Biology subjects

Ali, G.

Publications and source records attributed to Ali, G..

3 recordsLinked to original sources

bioRxiv2019

Overexpression of the Arabidopsis thaumatin-like protein 1 in transgenic potato plants enhances resistance against early and late blights

The Arabidopsis thaumatin-like protein 1 (ATLP1), which belongs to the PR5 family of pathogenesis-related proteins, is induced by pathogen attacks and by systemic acquired resistance (SAR)-inducing compounds. To test whether the overexpression of ATLP1 will enhance fungal resistance in transgenic plants, the cDNA of this gene under the control of a constitutive promoter was transferred into Solanum tuberosum Cv. Desiree. The expression of the introduced gene was confirmed by Northern and Western blot analyses. Western blot analysis performed with intercellular fluid (ICF) showed that ATLP1 is secreted to apoplast. Several independent transgenic lines with high-level expression of the ATLP1 were assayed for resistance against early blight (Alternaria solani) and late blight (Phytophthora infestans). The rate of Alternaria lesions development was significantly reduced in the ATLP1 transgenic lines as compared to a control line. Percent reductions in area under the disease progress curve (AUDPC) values for the ATLP1 transgenic lines as compared to control line ranged between 52 and 82%. In response to P. infestans, infection efficiency (IE), lesion size (LS) and sporulation capacity (SC) were significantly reduced in ATLP1 transgenic lines as compared to a control line. On the average, IE, LS and SC were reduced by 18, 22 and 20%, respectively, for all transgenic lines with a maximum reduction of 25% in IE, 25% in LS and 32% in SC. Resistance assays against P. infestans using whole plants showed 40-70% reduction in symptoms as compared to control. These results suggest that constitutive expression of a heterologous ATLP in potato confers enhanced resistance against early and late blights.

plant biology↗

bioRxiv2019

Transcriptional profiling of Impatiens walleriana genes through different stages of downy mildew infection reveals novel genes involved in disease susceptibility

Impatiens downy mildew is a highly destructive disease of Impatiens walleriana, and economically important bedding ornamental crop. This disease is caused by a recently emerged pathogen Plasmopara obducens. Since both the host and pathogen are relatively less studied, there are only a few genomic resources available for both I. walleriana and P. obducens. In this study, we have analyzed transcriptional changes in I. walleriana in response to P. obducens infection during different stages of disease development. Our main goal was to identify candidate genes that may be involved in I. walleriana susceptibility to P. obducens. Since the genome of I. walleriana is not available publicly, we constructed and optimized a de novo transcriptome assembly consisting of 73,022 transcripts. Differential expression analysis based on this optimized de novo transcriptome assembly revealed 3,000 to 4,500 differentially expressed transcripts (DETs) at 0 hr, 12 hr, 48 hr, 120 hr, and 240 hr time points after infection. Functional annotation of these DETs revealed that numerous plant stress responsive genes are activated and deactivated throughout the infection cycle. Genes in the calcium signaling pathways, receptor-like kinases (RLKs) including 10 disease resistance associated RLK transcripts, powdery mildew resistance genes (MLO), and many other plant stress related genes were predominantly differentially expressed in I. walleriana in response to P. obducens. Analyses reported here provides molecular insights into the disease susceptibility mechanism of the Impatiens downy mildew, and lays out a strong foundation for future studies aimed at improving downy mildew resistance in I. walleriana.

plant biology↗

bioRxiv2019

Bioactivity-driven high throughput screening of microbiomes of medicinal plants for discovering new biological control agents

In a preliminary DNA-based microbiome studies, diverse culturable and unculturable bacterial taxa were identified in the roots and rhizospheres of different medicinal plants. In this report, culturable endophytic bacteria were isolated from four economically important medicinal plants Dodonaea viscosa, Fagonia indica, Caralluma tuberculata and Calendula arvensis. On the basis of initial antimicrobial screening, nine bacterial species in seven different genera, Streptomyces, Pseudomonas, Enterobacter, Bacillus, Pantoea, Pseudarthrobacter and Delftia, were selected for further analyses. These bacteria were identified using 16S rRNA gene sequencing. Antimicrobial assays of these selected bacteria revealed that Pseudomonas taiwanensis has strong anti-Phytophthora activity. Volatiles produced by P. taiwanensis inhibited growth of P. parasitica more than 80%. Ethyl acetate extracts of S. alboniger MOSEL-RD3, P. taiwanensis MOSEL-RD23, E. hormaechei MOSEL-FLS1 and B. tequilensis MOSEL-FLS3 and D. lacustris MB322 also displayed high potency against P. parasitica. All these bacterial extracts showed strong inhibition against P. parasitica at different concentrations (4 {micro}g/mL - 400 {micro}g/mL). Bacterial extracts showing higher bioactivity (>80% inhibition in vitro) were selected for detached-leaf assay against P. parasitica on tobacco. In detached-leaf assay, application of 1% ethyl acetate bacterial extract of MOSE L-RD3, MOSEL-RD23, MOSEL-FLS1, MOSEL-FLS3 and MB322 reduced lesion sizes and lesion frequencies caused by P. parasitica by 68 to 81%. Over all P. taiwenensis MOSEL-RD23 showed positive activities for all the assays. Analysing the potential of bacterial endophytes as biological control agents can potentially lead to the formulation of broad-spectrum biopesticides for sustainable production of crops.

microbiology↗