Starchy Root Crop Research Articles

Cassava breeding: Classical to recent breeding approaches for food, industry and climate resilience

Cassava ranks as the fourth-most significant starchy root crop in underdeveloped countries in terms of future food and acting as a key source of income for small and marginal farmers. To meet the growing demands for food security and economic development, it is imperative to develop improved cassava varieties that offer higher yields, enhanced nutritional content, safer for consumption, greater resistance to diseases and climate change. The development of these improved varieties necessitates advancements in breeding techniques, leveraging both traditional methods and modern biotechnological tools. However, a major challenge in cassava breeding is heterozygous nature and the crop’s sparse flowering, which limits the potential for sexual reproduction, thereby constraining breeding efforts for predominantly clonal selection. The continuous clonal propagation impedes genetic diversity and the introduction of novel traits, narrowing the overall progress of breeding programs. Integrating genomic tools and accelerating the adoption of biotechnological advancements can overcome these limitations and expedite the development of superior cassava varieties. This review highlights the need of cassava breeding for addressing these challenges with conventional as well as with new breeding techniques with the aim to provide a comprehensive understanding of the current scenario and future directions of cassava breeding research. Key words: Climate change, CRISPR/Cas 9, New breeding techniques, PPD, speed breeding, Waxy cassava

Elucidation of novel drought-responsive genes from tuber transcriptome of cassava under water deficit stress

Cassava (Manihot esculenta Carntz) is the major starchy root crop grown in the tropical parts of the world. Two cassava clones contrasting for their drought tolerance capacity (8S501- drought tolerant and H97-drought sensitive) were selected and grown in the field for studying the agronomical and molecular changes in both the clones under drought stress conditions. A reduction in the number of tuberous roots per plant, tuberous root length, average single tuber weight and tuber yield per plant was observed under drought stress when compared with the control conditions and also significantly lower mean values were observed for the sensitive clone H97 than that of the tolerant clone 8S501 when measured at 60 days of stress. Transcriptome sequencing of the tuber tissues of the two clones was done at 60 days of imposing drought stress. Different genes belonging to various groups like aquaporins, transporter genes, growth regulator related genes, calcium binding and mineral transfer-related genes, transferase genes and transcription factors were differentially expressed in the tubers under drought stress. Comparative transcriptomics revealed that acyl-CoA oxidase, primary-amine oxidase, glutathione peroxidase, vesicle transport, late embryogenesis abundant protein related, histone demethylase, BR-signaling kinase, palmitoyltransferase, DNA mismatch repair protein, heat shock protein related, starch/sucrose metabolic pathway related and MFS transporter genes were differentially expressed in the tubers of the tolerant clone 8S501 relative to the susceptible clone H97.

Evaluating non-photochemical quenching (NPQ) kinetics and photosynthetic efficiency in cassava (Manihot esculenta) subjected to variable high light conditions.

Light intensity is a critical environmental factor influencing plant growth and development. To survive high light conditions, plants have evolved various protective mechanisms, including non-photochemical quenching (NPQ). However, NPQ can limit effective photosynthetic yield when transitioning to low light conditions. This phenomenon is underexplored in cassava (Manihot esculenta ), a starchy storage root crop known for its high biological efficiency and climate resilience. To address this knowledge gap, we assessed the photoprotective abilities and growth responses of six cassava varieties under natural environmental light conditions (control) and intermittent high light (IHL) conditions by adding 900μmolm-2 s-1 using full-spectrum LED lights, on top of the natural ambient daylight. Our results demonstrated a significant impact of light treatment on aboveground biomass, total crop biomass, chlorophyll a and b content, photosynthetic rate, and NPQ values during transitions from low to high light and vice versa. Notably, cassava variety 'Sree Suvarna' exhibited the highest yield under both control and IHL conditions. These findings suggest that screening cassava varieties for their ability to postpone photoinhibition and recover quickly from photoinhibition may enhance photosynthetic performance. Such strategies have important implications for improving the efficiency and resilience of cassava crops, ultimately contributing to sustainable agricultural productivity.

Synthesis of Cassava Starch Biofilm with the Addition of Extract of Couroupita guianensis fruit by Casting Method

Brazil is now the world's fourth-largest banana producer in the world with an annual production of 6.953,747 tons per year. In Brazil, the banana (Musa spp.) stands out, not only because it is the most widespread, but also because it is the most consumed by all social classes. Cassava is a renewable, almost unlimited resource and one of the most abundant substances in nature. It is one of the most important starchy root crops of the tropics used for food and industrial purposes. The present study evaluated the use of biofilms based on cassava starch in maintaining the quality and shelf life of the 'Prata' banana at room temperature. The filmogenic solution was created using the casting technique, with adaptations. Additionally, 2.6% cassava starch (m/v) + 2 g of gelatin + 100 mL of the aqueous extract were used. Additionally, the biofilm was applied in the film-forming solution for 1 minute and suspended for further drying at room temperature. After this process, were evaluated the loss of fresh mass, and total soluble solids. The present study revealed the efficiency of biofilm coating with and without gelatin to reduce the rate of enzymatic browning and increase the shelf life of bananas. It was possible to verify a smaller reduction in fresh weight loss in the treatments. Besides, no significant difference was observed in the addition of gelatin to the parameters evaluated in the fruit.

CRISPR-Cas9-mediated knockout of CYP79D1 and CYP79D2 in cassava attenuates toxic cyanogen production.

Cassava (Manihot esculenta) is a starchy root crop that supports over a billion people in tropical and subtropical regions of the world. This staple, however, produces the neurotoxin cyanide and requires processing for safe consumption. Excessive consumption of insufficiently processed cassava, in combination with protein-poor diets, can have neurodegenerative impacts. This problem is further exacerbated by drought conditions which increase this toxin in the plant. To reduce cyanide levels in cassava, we used CRISPR-mediated mutagenesis to disrupt the cytochrome P450 genes CYP79D1 and CYP79D2 whose protein products catalyze the first step in cyanogenic glucoside biosynthesis. Knockout of both genes eliminated cyanide in leaves and storage roots of cassava accession 60444; the West African, farmer-preferred cultivar TME 419; and the improved variety TMS 91/02324. Although knockout of CYP79D2 alone resulted in significant reduction of cyanide, mutagenesis of CYP79D1 did not, indicating these paralogs have diverged in their function. The congruence of results across accessions indicates that our approach could readily be extended to other preferred or improved cultivars. This work demonstrates cassava genome editing for enhanced food safety and reduced processing burden, against the backdrop of a changing climate.

On-Farm Multi-Environment Evaluation of Selected Cassava (Manihot esculenta Crantz) Cultivars in South Africa.

Cassava is an important starchy root crop grown globally in tropical and subtropical regions. The ability of cassava to withstand difficult growing conditions and long-term storability underground makes it a resilient crop, contributing to food and nutrient security. This study was conducted to evaluate the performance and adaptability of exotic cassava cultivars across different environments in South Africa and to recommend genotypes for cultivation. A total of 11 cassava cultivars were evaluated at six on-farm sites, using a randomized complete block design with three replications. There were highly significant (p < 0.001) variations between genotypes, environments, and their interaction for all yield and yield-related traits studied. This indicates the need to test the genotypes in multiple environments before effective selection and commercialization can be undertaken. MSAF2 and UKF4 showed the overall best performances for most of the traits, whilst UKF9 (49.5%) and P1/19 (48.5%) had the highest dry matter yield. UKF4 (102.7 t ha−1) had the highest yield and greatest root yield stability across environments. MSAF2 did not perform consistently across environments because it was highly susceptible to cassava mosaic disease (CMD). MSAF2 could be used as a donor parent to generate novel clones with large numbers of marketable roots, and high fresh root yields, if the other parent can provide effective resistance to CMD. Based on genotype and environmental mean, Mabuyeni (KwaZulu-Natal), Mandlakazi (Limpopo), and Shatale (Mpumalanga) were found to be better environments for cassava cultivation and testing. This study is a pioneer in cassava research using multiple environments in South Africa. It provides baseline information on the performance of currently available cassava clones, their adaptation to multiple sites, the identification of suitable test sites, and information on current genetic resources for a future breeding program.

Effect of cassava starch biofilm with diffusion of silver nanoparticles on the conservation of banana 'prata'

Brazil is now the world's fourth-largest banana producer in the world with an annual production of 6.953,747 tons per year. In Brazil, the banana (Musa spp.) stands out, not only because it is the most widespread, but also because it is the most consumed by all social classes. Cassava is a renewable, almost unlimited resource and one of the most abundant substances in nature. It is one of the most important starchy root crops of the tropics used for food and industrial purposes. The present study aimed to evaluate the use of biofilms based on cassava starch with the diffusion of silver nanoparticles (AgNP) on the conservation of banana 'Prata'. Initially, filmogenic solutions were produced using the casting technique for five treatments. Additionally, transparency, thickness, grammage, and, subsequently, the biofilms were applied in the film-forming solution for 1 min and suspended for further drying at room temperature. After this process, were evaluated the fresh mass loss and total soluble solids. This study revealed the efficiency of cassava starch biofilm with gelatin addition to reduce the enzymatic browning rate and increase the shelf life of bananas (Musa Subgroup Prata). However, no significant results were observed with the addition of commercial silver nanoparticles .

Use of Diversity Arrays Technology (DArT) for detection of QTL underlying plant architecture and yield-related traits in cassava

ABSTRACT Cassava (Manihot esculenta Crantz) is an important starchy root crop representing food security for more than one billion people in the world. Plant architecture (PA) is a key factor underlying yield, and understanding the physiological basis of PA may lead to improved yield plants. In this study, we identified genomic regions controlling several traits associated with plant architecture and productivity in Thai cassava cultivars. The analysis was conducted in an F1 population derived from a cross between “Huay Bong 60” (female parent) and “Hanatee” (male parent). A genetic linkage analysis was undertaken with 167 conventional DArT markers using JoinMap 3.0 software. Plant architecture and productivity were evaluated over four years at the Rayong Field Crops Research Center, Thailand. DArT markers associated with five traits of plant architecture (number of mainstems per plant (NMain), number of apices per plant (NAp), plant height (PH), first branching height (BH), branching level (BL)) as well as two productivity measurements harvest index (HI) and fresh root yield (FRY) were identified by simple interval mapping (SIM) using MapQTL 4.0. Small effects of 22 plant architecture quantitative trait loci (QTL) were detected, with phenotypic contributions varying from 5.1 to 10.9%. Small effects of four QTL of FRY and five QTL of HI were also detected. Additionally, PH showed a significant correlation with FRY. However, this study has limitations from the low density of the markers, therefore additional markers would be necessary for an efficient genetic linkage map and QTL detection.

Low‐cost, handheld near‐infrared spectroscopy for root dry matter content prediction in cassava

AbstractOver 800 million people across the tropics rely on cassava (Manihot esculenta Crantz) as a major source of calories. While the root dry matter content (RDMC) of this starchy root crop is important for both producers and consumers, characterization of RDMC by traditional methods is time‐consuming and laborious for breeding programs. Alternate phenotyping methods have been proposed but lack the accuracy, cost, or speed ultimately needed for cassava breeding programs. For this reason, we investigated the use of a low‐cost, handheld near‐infrared spectrometer (740–1070 nm) for field‐based RDMC prediction in cassava. Oven‐dried measurements of RDMC were paired with 21,044 scans of roots of 376 diverse genotypes from 10 field trials in Nigeria and grouped into training and test sets based on cross‐validation schemes relevant to plant breeding programs. Mean partial least squares regression model performance ranged from R2P = 0.62–0.89 for within‐trial predictions, which is within the range achieved with laboratory‐grade spectrometers in previous studies. Relative to other factors, model performance was highly affected by the inclusion of samples from the same environment in both the training and test sets. With appropriate model calibration, the tested spectrometer will allow for field‐based collection of spectral data with a smartphone for accurate RDMC prediction and potentially other quality traits, a step that could be easily integrated into existing harvesting workflows of cassava breeding programs.

Assessment of cassava starch biofilm in the quality and shelf life of banana 'prata'

Brazil is now the world's fourth-largest banana producer in the world with an annual production of 6.953,747 tons per year. In Brazil, the banana ( Musa spp.) stands out, not only because it is the most widespread, but also because it is the most consumed by all social classes. Cassava is a renewable, almost unlimited resource and one of the most abundant substances in nature. It is one of the most important starchy root crops of the tropics used for food and industrial purposes. The present study evaluated the use of biofilms based on cassava starch in maintaining the quality and shelf life of the 'Prata' banana at room temperature. Initially, filmogenic solutions were produced using the casting technique for two treatments. T1 (2.6% starch / 500 mL of distilled water); T2 (2.6% starch / 500 mL of distilled water + 1 g of gelatin). Additionally, thickness, weight, and, subsequently, the biofilms were applied in the film-forming solution for 1 min and suspended for further drying at room temperature. After this process, were evaluated the loss of fresh mass, pH, and totals soluble solids. The present study revealed the efficiency of biofilm coating with and without gelatin to reduce the rate of enzymatic browning and increase the shelf life of bananas. It was possible to verify a smaller reduction in fresh weight loss in the treatments. Besides, no significant difference was observed in the addition of gelatin to the parameters evaluated in the fruit.

Suppressed expression of starch branching enzyme 1 and 2 increases resistant starch and amylose content and modifies amylopectin structure in cassava.

Suppression of starch branching enzymes 1 and 2 in cassava leads to increased resistant starch content through the production of high-amylose and modification of the amylopectin structure. Cassava (Manihot esculenta Crantz) is a starchy root crop used for human consumption as a staple food and industrial applications. Starch is synthesized by various isoforms of several enzymes. However, the function of starch branching enzymes (SBEs) in starch biosynthesis and mechanisms of starch regulation in cassava have not been understood well. In this study, we aimed to suppress the expression of SBEs in cassava to generate starches with a range of distinct properties, in addition to verifying the functional characteristics of the SBEs. One SBE1, two SBE2, and one SBE3 genes were classified by phylogenetic analysis and amino acid alignment. Quantitative real-time RT-PCR revealed tissue-specific expression of SBE genes in the tuberous roots and leaves of cassava. We introduced RNAi constructs containing fragments of SBE1, SBE2, or both genes into cassava by Agrobacterium-mediated transformation, and assessed enzymatic activity of SBE using tuberous roots and leaves from these transgenic plants. Simultaneous suppression of SBE1 and SBE2 rendered an extreme starch phenotype compared to suppression of SBE2 alone. Degree of polymerization of 6-13 chains in amylopectin was markedly reduced by suppression of both SBE1 and SBE2 in comparison to the SBE2 suppression; however, no change in chain-length profiles was observed in the SBE1 suppression alone. The role of SBE1 and SBE2 may have functional overlap in the storage tissue of cassava. Simultaneous suppression of SBE1 and SBE2 resulted in highly resistant starch with increased apparent amylose content compared to suppression of SBE2 alone. This study provides valuable information for understanding starch biosynthesis and suggests targets for altering starch quality.

Nutritional, Physicochemical, and Functional Properties of Five Varieties of Taro (Colocasia esculenta)

Abstract Objectives Taro (Colocasia esculenta) is a starchy root crop and a major food source for individuals across Pacific Islands, Asia, and Africa. As a gluten free, hypoallergenic crop with high digestibility, taro may serve as a dietary carbohydrate alternative for food production that adds nutrient value and potential health implications. Thus, this study aimed to explore the nutritional, physicochemical and functional properties of different taro varieties grown in Hawaii. Methods Five varieties of taro (Bun-long, Mana Ulu, Moi, Kauai Lehua, and Tahitian) grown in Hawaii were harvested and processed immediately. The nutritional, physicochemical, and functional properties were analyzed and compared. Results Among the five taro varieties, Moi had the highest concentrations of potassium, copper, and manganese at 1.75 g/100 g, 0.97 mg/100 g, and 12.46 mg/100 g, respectively. Tahitian exhibited the highest concentrations of iron and zinc at 7.74 mg/100 g and 13.68 mg/100 g, respectively. Tahitian, Bun-long, and Moi showed high total starch content of 40.8 g/100g, 38.9 g/100g, and 34.1 g/100g, respectively. Tahitian exhibited the highest water absorption capacity (WAC), oil absorption capacity (OAC), and water solubility index (WSI) at 3.48 g/g, 3.15 g/g, and 33.30 g/100g, respectively. Total starch content of taro was significantly correlated with its WAC, OAC, emulsifying activity, water absorption index, and WSI. Conclusions These results indicate that the taro varieties can be utilized as a carbohydrate alternative for different food processing requirements based on their physicochemical and functional properties to improve nutritional value, food quality and human health. Funding Sources USDA-NIFA Hatch, USDA-ARS.

Large-scale RNAseq analysis reveals new insights into the key genes and regulatory networks of anthocyanin biosynthesis during development and stress in cassava

Anthocyanins play key roles in plant development and response to various biotic and abiotic stresses including drought, cold, and pathogens. However, the key genes and regulatory networks relevant to anthocyanin biosynthesis remain largely elusive in cassava (Manihot esculenta L.), an important starchy root crop in tropical and sub-tropical regions. In this study, 465 RNAseq data were gathered to construct gene coexpression networks in cassava, resulting in a total of 30 coexpression modules (M1-M30). The associations of module-tissue or module-stress/development were systematically analyzed. Meanwhile, the hub genes and molecular roles were extensively dissected for each module, respectively. Notably, module M5 was significantly enriched in phenylpropanoid and flavonoid metabolisms, and several crucial genes participating in anthocyanin biosynthesis were included, suggesting a major role of M5 in anthocyanin biosynthesis in cassava. Coexpression analyses further revealed that phenylalanine ammonia-lyase 1 (PAL1), anthocyanidin synthase (ANS), and flavanone 3-hydroxylase (F3H) were the hub genes with most connections to others. Four transcription factors and three cis-regulatory motifs which might involve in anthocyanin biosynthesis regulation were also explored. Finally, a conserved coexpression network, covering the entire pathway of anthocyanin biosynthesis, was revealed among cassava, Arabidopsis thaliana (L.), and rice (Oryza sativa L.). The results provide valuable information to the key genes and regulatory networks of anthocyanin biosynthesis, and also lay a useful foundation for the genetic improvement in cassava.

Adoption and Promotion of Resilient Crops for Climate Risk Mitigation and Import Substitution: A Case Analysis of Cassava for South African Agriculture

Cassava is an important starchy root crop grown globally in tropical and subtropical regions. The ability of cassava to withstand difficult growing conditions and long-term storability underground makes it a resilient crop, contributing to food security. Historically, small-scale farmers have grown cassava as a minor crop in the far north-eastern part of the country. However, there is an initiative to scale up cassava production, with two discrete areas of interest: large-scale production for industrial starch, and expanding its footprint as a food security crop for small-scale farmers, especially in the context of climate change. In this scoping study, production, processing and marketing data for cassava were accessed from the FAO and US Commercial trade databases. Other domestic market and demand analysis case studies were also explored. There is no cassava data available for South Africa. The study indicated that South Africa imports more than 66,000 tons of starch annually, of which 33% is cassava starch, showing the availability of a local market. The potential of cassava for the South African economy is discussed. Significant industrial opportunities exist for the production and use of cassava in South Africa. However, the realization of these opportunities will depend on the reliable supply of good quality cassava roots. However, the lack of a well-established cassava research program, and a lack of an existing value chain for the industrial scale cassava production and processing are barriers to the development of cassava industry in South Africa. As the initial step to the development of a successful cassava industry, high potential germplasm is imported, characterized and bred for local conditions to ensure the sustainable primary production of cassava. Subsequently, industrial value chains will need to be developed as the optimization of the breeding and agronomy of the crop are completed, and yield potentials are quantified in the different regions of the country.

Highly dynamic, coordinated, and stage-specific profiles are revealed by a multi-omics integrative analysis during tuberous root development in cassava

Cassava (Manihot esculenta) is an important starchy root crop that provides food for millions of people worldwide, but little is known about the regulation of the development of its tuberous root at the multi-omics level. In this study, the transcriptome, proteome, and metabolome were examined in parallel at seven time-points during the development of the tuberous root from the early to late stages of its growth. Overall, highly dynamic and stage-specific changes in the expression of genes/proteins were observed during development. Cell wall and auxin genes, which were regulated exclusively at the transcriptomic level, mainly functioned during the early stages. Starch biosynthesis, which was controlled at both the transcriptomic and proteomic levels, was mainly activated in the early stages and was greatly restricted during the late stages. Two main branches of lignin biosynthesis, coniferyl alcohol and sinapyl alcohol, also functioned during the early stages of development at both the transcriptomic and proteomic levels. Metabolomic analysis further supported the stage-specific roles of particular genes/proteins. Metabolites related to lignin and flavonoid biosynthesis showed high abundance during the early stages, those related to lipids exhibited high abundance at both the early and middle stages, while those related to amino acids were highly accumulated during the late stages. Our findings provide a comprehensive resource for broadening our understanding of tuberous root development and will facilitate future genetic improvement of cassava.

Genome-wide association analysis reveals new insights into the genetic architecture of defensive, agro-morphological and quality-related traits in cassava

Key messageMore than 40 QTLs associated with 14 stress-related, quality and agro-morphological traits were identified. A catalogue of favourable SNP markers for MAS and a list of candidate genes are provided.Cassava (Manihot esculenta) is one of the most important starchy root crops in the tropics due to its adaptation to marginal environments. Genetic progress in this clonally propagated crop can be accelerated through the discovery of markers and candidate genes that could be used in cassava breeding programs. We carried out a genome-wide association study (GWAS) using a panel of 5130 clones developed at the International Institute of Tropical Agriculture—Nigeria. The population was genotyped at more than 100,000 SNP markers via genotyping-by-sequencing (GBS). Genomic regions underlying genetic variation for 14 traits classified broadly into four categories: biotic stress (cassava mosaic disease and cassava green mite severity); quality (dry matter content and carotenoid content) and plant agronomy (harvest index and plant type) were investigated. We also included several agro-morphological traits related to leaves, stems and roots with high heritability. In total, 41 significant associations were uncovered. While some of the identified loci matched with those previously reported, we present additional association signals for the traits. We provide a catalogue of favourable alleles at the most significant SNP for each trait-locus combination and candidate genes occurring within the GWAS hits. These resources provide a foundation for the development of markers that could be used in cassava breeding programs and candidate genes for functional validation.

Macro- and Micronutrients from Traditional Food Plants Could Improve Nutrition and Reduce Non-Communicable Diseases of Islanders on Atolls in the South Pacific.

Pacific Islanders have paid dearly for abandoning traditional diets, with diabetes and other non-communicable diseases (NCD) widespread. Starchy root crops like sweet potato, taro, and cassava are difficult to grow on the potassium-deficient soils of atolls, and high energy, low nutrient imported foods and drinks are popular. Nutritious, leafy food plants adapted to alkaline, salty, coral soils could form part of a food system strategy to reduce NCD rates. This project targeted four atolls south of Tarawa, Kiribati, and was later extended to Tuvalu. Mineral levels in diverse, local leafy food plants were compared to reveal genotype–environment interactions. Food plants varied in ability to accumulate minerals in leaves and in tolerance of mineral-deficient soils. Awareness activities which included agriculture, health, and education officers targeted atoll communities. Agriculture staff grew planting material in nurseries and provided it to farmers. Rejuvenation of abandoned giant swamp taro pits to form diversified nutritious food gardens was encouraged. Factsheets promoted the most suitable species from 24 analyzed, with multiple samples of each. These included Cnidoscolus aconitifolius (chaya), Pseuderanthemum whartonianum (ofenga), Polyscias scutellaria (hedge panax), and Portulaca oleracea (purslane). The promoted plants have been shown in other studies to have anti-NCD effects. Inclusion of the findings in school curricula and practical application in the form of demonstration school food gardens, as well as increased uptake by farmers, are needed. Further research is needed on bioavailability of minerals in plants containing phytates and tannins.

Development and Performance Evaluation of Automated Cassava-Grating Machine

Performance and economic returns of developed automated cassava-grating machine was investigated. The equipment has a realistic functional efficiency of 91.5% and 88.4% for manually and electrically powered operation with the discharge capacity 4.04 and 3.66 tons per day respectively. Simulation of its economic analysis shows between $2.6 and $3.0 could be saved while using automated cassava grater over manual system for 1-ton of cassava tuber. At 0.01 and 0.05 level of significance, it showed that the machine has a good economic potential over the convection method of grating. It saves time and labour requirements by a factor of 0.68. Design of a Cassava grating machine is dual-mode in operation; it is powered both manually and mechanically. This feature makes it useful in the rural areas where there is erratic or no power supply. Cassava is fed into machine through the hopper down to the granting drum, which rotates at a pre-set constant speed. Cassava is an important starchy root crop of the tropical world, the need to mechanize its growing and processing cannot be overemphasised.

Literary evidence for taro in the ancient Mediterranean: A chronology of names and uses in a multilingual world.

Taro, Colocasia esculenta (L.) Schott, is a vegetable and starchy root crop cultivated in Asia, Oceania, the Americas, Africa, and the Mediterranean. Very little is known about its early history in the Mediterranean, which previous authors have sought to trace through Classical (Greek and Latin) texts that record the name colocasia (including cognates) from the 3rd century BC onwards. In ancient literature, however, this name also refers to the sacred lotus, Nelumbo nucifera Gaertn. and its edible rhizome. Like taro, lotus is an alien introduction to the Mediterranean, and there has been considerable confusion regarding the true identity of plants referred to as colocasia in ancient literature. Another early name used to indicate taro was arum, a name already attested from the 4th century BC. Today, this name refers to Arum, an aroid genus native to West Asia, Europe, and the Mediterranean. Our aim is to explore historical references to taro in order to clarify when and through which routes this plant reached the Mediterranean. To investigate Greek and Latin texts, we performed a search using the Thesaurus Linguae Graecae (TLG) and the Thesaurus Linguae Latinae (TLL), plus commentaries and English and French translations of original texts. Results show that while in the early Greek and Latin literature the name kolokasia (Greek κολοκάσια) and its Latin equivalent colocasia refer to Nelumbo nucifera Gaertn., after the 4th century AD a poorly understood linguistic shift occurs, and colocasia becomes the name for taro. We also found that aron (Greek ἄρον) and its Latin equivalent arum are names used to indicate taro from the 3rd century BC and possibly earlier.

Prediction of cassava protein interactome based on interolog method

Cassava is a starchy root crop whose role in food security becomes more significant nowadays. Together with the industrial uses for versatile purposes, demand for cassava starch is continuously growing. However, in-depth study to uncover the mystery of cellular regulation, especially the interaction between proteins, is lacking. To reduce the knowledge gap in protein-protein interaction (PPI), genome-scale PPI network of cassava was constructed using interolog-based method (MePPI-In, available at http://bml.sbi.kmutt.ac.th/ppi). The network was constructed from the information of seven template plants. The MePPI-In included 90,173 interactions from 7,209 proteins. At least, 39 percent of the total predictions were found with supports from gene/protein expression data, while further co-expression analysis yielded 16 highly promising PPIs. In addition, domain-domain interaction information was employed to increase reliability of the network and guide the search for more groups of promising PPIs. Moreover, the topology and functional content of MePPI-In was similar to the networks of Arabidopsis and rice. The potential contribution of MePPI-In for various applications, such as protein-complex formation and prediction of protein function, was discussed and exemplified. The insights provided by our MePPI-In would hopefully enable us to pursue precise trait improvement in cassava.