Vacuolar Processing Enzymes Modulating Susceptibility Response to Fusarium oxysporum f. sp. cubense Tropical Race 4 Infections in Banana

Fusarium oxysporum f. sp. cubense tropical race 4 (FocTR4) is a destructive necrotrophic fungal pathogen afflicting global banana production. Infection process involves the activation of programmed cell death (PCD). In this study, seven Musa acuminata vacuolar processing enzyme (MaVPE1–MaVPE7) genes associated with PCD were successfully identified. Phylogenetic analysis and tissue-specific expression categorized these MaVPEs into the seed and vegetative types. FocTR4 infection induced the majority of MaVPE expressions in the susceptible cultivar “Berangan” as compared to the resistant cultivar “Jari Buaya.” Consistently, upon FocTR4 infection, high caspase-1 activity was detected in the susceptible cultivar, while low level of caspase-1 activity was recorded in the resistant cultivar. Furthermore, inhibition of MaVPE activities via caspase-1 inhibitor in the susceptible cultivar reduced tonoplast rupture, decreased lesion formation, and enhanced stress tolerance against FocTR4 infection. Additionally, the Arabidopsis VPE-null mutant exhibited higher tolerance to FocTR4 infection, indicated by reduced sporulation rate, low levels of H2O2 content, and high levels of cell viability. Comparative proteomic profiling analysis revealed increase in the abundance of cysteine proteinase in the inoculated susceptible cultivar, as opposed to cysteine proteinase inhibitors in the resistant cultivar. In conclusion, the increase in vacuolar processing enzyme (VPE)-mediated PCD played a crucial role in modulating susceptibility response during compatible interaction, which facilitated FocTR4 colonization in the host.

Differential Gene Expression Analysis of Resistant and Susceptible Flax Cultivars in Response to Fusarium oxysporum Stress

A plant’s early response to pathogen stress is a vital indicator of its disease resistance. In order to study the response mechanism of resistant and susceptible flax cultivars to Fusarium oxysporum f. sp. lini (Foln), we applied RNA-sequencing to analyze transcriptomes of flax with Foln 0.5, 2 and 8 hours post inoculation (hpi). We found a significant difference in the number of differential expression genes (DEGs) between resistant and susceptible flax clutivars. The number of DEGs in the Fusarium-resistant cultivar increased dramatically at 2 hpi, and a large number of DEGs participated in the Fusarium-susceptible cultivar response to Foln infection 0.5 hpi. GO enrichment analysis determined that the up-regulated DEGs of both flax cultivars were enriched such as oxidoreductase activity and oxidation-reduction process. At the same time, the genes involved in diterpenoid synthesis were up-regulated in resistant cultivar, while those involved in extracellular region, cell wall and organophosphate ester transport were down-regulated in susceptible cultivar. KEGG enrichment analysis showed the genes encoded WRKY 22 and WRKY33 which involved in MAPK signaling pathway were up-regulated expressed in S-29 and down-regulated expressed in R-7, negatively regulated the disease resistance of flax; The genes encoded Hsp 90 family which in involved in plant pathogen interaction pathway were up-regulated in R-7 and down-regulated in S-29, which positively regulated the disease resistance of flax; The genes encoded MYC2 transcription factor and TIFY proteins which involved in plant hormone signaling pathway were up-regulated in R-7, and regulated the jasmonic acid metabolism of flax and the signal transduction of plant hormones. Meanwhile seven regulatory genes with the most correlation were screened out, Among Lus10025000.g and Lus10026447.g regulated other genes expressed both in plant hormone signal transduction pathway and MAPK signal pathway. In conclusion, these findings will facilitate further studies on the function of these candidate genes in flax of response to Fusarium stress, and the breeding of disease-resistant flax cultivar.

Identification and Characterization of Verticillium nonalfalfae-Responsive MicroRNAs in the Roots of Resistant and Susceptible Hop Cultivars

MicroRNAs are 21- to 24-nucleotide-long, non-coding RNA molecules that regulate gene expression at the post-transcriptional level. They can modulate various biological processes, including plant response and resistance to fungal pathogens. Hops are grown for use in the brewing industry and, recently, also for the pharmaceutical industry. Severe Verticillium wilt caused by the phytopathogenic fungus Verticillium nonalfalfae, is the main factor in yield loss in many crops, including hops (Humulus lupulus L.). In our study, we identified 56 known and 43 novel miRNAs and their expression patterns in the roots of susceptible and resistant hop cultivars after inoculation with V. nonalfalfae. In response to inoculation with V. nonalfalfae, we found five known and two novel miRNAs that are differentially expressed in the susceptible cultivar and six known miRNAs in the resistant cultivar. Differentially expressed miRNAs target 49 transcripts involved in protein localization and pigment synthesis in the susceptible cultivar, whereas they are involved in transcription factor regulation and hormone signalling in the resistant cultivar. The results of our study suggest that the susceptible and resistant hop cultivars respond differently to V. nonalfalfae inoculation at the miRNA level and that miRNAs may contribute to the successful defence of the resistant cultivar.

Defense Response to Hemileia vastatrix in Susceptible Grafts onto Resistant Rootstock of Coffea arabica

The use of resistant cultivars and fungicides are common methods to control coffee leaf rust (CLR), the main disease that affects the Arabica coffee crop. In this study, we evaluated the response of grafted and ungrafted plants during the early stage of Hemileia vastatrix infection. We used ungrafted plants of Oro Azteca (resistant cultivar) and Garnica (susceptible cultivar), and grafted plants, combining both as rootstock and graft (Garnica/Oro Azteca and Oro Azteca/Garnica). All plants were inoculated with H. vastatrix uredospores, and we quantified the development of fungal structures in the leaf tissue of inoculated plants using qRT-PCR to measure relative expression of two pathogenesis recognition genes (CaNDR1 and CaNBS-LRR) and three genes associated with the salicylic acid (SA) pathway (CaNPR1, CaPR1 and CaPR5). In Garnica grafted on Oro Azteca, the fungal structures recorded were significantly less than in Garnica ungrafted plants. In addition, the expression of defense-related genes in grafted plants was higher than in ungrafted plants. Our results indicate that the defense response to CLR is strongly influenced by the rootstock employed.

Identification and Characterization of Verticillium Nonalfalfae-responsive Micrornas in the Roots of Resistant and Susceptible Hop Cultivars

Micro RNAs are 21- to 24-nucleotide-long, non-coding RNA molecules that regulate gene expression at the post-transcriptional level. They can modulate various biological processes, including plant response and resistance to fungal pathogens. Hops are grown for use in the brewing industry and recently also for pharmaceutical industry. Severe Verticillium wilt caused by the phytopathogenic fungus Verticillium nonalfalfae, is the main factor in yield loss in many crops, including hops (Humulus lupulus L.). In our study, we identified 56 known and 43 novel miRNAs and their expression patterns in the roots of susceptible and resistant hop cultivars after inoculation with V. nonalfalfae. In response to inoculation with V. nonalfalfae, we found five known and two novel miRNAs that are differentially expressed in the susceptible cultivar and six known miRNAs in the resistant cultivar. Differentially expressed miRNAs target 49 transcripts involved in protein localization and pigment synthesis in the susceptible cultivar, whereas they are involved in transcription factor regulation and hormone signalling in the resistant cultivar. The results of our study suggest that the susceptible and resistant hop cultivars respond differently to V. nonalfalfae inoculation at the miRNA level and that miRNAs may contribute to the successful defence of the resistant cultivar.

Defense-Related Gene Expression Following an Orthotospovirus Infection Is Influenced by Host Resistance in Arachis hypogaea

Planting resistant cultivars is the most effective tactic to manage the thrips-transmitted tomato spotted wilt orthotospovirus (TSWV) in peanut plants. However, molecular mechanisms conferring resistance to TSWV in resistant cultivars are unknown. In this study, transcriptomes of TSWV-susceptible (SunOleic 97R) and field-resistant (Tifguard) peanut cultivars with and without TSWV infection were assembled and differentially expressed genes (DEGs) were compared. There were 4605 and 2579 significant DEGs in SunOleic 97R and Tifguard, respectively. Despite the lower number of DEGs in Tifguard, an increased proportion of defense-related genes were upregulated in Tifguard than in the susceptible cultivar. Examples included disease resistance (R) proteins, leucine-rich repeats, stilbene synthase, dicer, and calmodulin. Pathway analysis revealed the increased downregulation of genes associated with defense and photosynthesis in the susceptible cultivar rather than in the resistant cultivar. These results suggest that essential physiological functions were less perturbed in the resistant cultivar than in the susceptible cultivar and that the defense response following TSWV infection was more robust in the resistant cultivar than in the susceptible cultivar.

Determining an effective and economic fungicide spray schedule for reducing blast of wheat

Wheat blast, caused by the fungus Magnaporthe oryzae pathotype Triticum (MoT), constitutes one of the major obstacles to the expansion of wheat production in Bangladesh. In the absence of resistant variety, fungicide control is the first-hand effort. Determining an effective and economic fungicide spray schedule in controlling blast disease of wheat was aimed. Ten fungicides were tested during two consecutive cropping seasons of 2018-2019 to 2019-2020. The wheat plants of blast susceptible cultivar BARI Gom 26 were inoculated with spores (107 spores ml-1) of MoT at pre-heading stage of wheat (52 days age). Fungicides were applied both before inoculation and after the appearance of blast symptoms in cocktail for three times starting from booting of wheat at 7 days interval. Plants received the combination of Filia (Tricyclazole 40% + Propiconazole 12.5%) and Seltima (Pyraclostrobin 10%) had significantly lower blast incidence and severity (1.23% and 3.33%) against untreated plants. Cocktail of Nativo and Trooper (Tricyclazole 75 wp) proved 2nd best curative measure. Application of Nativo (Tebuconazole 50% + Trifloxystrobin 25%) alone ranked third in its efficacy. The fungicide spray schedule covered booting, pre-heading and heading stages of wheat. The results indicate a mixture of Tebuconazole + Tricyclazole + Pyraclostrobin is more effective (97% blast reduction) and economic (BCR 1.45) than a single compound application in reducing incidence and severity of wheat blast. Int. J. Agril. Res. Innov. Tech. 11(1): 10-16, June 2021

Plant lipid metabolism in susceptible and tolerant soybean (Glycine max) cultivars in response to Phytophthora sojae colonization and infection

Soybean is one of the most cultivated crops globally and a staple food for much of the world's population. The annual global crop losses due to infection by the Phytophthora sojae are currently estimated at approximately $2B USD, yet we have limited understanding of the role of lipid metabolism in the adaptative strategies used to limit infection and crop loss. We employed a multi-modal lipidomics approach to investigate how soybean cultivars remodel their lipid metabolism to successfully limit infection by Phytophthora sojae. Both the tolerant and susceptible soybean cultivars showed alterations in lipid metabolism in response to Phytophthora sojae infection. Relative to non-inoculated controls, induced accumulation of stigmasterol was observed in the susceptible cultivar whereas, induced accumulation of phospholipids and glycerolipids occurred in tolerant soybean cultivar. We have generated a comprehensive metabolic map of susceptible and tolerant soybean root and stem lipid metabolism to identify lipid modulators of host immune or tolerance response to Phytophthora sojae infection and identified potential pathways and unique lipid biomarkers like TG(15:0/22:0/22:5), TG(10:0/10:0/10:0), TG(10:0/10:0/14:0), DG(18:3/18:3), DG(16:0/18:3) and DG(24:0/18:2) as possible targets for the development of future plant protection solutions.

Demonstration field experiment on testing nematode-resistant potato varieties in the Vladimir Region

The purpose of the research is a demonstration field experiment on testing nematode-resistant potato varieties on a collective farm in focal point of golden potato nematode (GPN).Materials and methods. A demonstration field experiment on testing 7 nematode-resistant and 2 susceptible potato varieties was performed in the village of Parakhino, Gus-Khrustalny District, Vladimir Region, in a small family garden with significant evidences of potato globoderosis. The family garden was divided into 27 plots. The plot area was 100 m2 . In spring and autumn, 500 cm3 soil samples were taken from each plot. The soil samples were studied by the flotation funnel method. In growing season, we measured the height of plants, counted the number of stems, estimated the color, considered the uniformity and projected coverage of grass stand of the soil, assessed the globoderosis development, and determined the number of female GPN and their development on plant roots. During the harvesting period, we took into account the number and weight of potato tubers (standard and nonstandard) in 25 plants on each plot and the number of plants on the plot, and determined potato yields. We calculated the biological and economic effectiveness of growing nematode-resistant potato varieties.Results and discussion. The demonstration field experiments of 7 nematode-resistant potato varieties using modern mechanized potato cultivation techniques in the globoderosis focus faced by high infective rate (pre-plant density of the GPN population was 9.7–10 thousand eggs and larvae per 100 cm3 of soil) showed that the nematode-resistant varieties of Saturna, Lady Rosetta, Lady Claire, Malinovka, Latonna, Skarb, Zhukovsky Ranny surpassed susceptible cultivar Udacha (standard) in biological effectiveness (57–85%), economic effectiveness (4.9–134%) and economic benefit (87–409%). In susceptible cultivars Udacha and Germes, the globoderosis development was above 53%. In the tested nematode-resistant cultivars, the globoderosis development was poorly expressed (15–26%). Nematode-resistant cultivars Lady Claire, Lady Rosetta and Saturna, which showed the highest levels of profitability, economic efficiency, and high rates of decrease in the GPN population density in the soil can be recommended for cultivation in the fields of the Rossiya agricultural company. Susceptible cultivar Germes, which has shown good performance in terms of economic effectiveness and benefit can be recommended for cultivation in the crop rotation fields of the Rossiya agricultural company. Nematode-resistant cultivars Malinovka, Skarb, Latonna and Zhukovsky Ranny, which showed less economic effectiveness and benefit as compared to potato varieties for chips can be recommended for cultivation in private plots if cultivated using modern technology.

Plant lipid metabolism in response to Phytophthora sojae infection in susceptible and tolerant soybean cultivars

Soybean is one of the most cultivated crops globally and a staple food for much of the world's population. The annual global crop losses due to infection by the Phytophthora sojae are currently estimated at approximately $2B USD, yet we have limited understanding of the role of lipid metabolism in the adaptative strategies used to limit infection and crop loss. We employed a multi-modal lipidomics approach to investigate how soybean cultivars remodel their lipid metabolism to successfully limit infection by Phytophthora sojae. Both the tolerant and susceptible soybean cultivars showed alterations in lipid metabolism in response to Phytophthora sojae infection. Relative to non-inoculated controls, induced accumulation of stigmasterol was observed in the susceptible cultivar whereas, induced accumulation of phospholipids and glycerolipids occurred in tolerant soybean cultivar. We have generated a comprehensive metabolic map of susceptible and tolerant soybean root and stem lipid metabolism to identify lipid modulators of host immune or tolerance response to Phytophthora sojae infection and identified potential pathways and unique lipid biomarkers like TG(15:0/22:0/22:5), TG(10:0/10:0/10:0), TG(10:0/10:0/14:0), DG(18:3/18:3), DG(16:0/18:3) and DG(24:0/18:2) as possible targets for the development of future plant protection solutions.