Agri Gene最新文献

‘Candidatus Liberibacter asiaticus’ (Las) is one of the most destructive plant pathogens associated with citrus huanglongbing (HLB). Las is a Gram-negative, as yet uncultured, alpha-Proteobacterium and is transmitted by the Asian citrus psyllid, Diaphorina citri. A putative protein (designated as LasP₂₃₅) was identified in the prophage region of the Las psy62 genome. LasP₂₃₅ gene encodes a 123 amino-acid protein which is predicted to localize to the plant nucleus. Green fluorescence protein (GFP)-fused with LasP₂₃₅ appeared to accumulate in Nicotiana benthamiana cell nuclei following Agrobacterium-mediated transient expression. To eliminate potential side effects of GFP protein, LasP₂₃₅ alone was inserted into a binary vector for transforming Carrizo citrange (Citrus sinensis X Poncirus trifoliata). Transgenic Carrizo plants were obtained. LasP₂₃₅ gene integration was confirmed by PCR and the levels of LasP₂₃₅ expression were compared by RT-quantitative PCR (RT-qPCR). Some LasP₂₃₅ expressing Carrizo plants displayed HLB-like symptoms, including leaf chlorosis and plant growth retardation. LasP₂₃₅ gene expression levels, determined by RT-qPCR, correlated with HLB-like symptoms. Furthermore, The expression of LasP₂₃₅ was upregulated in chlorotic tissue compared to green tissue of Las-infected, blotchy mottled leaves of lemon and grapefruit. Transcriptome analysis revealed that metabolic pathways and biosynthesis of secondary metabolites were significantly altered in transgenic citrus expressing the LasP₂₃₅ effector. Further investigation of LasP₂₃₅, especially research focused on identifying its binding protein in citrus, may provide a way to block Las infection.

Contagious ecthyma is a zoonotic disease, caused by the Orf virus (ORFV) affecting sheep, goats, and humans and is widely distributed across the world. In this study, we have investigated fifteen recent ORFV outbreaks in Black Bengal goats occurred in the Odisha state of India. The outbreaks were characterized by the high rates of morbidity (reaching up to 100%) without any mortality in the infected goats. Molecular and phylogenetic analysis of four ORFV genes such as ORFV011, ORFV020, ORFV059, and ORFV108 was performed, which revealed that current isolates were closely related to Assam, China, Bangalore, and Meghalaya isolates, respectively, with some unique mutations. Finally, to get an insight into the global ORFV evolution pattern, population genetics parameters such as nucleotide diversity, haplotype diversity, selection pressure, and neutrality among these genes were estimated by comparing the GenBank database. We observed low haplotype as well as nucleotide diversity and purifying selection implying ORFV evolution globally.

The relationship between the diversity of chemosensory proteins (CSPs) and their limited gene repertoire is of great interest. We have previously demonstrated that mRNA editing is responsible for this diversity. In this report, we describe hypotheses we have developed from phylogenetic analyses of CSP genes and RNA variants of the silkworm moth, Bombyx mori. Our analysis is based on previously published DNA/RNA/peptide sequencing data of the different variants from different tissues (Xuan et al., 2014, Xuan et al., 2016). We find and describe conventional A-to-I RNA editing, and C-to-U/U-to-C editing events in different CSP variants and pinpoint loci we believe encode the ADAR and ADAT enzymes and variants thereof that are responsible for these events. We also describe several non-conventional editing events including G-to-I and C-to-I, suggesting the existence of a multitude of mutation mechanisms in insects as found in microbes, viruses and plants. In particular, our phylogenetic analysis indicates that some mRNA sequences are more closely related to edited mRNA than to the gene sequence and shows evidence of tissue-specific DNA-dependent (Dd) or RNA-dependent (Rd) mutations depending on the gene. These descriptive findings in the silkworm are useful for molecular evolution of Dd-and Rd-RNA polymerases in relation with a specific gene family, as well as evolutionary biology and adaptation of RNA, cell, tissue or organism to new environment.

Most studies on plant-insect interactions focus on the aboveground parts of plants, but the knowledge regarding the belowground interactions is increasing. Soil pests are at least equally dangerous to plant health and elicit plant defense mechanisms as well. Wireworms (Coleoptera: Elateridae) are common polyphagous soil pests of various crops, including economically relevant crops such as maize and potatoes. Their management with pesticides is often not successful or sustainable, and more research on biological alternatives is required. We aim at providing an overview of biological control methods under development or commercially available. Little is known about the natural enemies of wireworms, and the available work is often limited to laboratory experiments. The interest for using using microorganisms as biocontrol agent is increasing, and entomopathogenic fungi, nematodes, and bacteria represent promising alternatives to pesticides. The review discusses the combination of attractive semiochemicals with biological agents to improve wireworm monitoring and control, as well as research advances on these fronts.

Flacherie is a widely prevalent disease in silkworms that causes huge economic losses to the sericulture industry. The Bombyx mori bidensovirus (BmBDV) is one of the causative agents of this disease. A major gene, nsd-2 (non-susceptibility to densovirus-2), a putative BmBDV receptor conferring resistance under recessive mutation condition has previously been identified. The natural deletion occurring in the nsd-2 gene has contributed to the evolution of BmBDV resistant silkworm breeds. However, nsd-2 has not yet been utilized as a marker or as a transgene for the development of BmBDV resistant breeds. In this study, we have demonstrated the use of the functional marker, nsd-2 for the development of absolute BmBDV resistant productive mulberry silkworm breeds. We screened 49 productive bivoltine breeds and identified 28 breeds carrying the nsd-2 resistant allele. Sixteen breeds having the resistant allele were identified in heterozygous condition at the nsd-2 locus, so these breeds could not be identified as resistant carrier when challenged with virus inoculation. Further, we have shown that selecting nsd-2 resistant allele in homozygous condition, at the nsd-2 locus is sufficient for the development of BmBDV resistant productive breeds like CSR6-R and CSR26-R. We have also validated the developed breeds for resistance to BmBDV through bioassays and found absence of viral genome at the molecular level thereby demonstrating complete resistance upon BmBDV infection, in the developed breeds.

Yellow stem borer (YSB), Scirpophaga incertulas, (Walker) is one the most destructive pests in rice causing severe yield loss. Of the many approaches for managing insect pests, RNA interference (RNAi) is a viable option which can be employed by targeting the key insect genes that are involved in host-pest interactions. In this study, Acetylcholinesterase (AChE), a key gene of YSB was targeted for silencing through a RNAi approach. Specifically designed dsRNA from the alpha/beta hydrolase fold of YSB AChE was labeled with 5’ FAM (Fluorescent dye) and used in this study. The efficacy of dsRNA was evaluated through a systematic insect bioassay. Larval growth and mortality were observed for a period of 15 days after the treatment through the cut stem assays. The reduced larval length and weight were observed in the dsRNA treated samples which were correlated with the low gene expression compared to the untreated controls. These results suggest that AChE is a potential target for RNAi approach in insects.

In the present study, a novel gene designated as CmZNF384L, of which partial transcript (GenBank accession number JK487591) was identified previously to encode a zinc finger 384-like protein in suppression subtractive hybridization studies, was examined for its genetic feature and gene expression under normoxic and hypoxic conditions in Clarias magur. The largest ORF of assembled contig contains 1365 nucleotide residues and encodes a protein of 454 amino acids with eight Kru¨ppel-type zinc finger C2H2 domains, which is considered as a member of beta-beta-alpha zinc finger superfamily. Bioinformatic analysis of protein-protein interactions by STRING 10.0 yielded the highest score or confidence on its interaction with COL1A1. Gene expression analyses revealed constitutive transcript expression under normoxia in the six tissues examined, while the transcript levels were significantly higher, after both short-term (experimental) and long-term (natural) hypoxia in head kidney and heart tissues, after short-term hypoxia in spleen, and after long-term hypoxia in liver. No significant difference of transcript levels was observed in muscle and brain tissues between normoxic and hypoxic conditions. The pattern, especially increased transcript level in heart to hypoxia, may indicate critical role of CmZNF384L in the molecular mechanism of highly complex hypoxia tolerance in the species.

Efforts have been made to engineer cotton to achieve resistance to the boll weevil, which is one of the most important pests impacting cotton production in the Americas. The insects feed on flowers and immature cotton bolls. Strategies for expressing insecticide proteins must be associated with a strong expression in these tissues. The expression of the gus gene driven by the ACT2 promoter from Arabidopsis thaliana was compared to the 35SCaMV promoter in leaves, roots, petals and fiber of transgenic cotton plants. Fluorometric and histochemical analyses have shown that the ACT2 promoter produced a strong expression in floral and boll tissues, including pollen, petals, ovules and fiber. It revealed the potential of using the ACT2 promoter to express genes involved with boll weevil resistance.

Identification of genes responsible for pest resistance in maize will assist with breeding attempts to reduce crop losses and hazards due to toxins produced by mold infecting ears. A gene coding for a defensin-like gene was cloned from an inbred reported to be resistant to Fusarium proliferatum and Fusarium verticillioides ear rot, based on its location in a QTL associated with resistance to those and other species of ear rot molds that produce mycotoxins. The gene was expressed transgenically in maize callus and the construct presence confirmed in transformants by PCR analysis and by detection with antibody made to a portion of the protein. Positive transformants were more resistant to corn earworms (Helicoverpa zea) and fall armyworms (Spodoptera fruigperda) as indicated by significantly lower weights compared to control callus expressing a β–glucuronidase (GUS) gene. Positive transformants also had significantly less visible growth of F. proliferatum and F. verticillioides, but not Fusarium graminearum, than controls. This indicates for the first time a defensin that is active against both insects and fungi, thereby allowing for more effective breeding for resistance to both major classes of pests attacking maize.

At altitudes >1500 m, measurements of mean pulmonary arterial pressures (mPAP; mmHg) are a measure of pulmonary hypertension (PH) in cattle. Genotypes of a G/A single nucleotide polymorphism (SNP; rs208684340) in the endothelial PAS domain protein 1 (EPAS1) gene were determined for mPAP categories (low, moderate, high) on Angus cattle. The A allele of this SNP was postulated to be associated with altitude-induced PH. The first objective was to estimate allele and genotypic frequencies in Angus cattle at high- (elevation 1850 to 2800 m) and low-altitude (elevation 91 to 1192 m) ranches (n = 118; random sample of 1275). Percent of cattle at these low elevation ranches with genotypes G/G, G/A, and A/A were 64.4, 33.9, and 1.7%, respectively, and a minor allele frequency (MAF; A allele) of 18.6%. Bulls, steers, and heifers (n = 691) from 4 high-altitude Angus herds in Colorado and Wyoming were genotyped. Percent of cattle with genotypes G/G, G/A, and A/A were 48.6, 34.3, and 17.1%, respectively, with a MAF of 34.2%. Average mPAP was 40.5 ± 8.8 mmHg. Low, moderate, and high-mPAP category MAF were similar (χ² = 3.03; P = 0.22), with values of 35.4, 31.0, and 37.8%, respectively. Additionally we sought to evaluate the genotype-to-phenotype association of this SNP with mPAP phenotypes (n = 532) from the Colorado State University Beef Improvement Center (elevation 2150 m) Angus herd. Linear mixed model analysis suggested genotype was not a predictor (P = 0.61) of mPAP. Results do not suggest the A allele of SNP in EPAS1 is associated with high altitude-induced PH in yearling Angus cattle.