Chia (Salvia hispanica), an herbaceous plant native to Latin America, has become important in the last 20 years due to its beneficial effects on health. Here, we present the first record and identification of two viruses in chia plants. The comparison of the complete nucleotide sequences showed the presence of two viral species with the typical genome organization of bipartite New World begomovirus, identified as Sida mosaic Bolivia virus 2 and Tomato yellow spot virus, according to the ICTV taxonomic criteria for begomovirus classification. DNA-A from Sida mosaic Bolivia virus 2 exhibited 96.1% nucleotide identity with a Bolivian isolate of Sida micrantha, and Tomato yellow spot virus showed 95.3% nucleotide identity with an Argentine bean isolate. This is the first report of begomoviruses infecting chia as well as of the occurrence of Sida mosaic Bolivia virus 2 in Argentina.

Since 2018, bacterial-like symptoms, such as leaf streaks were observed on wheat plants (Triticum aestivum L.) in Córdoba province in Argentina, with 1 to 5% of disease incidence. Samples of wheat stem and spike collected in a trial of varieties for summer/autumn sowing in the experimental field of the INTA Marcos Juárez were disinfected, washed and macerated in mortars with sterile distilled water and extracts were streaked on Luria-Bertani (LB) agar. After 48 h incubation at 28 °C, circular, mucoid, convex, and cream colonies were observed and pure cultures were transferred to LB medium for further identification tests. Biochemical tests corroborated the detection of a Gram-negative bacillus. Conventional PCR was performed using DNA isolate from pure cultures and general primers for various species of genera Xanthomonas (Maes 1993) and Pseudomonas (Mulet et al. 2010). An isolate (Arg-1), with cream colored colonies was positive using general primers for Xanthomonas sp (amplified fragment of 444 bp). A bacterial suspension containing 108 CFU mL−1 grown for 48 h on LB medium at 28 °C was injected into three-week-old leaves of wheat plants to fulfill Koch’s postulates. After 5 days, plants showed symptoms of chlorosis, streaks and then necrosis on the leaves. The bacteria were re-isolated from the inoculated plants, showing same symptoms observed in the original plants. Negative control plants, inoculated with sterile water remained without symptoms. The amplified 444 bp fragment described above was sequenced by the Sanger method (GenBank accession OM972662), as well as another 757 bp fragment amplified with universal primers that amplify the partial 16S rDNA gene (GenBank accession OM972661). Analyses of these sequences, as well as the protein profile of the isolate obtained by matrix assisted laser desorption/ionization time of-flight mass spectrometry (MALDI-TOF MS) Bruker Biotyper, allowed to identify only the genus Xanthomonas. With the purpose of determine the species status, the complete genome of isolate Arg-1 was sequenced using Oxford Nanopore Technologies (ONT). Total gDNA was isolate from pure cultures using a commercial kit (Wizard Genomic DNA Purification Kit, Promega). gDNA library was constructed using Ligation Sequencing Kit (SQK-LSK109) and sequenced using ONT platform on a MinION 1kb device. Raw basecalled sequences were filtered using Filtlong and assembled using Trycycler. The genome was assembled in a single contig comprising 5.410.641 bp with 4740 predicted CDSs and 63.9% GC content. Genome sequence was deposited in GenBank under accession number CP094827 and SRA data SRX14635308. Whole-genome Average Nucleotide Identity (ANI) analysis showed values of ~ 97% against the reference genomes of Xanthomonas prunicola (PHKX01.1, PHKV01.1 and PHKW01.1) and 100% in complete 16S rRNA gene sequences (1547 bp). These findings suggest that a new wheat pathogen within the genus Xanthomonas is present in Argentina, as well as was reported in Uruguay and USA (Clavijo et al. 2021). To our knowledge, this is the first report of X. prunicola affecting wheat in Argentina and the first complete genome registered for this specie. Accurate and specific diagnostics are required for the detection of X. prunicola in wheat crops to implement correct prevention and control strategies to this disease, avoiding the dissemination in lots where it has not yet been found.

Sweet potato (Ipomoea batatas (L.) Lam) is one of the most important crops worldwide. Recently, the appearance of severe viral symptoms has been observed in sweet potato crops in the pampas region of Argentina and both begomovirus and crinivirus, exclusively transmitted by whiteflies, have been identified. The aim of this study was to identify B. tabaci species from sweet potato crops in Colonia Caroya by analysing mitochondrial cytochrome c oxidase subunit I (mtCOI) sequences. Two previously described haplotypes were identified: New World2 (indigenous species) and MEAM1 (introduced species). The results indicate the presence of both species, which are potential vectors of begomovirus and crinivirus in Argentina.

Symptomatic sweet potato cv Arapey INIA samples were collected from a commercial production field in Colonia Molina, Guaymallén department, Mendoza province, Argentina. They showed dark rounded lesions, sometimes coalescing with white granular mycelium. Fungus was obtained from symptomatic sweet potatoes, which represented the generalized infection that affected the crop. They were seeded in PDA with streptomycin sulfate and incubated for seven days at 21°C, alternating white/black (UV400nm) light. Observations with an optical microscope revealed the presence of hyaline, not septated, cylindrical endoconidia with rounded ends. They were 8-16 μm length and 4–6 μm width. Phialides were 43-46 μm length, rounded bases (7-9 μm width) and tapering to the neck´s tip (4-6 μm width). Brown chlamydospores (aleuriospores), 9-13 μm length and 8-12 μm width, in chains of 2-8 spores were observed. For molecular identification, total genomic DNA was extracted. ITS fragment of 565 pb was amplified using ITS5/ITS4 primers and sequenced. The sequence indicated 99% identity with Berkeleyomyces basicola (synonymous: Thielaviopsis basicola). This was deposited in GenBank as (KX580957) (CBS: C430.74, Gen Bank accession number AF275482.1). This is the first report of B. basicola in sweet potato in Argentina, a potential threat to storage root yields. Highlights: Sweet potato black root rot, new disease in Argentina. First report of Berkeleyomyces basicola  causing black root rot on sweet potato in Mendoza, Argentina.