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Biology subjects

Ashworth, V. E. T. M.

Publications and source records attributed to Ashworth, V. E. T. M..

2 recordsLinked to original sources

Insights into the domestication of avocado and potential genetic contributors to heterodichogamy

O_LIThe domestication history of avocado (Persea americana) remains unclear, in part due to a lack of suitable genomic tools. C_LIO_LIWe created a reference genome from the Gwen varietal, which is closely related to the economically dominant Hass varietal. We also compiled a database of 34 resequenced accessions that represented the three botanical races of P. americana. C_LIO_LIOur genome assembly had an N50 of 3.37 megabases, a BUSCO score of 91% and was scaffolded with a genetic map, producing 12 pseudo-chromosomes with 49,450 genes. We used the Gwen genome as a reference to investigate the population genomics of avocado. Our analyses were consistent with three separate domestication events; we estimated that the Mexican race diverged from the Lowland (formerly known as West Indian) and Guatemalan races >1 million years ago. We also identified putative targets of selective sweeps in domestication events; within the Guatemalan race, putative candidate genes were enriched for fruit development and ripening. We also investigated divergence between heterodichogamous flowering types. C_LIO_LIWith the help of a new reference genome, we inferred the domestication history of avocado and identified genes that may contribute to heterodichogamy, including genes with functions in pollination and floral development. C_LI

genomics↗

Arbuscular mycorrhizal fungal composition across US citrus orchards, management strategies, and disease severity spectrum

Arbuscular mycorrhizal fungi (AMF) remain understudied in perennial cropping systems. Citrus is a globally grown fruit tree and under threat by the pandemic Huanglongbing (HLB) disease. Here, we assessed in what capacity geographical location, management strategies and disease affect AMF citrus root communities. Root samples were collected from 88 trees in ten orchards located in the two major citrus producing states in the US. Orchards were selected based on conventional or organic practices in California and based on HLB symptom severity in Florida. We used AMF-specific amplicon sequencing primers to capture community composition and diversity. Taxa names were assigned based on a phylogenetic analysis that comprised a backbone of AMF references sequences from Mycobank and virtual taxa from the MaarjAM database. AMF were detected in 78% of citrus root samples with taxa belonging to six known (Dominikia, Funneliformis, Glomus, Rhizophagus, Sclerocystis, Septoglomus) and unknown Glomeraceae genera. Geographical location affected AMF community composition but not richness, whereas management practice and disease influenced both richness and composition. Our approach indicated that perennial agroecosystems share a set of AMF generalist and specialist taxa. Some taxa could improve environmental fitness and be exploited for agricultural purposes.

microbiology↗