthesis. Si also activated the activity of metabolism-related enzymes (polyphenol oxidase and phenylalanine ammonia lyase) and the gene expression of PAL-dependent genes (PAL, C4H, and 4CL), regulating the accumulation of metabolites, such as chlorogenic acid and lignin. The antifungal test showed that chlorogenic acid (15ug μL-1) had a significant inhibitory effect on the growth of B. setariae. This study is the first to demonstrate the inhibitory effect of Si on B. setariae in sugarcane, highlighting Si as a promising and environmentally friendly strategy for managing brown stripe disease.

Identification of the Downy Mildew Resistant Sources in Sunflower

Four different evaluation trials were conducted in the field between 2017 and 2020, with varied numbers of genotypes, to evaluate the performance of sunflower genotypes for agromorphological features and resistance to Sunflower Downy Mildew (SDM) at Latur, Maharashtra, India. A validation experiment was carried out in 2021–2022, using artificial screening in National Diseased Plot Screening Facility at Latur, to screen a small number of accessions that had previously shown resistance to SDM during 2017-2020. The released variety "Morden," also susceptible check showed at least 60% of the SDM incidence for four years. This suggests that Plasmopara halstedii spores could be present in the experimental soils, which increases the variety's susceptibility to SDM disease. Out of the tree genotypes that were reported to be resistant in field screening viz., GMU-481 (GP1 909 genotype), Ec-198078, and RHA 1-1 (selection) only two GMU-481 (GP1 909) and Ec-198078 were verified to be resistant under artificial screening in 2021–2022 and can be designated as sources of resistance for SDM disease. These two genotypes with resistance to SDM could be used in future breeding attempts and as potential gene donors for SDM.

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.

Economically Imperative Ananas comosus Diseases, Status, and Its Control Measures Documented in Producing Countries

Ananas comosus, commonly known as pineapple, is a fruit with a large potential market as a commodity and commercial fruit. Numerous pests and diseases affect pineapple, directly or indirectly, by lowering the quality and quantity. The fungal causative agents, namely Fusarium ananatum and Thalaromyces stolii (previously named Penicillium funiculosum), cause fruitlet core rot (FCR) and fusariosis by Fusarium guttiforme. Bacteria heart rot (BHR) is an infection by Erwinia chrysanthemi, newly known as Dickeya zeae. Nevertheless, the mealybug wilt of pineapple (MWP) is another pineapple treat to susceptible pineapple varieties caused by pineapple mealybug wilt-associated viruses (PMWaVs). Other diseases include destruction caused by pathogenic nematodes. This review discusses the status of these diseases and the control measures that greatly affect the economy of pineapple-producing countries due to the economic significance of these crops. Growers need up-to-date information on the identity of the diseases that affect pineapple crops in the various countries that produce them to effectively manage the diseases in the field.

Global changes in gene expression during compatible and incompatible interactions of faba bean (Vicia faba L.) during Orobanche foetida parasitism.

Orobanche foetida Poiret is the main constraint facing faba bean crop in Tunisia. Indeed, in heavily infested fields with this parasitic plant, yield losses may reach 90%, and the recent estimation of the infested area is around 80,000 ha. Identifying genes involved in the Vicia faba/O. foetida interaction is crucial for the development of effective faba bean breeding programs. However, there is currently no available information on the transcriptome of faba bean responding to O. foetida parasitism. In this study, we employed RNA sequencing to explore the global gene expression changes associated with compatible and incompatible V. faba/O. foetida interactions. In this perspective, two faba bean varieties (susceptible and resistant) were examined at the root level across three stages of O. foetida development (Before Germination (BG), After Germination (AG) and Tubercule Stage (TS)). Our analyses presented an exploration of the transcriptomic profile, including comprehensive assessments of differential gene expression and Gene Ontology (GO) enrichment analyses. Specifically, we investigated key pathways revealing the complexity of molecular responses to O. foetida attack. In this study, we detected differential gene expression of pathways associated with secondary metabolites: flavonoids, auxin, thiamine, and jasmonic acid. To enhance our understanding of the global changes in V. faba response to O. foetida, we specifically examined WRKY genes known to play a role in plant host-parasitic plant interactions. Furthermore, considering the pivotal role of parasitic plant seed germination in this interaction, we investigated genes involved in the orobanchol biosynthesis pathway. Interestingly, we detected the gene expression of VuCYP722C homolog, coding for a key enzyme involved in orobanchol biosynthesis, exclusively in the susceptible host. Clearly, this study enriches our understanding of the V. faba/O. foetida interaction, shedding light on the main differences between susceptible and resistant faba bean varieties during O. foetida infestation at the gene expression level.

Oschib1 gene encoding a GH18 chitinase confers resistance against sheath blight disease of rice caused by Rhizoctonia solani AG1-IA.

Sheath blight disease of rice caused by Rhizoctonia solani AG1-IA, is a major fungal disease responsible for huge loss to grain yield and quality. The major limitation of achieving persistent and reliable resistance against R. solani is the governance of disease resistance trait by many genes. Therefore, functional characterization of new genes involved in sheath blight resistance is necessary to understand the mechanism of resistance as well as evolving effective strategies to manage the disease through host-plant resistance. In this study, we performed RNA sequencing of six diverse rice genotypes (TN1, BPT5204, Vandana, N22, Tetep, and Pankaj) from sheath and leaf tissue of control and fungal infected samples. The approach for identification of candidate resistant genes led to identification of 352 differentially expressed genes commonly present in all the six genotypes. 23 genes were analyzed for RT-qPCR expression which helped identification of Oschib1 showing differences in expression level in a time-course manner between susceptible and resistant genotypes. The Oschib1 encoding classIII chitinase was cloned from resistant variety Tetep and over-expressed in susceptible variety Taipei 309. The over-expression lines showed resistance against R. solani, as analyzed by detached leaf and whole plant assays. Interestingly, the resistance response was correlated with the level of transgene expression suggesting that the enzyme functions in a dose dependent manner. We report here the classIIIb chitinase from chromosome10 of rice showing anti-R. solani activity to combat the dreaded sheath blight disease.