Acheampong, S. | Search bioRxiv

bioRxiv2022

Diversity, Phylogenetic Relationships, And Expression Profiles Of Invertase Inhibitor Genes In Sweetpotato

Invertases and their inhibitor proteins are key regulators of carbon allocation in plants. Manipulation of invertase inhibitor (ITI) activity can potentially increase crop yield. The aim of this study was to determine the sequence diversity, phylogenetic relationships, and expression profiles of ITI genes in sweetpotato(Ipomoea batatas).. The coding sequences of two ITI paralogs (SPITI1 and SPITI2) were cloned from two sweetpotato varieties (Beauregard and Jewel) and sequenced. The DNA sequences were used to deduce amino acids sequences and predicted protein properties. Quantitative PCR (qPCR) was carried out to study the expression profiles of the genes at different developmental stages. The results show that introns are absent in both SPITI paralogs. SNPs, Indels, and variable simple sequence repeats (SSR) were present in the SPITI1 paralog, however, only SNPs were identified in the SPITI2 paralog. The predicted SPITI1 protein had 168, 172, or 174 amino acid residues, and molecular weights ranging from 17.88 to 18.38 kDa. In contrast, SPITI2 coded for a protein with 192 amino acid residues, with molecular weight ranging from 20.59 to 20.65 kDa. All conserved domains of ITI proteins were present in both protein isoforms. Phylogenetic analysis indicated that SPITI genes were more closely related to I.trifida and I.triloba than I.nil, thus, suggesting their evolutionary relationship and conservation. A qPCR study indicated that both SPITI genes were expressed in all the sample tissues, though relative expression values differed across tissues at different developmental stages. This is the first study reporting diversity of SPITI genes and of an ~18 kDA isoform in sweetpotato. The findings may enable design of genetic engineering strategies for SPITI genes, including CRISPR/Cas gene editing in sweetpotato.

molecular biology↗

bioRxiv2021

Adventive larval parasitoids reconstruct their close association with spotted-wing drosophila in the invaded North American range

Two species of larval parasitoids of the globally invasive fruit pest, Drosophila suzukii (Diptera: Drosophilidae), Leptopilina japonica and Ganaspis brasiliensis (both Hymenoptera: Figitidae), were detected in British Columbia, Canada in 2019. Both are presumed to have been unintentionally introduced from Asia, however; the extent of their establishment across different habitats with diverse host plants used by D. suzukii was unclear. In addition, there was no knowledge of the temporal dynamics of parasitism of D. suzukii by these two parasitoids. We repeatedly sampled the fruits of known host plants of D. suzukii over the entire 2020 growing season in British Columbia. We documented the presence of L. japonica and G. brasiliensis and estimated the apparent percentage of D. suzukii parasitized. Across a large region of southwestern British Columbia, both L. japonica and G. brasiliensis were found to be very common across a variety of mostly unmanaged habitats over the entire course of the season (May-October) in the fruits of most host plants known to host D. suzukii larvae. The two parasitoids were responsible for more than 98% of D. suzukii larval parasitism and usually co-existed. Parasitism of D. suzukii was variable among hosts plants and sites (0-66% percent parasitism) and appeared to be time-structured. Our study demonstrates that the close association between the two larval parasitoids and D. suzukii that exists in Asia has evidently been reconstructed in North America, resulting in the highest parasitism levels of D. suzukii yet recorded outside of its area of origin.

ecology↗