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Biology subjects

Lelwala, R. V.

Publications and source records attributed to Lelwala, R. V..

2 recordsLinked to original sources

The Development of Wet Laboratory Methods for Improved Downstream Analysis of High Throughput Sequencing Data for Virus and Viroid Diagnostics of Vitis vinifera in Australian Post-Entry Quarantine

High throughput sequencing (HTS) methods are an essential tool in Australias Post-Entry Quarantine (PEQ) facility to facilitate the rapid, reliable and sensitive diagnostics of plant viruses and viroids. Small RNA sequencing (sRNAseq) for the detection of viruses and viroids has been implemented for several plant commodities in PEQ, including clonal grasses, Prunus spp., Rubus spp., and Fragaria spp., with the potential to expand to further plant genera. Currently, imported grapevine (Vitis spp.) require many PCR assays (22) which are both laborious and time consuming. In this study we compare different wet laboratory processes for Vitis vinifera ribonucleic acid (RNA) extraction, including different tissue types, tissue weights and elution volumes and their effects on detecting viruses and viroids by Illumina sRNA sequencing. Overall, our results suggest that increased RNA concentration of V. vinifera can be achieved by using cambium tissue, reducing elution volume and decreasing the tissue weight. Furthermore, when comparing sRNAseq to current PCR methods in post-entry quarantine, sRNAseq outperformed the prescribed PCRs.

molecular biology↗

Comparative genome analysis indicates rapid evolution of pathogenicity genes in Colletotrichum tanaceti

Colletotrichum tanaceti is an emerging foliar fungal pathogen of pyrethrum (Tanacetum cinerariifolium), posing a threat to the global pyrethrum industry. Despite being reported consistently from field surveys in Australia, the molecular basis of pathogenicity of C. tanaceti on pyrethrum is unknown. Herein, the genome of C. tanaceti (isolate BRIP57314) was assembled de novo and annotated using transcriptomic evidence. The inferred pathogenicity gene suite of C. tanaceti comprised a large array of genes encoding secreted effectors, proteases, CAZymes and secondary metabolites. Comparative analysis of its CAZyme pathogenicity profiles with those of closely related species suggested that C. tanaceti had additional hosts to pyrethrum. The genome of C. tanaceti had a high repeat content and repetitive elements were located significantly closer to genes inferred to influence pathogenicity than other genes. These repeats are likely to have accelerated mutational and transposition rates in the genome, resulting in a rapid evolution of certain CAZyme families in this species. The C. tanaceti genome consisted of a gene-sparse, A-T rich region facilitating a "two-speed" genome. Pathogenicity genes within this region were likely to have a higher evolutionary rate than the core genome. This "two-speed" genome phenomenon in certain Colletotrichum spp. was hypothesized to have caused the clustering of species based on the pathogenicity genes, to deviate from taxonomy. With the large repertoire of pathogenicity factors that can potentially evolve rapidly in response to control measures, C. tanaceti may pose a high-risk to global pyrethrum production. Knowledge of the pathogenicity genes will facilitate future research in disease management of C. tanaceti and other Colletotrichum spp..

genomics↗