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Cassava (Manihot esculenta Crantz) was introduced to Southeast Asia in the 16th–17th centuries and has since flourished as an industrial crop. Since the 1980s, Thailand has emerged as the leading producer and exporter of cassava products. This growth coincided with the initiation of cassava breeding programs in collaboration with the International Center for Tropical Agriculture (CIAT), focusing on root yield and starch production. The success of Thai cassava breeding programs can be attributed to the incorporation of valuable genetic diversity from international germplasm resources to cross with the local landraces, which has become the genetic foundation of many Thai commercial varieties. Effective evaluation under diverse environmental conditions has led to the release of varieties with high yield stability. A notable success is the development of Kasetsart 50. However, extreme climate change poses significant challenges, including abiotic and biotic stresses that threaten cassava root yield and starch content, leading to a potential decline in starch-based industries. Future directions for cassava breeding must include hybrid development, marker-assisted recurrent breeding, and gene editing, along with high-throughput phenotyping and flower induction. These strategies are essential to achieve breeding objectives focused on drought tolerance and disease resistance, especially for CMD and CBSD. [ABSTRACT FROM AUTHOR]

Cassava mosaic disease (CMD) is a major disease affecting cassava production in Southeast Asia. This study aimed to perform an integrated proteomics and metabolomics analysis of cassava cv. Kasetsart 50 infected with Sri Lankan cassava mosaic virus (SLCMV). Proteomics analyses revealed that 359 proteins were enriched in the plant–pathogen interaction, plant hormone signal transduction, and MAPK signaling pathways. A total of 79 compounds were identified by metabolomics analysis of the healthy and SLCMV-infected cassava plants. Integrated omics analysis revealed that 9 proteins and 5 metabolites were enriched in 11 KEGG pathways. The metabolic pathways, plant hormone signal transduction, and plant–pathogen interaction pathway terms were specifically investigated. The findings revealed that caffeic acid and chlorogenic acid were associated with the plant–pathogen interaction pathway, histidine (HK3) was involved in plant hormone signal transduction, while citric acid and D-serine were associated with the metabolic pathways. KEGG functional enrichment analysis revealed that plant–pathogen interaction, plant hormone signal transduction, and metabolic pathways were linked via the enriched protein (protein phosphatase 2C) and metabolites (cyclic nucleotide-binding (AT2G20050) and D-serine). The available information and resources for proteomics and metabolomics analyses of cassava can elucidate the mechanism of disease resistance and aid in cassava crop improvement programs. [ABSTRACT FROM AUTHOR]

Papaya ringspot virus (PRSV) causes the Papaya ringspot disease. Virus–host interactions appear to play a significant role in the replication, pathogenesis, and infection caused by the PRSV. PRSV coat protein is likely to be involved in the processes of RNA replication, aphid transmission, and cell-to-cell movement, which is closely related to the host cell proteins resulting in a PRSV infection. To identify the host proteins that interact with the CP in vitro, immune precipitation, in-solution trypsin digestion, and LC–MS/MS were performed. Twenty-three identified proteins that interacted with the CP are involved in cellular metabolism, transcription, signal, translation, carbohydrate metabolism, protein metabolism, stress response, photosynthesis, nucleotide metabolism, respiration, and lipid metabolism processes. The search tool for interactions of chemicals (STITCH) results show that SWP (an RNA polymerase II transcription mediator) and MPPBETA (Mitochondrial processing peptidase) are involved in known plant defense mechanisms including transcription factors, cell division, hormones, stress, mitochondrial electron transferase, respiration, and proteasome. Therefore, analyzing virus–host protein interactions at a molecular level is important to build a better understanding of the virus replication mechanism and cellular responses mounted against viruses by the host defense system. [ABSTRACT FROM AUTHOR]

Cassava plantations in an area of 458 hectares spanning five provinces along the Thailand–Cambodia border were surveyed from October 2018 to July 2019 to determine the prevalence of cassava mosaic disease (CMD) caused by Sri Lankan cassava mosaic virus (SLCMV) in the region. CMD prevalence was 40% in the whole area and 80% in Prachinburi, 43% in Sakaeo, 37% in Burium, 25% in Surin, and 19% in Sisaket provinces. Disease incidence of CMD was highest 43.08% in Sakaeo, followed by 26.78% in Prachinburi, 7% in Burium, 2.58% in Surin, and 1.25% in Sisaket provinces. Disease severity of CMD symptoms was mild chlorosis to moderate mosaic (2–3). The greatest disease severity was recorded in Prachinburi and Sakaeo provinces. Asymptomatic plants were identified in Surin (12%), Prachinburi (5%), Sakaeo (0.2%), and Buriram (0.1%) by PCR analysis. Cassava cultivars CMR-89 and Huai Bong 80 were susceptible to CMD. In 95% of cases, the infection was transmitted by whiteflies (Bemisia tabaci), which were abundant in Sakaeo, Buriram, and Prachinburi but were sparse in Surin; their densities were highest in May and June 2019. Nucleotide sequencing of the mitochondrial cytochrome oxidase 1 (mtCO1) gene of whiteflies in Thailand revealed that it was similar to the mtCO1 gene of Asia II 1 whitefly. Furthermore, the AV1 gene of SLCMV—which encodes the capsid protein—showed 90% nucleotide identity with SLCMV. Phylogenetic analysis of completed nucleotide sequences of DNA-A and DNA-B components of the SLCMV genome determined by rolling circle amplification (RCA) indicated that they were similar to the nucleotide sequence of SLCMV isolates from Thailand, Vietnam, and Cambodia. These results provide important insights into the distribution, impact, and spread of CMD and SLCMV in Thailand. [ABSTRACT FROM AUTHOR]

Sri Lankan cassava mosaic virus (SLCMV) poses a significant threat to global food security by affecting the production of cassava (Manihot esculenta) in South‐east Asia. It causes mosaic patterns on the leaves, disrupts photosynthesis and respiration, and alters carbohydrate accumulation in the tubers. This study aimed to identify proteins associated with cassava mosaic disease symptoms in three cassava cultivars: resistant (TMEB419), tolerant (Kasetsart 50, KU50) and susceptible (Rayong 11, R11) to SLCMV. These cultivars were inoculated with SLCMV using top‐cleft grafting and monitored at 21, 32 and 67 days post‐inoculation (dpi). The disease severity differed among the cultivars following SLCMV inoculation. Liquid chromatography–tandem mass spectrometry (LC–MS/MS)‐based proteomics analysis identified 541 differentially expressed proteins (DEPs), including photosynthesis‐ and respiration‐associated proteins such as RuBisCO large subunit‐binding protein α (LSBP), chlorophyll a‐b binding protein, photosystem I reaction centre subunit III (PSI‐F), glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and fructose‐bisphosphate aldolase (FBA). A protein–protein interaction network revealed interactions among PSI, PSII, cytochrome complex proteins and electron transporter proteins. Chlorophyll(ide) b reductase NYC1, upregulated in R11 (susceptible) at 21 and 32 dpi, interacted with chlorophyllase‐related proteins, suggesting that it has a role in altering chlorophyll metabolism. Reverse transcription‐quantitative PCR gene expression analysis confirmed upregulation of genes related to photosynthesis and respiration in KU50 and R11, predominantly at 21 or 32 dpi. These findings provide valuable insights into cassava responses to SLCMV infection, especially at the protein level and are key for developing resistant cultivars and effective disease management strategies in future research. [ABSTRACT FROM AUTHOR]

Sri Lankan cassava mosaic virus is an emerging pathogen in Southeast Asia. Here, we report the complete genome of a Thai isolate obtained using Nanopore technology. The isolate was collected in 2019 from the northeastern province of Surin, soon after disease eradication was reported in the country., (Copyright © 2020 Leiva et al.)