Novel SNP markers and other stress-related genomic regions associated with nitrogen use efficiency in cassava

Cassava productivity is constrained by low soil nitrogen, which is predominant in most cassava-growing regions in the tropics and subtropical agroecology. Improving the low nitrogen tolerance of cassava has become an important breeding objective. The current study aimed to develop cassava varieties with improved nitrogen use efficiency by identifying genomic regions and candidate genes linked to nitrogen use efficiency in cassava. A genome-wide association study (GWAS) was performed using the Genome Association and Prediction Integrated Tool (GAPIT). A panel of 265 diverse cassava genotypes was phenotyped for 10 physiological and agronomic traits under optimum and low-nitrogen regimes. Whole-genome genotyping of these cassava cloneswas performed using the Diversity Arrays Technology (DArTseq) sequencing platform. A total of 68,814 single nucleotide polymorphisms (SNPs) were identified, which were spread across the entire 18 chromosomes of the cassava genome, of which 52 SNPs at various densities were found to be associated with nitrogen use efficiency in cassava and other yield-related traits. The putative genes identified through GWAS, especially those with significant associated SNP markers for NUE and related traits have the potential, if deployed appropriately, to develop cassava varieties with improved nitrogen use efficiency, which would translate to a reduction in the economic and environmental cost of cassava production.

Positive Regulatory Roles of Manihot esculenta HAK5 under K+ Deficiency or High Salt Stress

HAK/KUP/KT family members have been identified as playing key roles in K+ uptake and salt tolerance in numerous higher plants. However, their functions in cassava (Manihot esculenta Cantz) remain unknown. In this study, a gene encoding for a high-affinity potassium transporter (MeHAK5) was isolated from cassava and its function was investigated. Subcellular localization analysis showed that MeHAK5 is a plasma membrane-localized transporter. RT-PCR and RT-qPCR indicated that MeHAK5 is predominantly expressed in cassava roots, where it is upregulated by low potassium or high salt; in particular, its highest expression levels separately increased by 2.2 and 2.9 times after 50 µM KCl and 150 mM NaCl treatments. When heterologously expressed in yeast, MeHAK5 mediated K+ uptake within the cells of the yeast strain CY162 and rescued the salt-sensitive phenotype of AXT3K yeast. MeHAK5 overexpression in transgenic Arabidopsis plants exhibited improved growth and increased shoot K+ content under low potassium conditions. Under salt stress, MeHAK5 transgenic Arabidopsis plants accumulated more K+ in the shoots and roots and had reduced Na+ content in the shoots. As a result, MeHAK5 transgenic Arabidopsis demonstrated a more salt-tolerant phenotype. These results suggest that MeHAK5 functions as a high-affinity K+ transporter under K+ starvation conditions, improving K+/Na+ homeostasis and thereby functioning as a positive regulator of salt stress tolerance in transgenic Arabidopsis. Therefore, MeHAK5 may be a suitable candidate gene for improving K+ utilization efficiency and salt tolerance.

Gender-inclusive consumer studies improve cassava breeding in Nigeria

Including gender research in cassava breeding makes it easier for farmers to adopt new varieties that meet the specific needs and preferences of both male and female farmers, leading to increased adoption of new varieties, improved productivity, and better economic outcomes for the entire farming community. Gender was included in 2013 in variety development at the National Root Crops Research Institute (NRCRI), Umudike, Nigeria in response to the dis-adoption of some varieties by farmers who had not been part of varietal development from the start, and in light of social roles which influence the responsibilities, resources and livelihood outcomes of men, women and youths. Gender inclusion has given plant breeders accurate information about the cassava traits preferred by all end-users, not just male farmers. At NRCRI, gender studies intensified in the last 5 years, contributing to the development and release of improved varieties. Quantitative and qualitative research by the gender cross-cutting team modeled trait profiling and consumer preferences, to aid demand-led breeding. Some of the methods were acquired at several trainings on how to quantify qualitative responses for prioritization. Gender research techniques include participatory varietal selection (PVS), participatory plant breeding (PPB), mother-baby trials, focus group discussions (FGD), surveys, value chain mapping, G+ tools, experiments in farmer field schools (FFS), demonstration farms, and tricot. These gave the cross-cutting team a better understanding of gender relations, power, decision-making, ownership and control of resources, and have mitigated operational and field challenges during the surveys. These methods also elicited feedback from end-users that led to better naming of newly released varieties, reflecting perceptions of agronomic performance, and food qualities, which made the varieties easier to identify and remember.

Identifying genetically redundant accessions in the world's largest cassava collection

Crop diversity conserved in genebanks facilitates the development of superior varieties, improving yields, nutrition, adaptation to climate change and resilience against pests and diseases. Cassava (Manihot esculenta) plays a vital role in providing carbohydrates to approximately 500 million people in Africa and other continents. The International Center for Tropical Agriculture (CIAT) conserves the largest global cassava collection, housing 5,963 accessions of cultivated cassava and wild relatives within its genebank. Efficient genebank management requires identifying and eliminating genetic redundancy within collections. In this study, we optimized the identification of genetic redundancy in CIAT's cassava genebank, applying empirical distance thresholds, and using two types of molecular markers (single-nucleotide polymorphism (SNP) and SilicoDArT) on 5,302 Manihot esculenta accessions. A series of quality filters were applied to select the most informative and high-quality markers and to exclude low-quality DNA samples. The analysis identified a total of 2,518 and 2,526 (47 percent) distinct genotypes represented by 1 to 87 accessions each, using SNP or SilicoDArT markers, respectively. A total of 2,776 (SNP) and 2,785 (SilicoDArT) accessions were part of accession clusters with up to 87 accessions. Comparing passport and historical characterization data, such as pulp color and leaf characteristic, we reviewed clusters of genetically redundant accessions. This study provides valuable guidance to genebank curators in defining minimum genetic-distance thresholds to assess redundancy within collections. It aids in identifying a subset of genetically distinct accessions, prioritizing collection management activities such as cryopreservation and provides insights for follow-up studies in the field, potentially leading to removal of duplicate accessions.

Estimation of Genetic Diversity and Number of Unique Genotypes of Cassava Germplasm from Burkina Faso Using Microsatellite Markers

Genetic diversity is very important in crop improvement. This study was carried out to assess the genetic diversity and the number of unique multilocus genotypes (MLGs) in a cassava collection in Burkina Faso. To achieve this objective, 130 cassava accessions were genotyped using 32 simple sequence repeat (SSR) markers. The results revealed that among these markers, twelve (12) were highly informative, with polymorphic information content (PIC) values greater than 0.50; twelve (12) were moderately informative, with PIC values ranging between 0.25 and 0.50; and eight (8) were not very informative, with PIC values lower than 0.25. A moderate level of genetic diversity was found for the population, indicated by the average expected heterozygosity (0.45) and the observed heterozygosity (0.48). About 83.8% of unique multilocus genotypes were found in the cassava collection, indicating that SSR markers seem to be most appropriate for MLG identification. Population structure analysis based on hierarchical clustering identified two subpopulations and the Bayesian approach suggested five clusters. Additionally, discriminant analysis of principal components (DAPC) separated the cassava accessions into 13 subpopulations. A comparison of these results and those of a previous study using single nucleotide polymorphisms (SNP) suggests that each type of marker can be used to assess the genetic structure of cassava grown in Burkina Faso.

Cassava molecular genetics and genomics for enhanced resistance to diseases and pests

Cassava (Manihot esculenta) is one of the most important sources of dietary calories in the tropics, playing a central role in food and economic security for smallholder farmers. Cassava production is highly constrained by several pests and diseases, mostly cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). These diseases cause significant yield losses, affecting food security and the livelihoods of smallholder farmers. Developing resistant varieties is a good way of increasing cassava productivity. Although some levels of resistance have been developed for some of these diseases, there is observed breakdown in resistance for some diseases, such as CMD. A frequent re-evaluation of existing disease resistance traits is required to make sure they are still able to withstand the pressure associated with pest and pathogen evolution. Modern breeding approaches such as genomic-assisted selection in addition to biotechnology techniques like classical genetic engineering or genome editing can accelerate the development of pest- and disease-resistant cassava varieties. This article summarizes current developments and discusses the potential of using molecular genetics and genomics to produce cassava varieties resistant to diseases and pests.

Characterization of the Cassava Mycobiome in Symptomatic Leaf Tissues Displaying Cassava Superelongation Disease

Superelongation disease (SED) is a fungal disease that affects cassava in the Caribbean. The symptoms include the appearance of dry necrotic spots and lesions on the leaves, which may severely affect the plant yield. However, the primary causal pathogen is difficult to culture and isolate in the lab because of its slow growth and potential contamination from faster-growing organisms. In addition, the leaf symptoms can be confused with those caused by other pathogens that produce similar necrotic spots and scab-like lesions. There is also little or no information on the contribution of endophytes, if any, to disease symptoms in cassava, a plant where the disease is prevalent. Therefore, this study aimed to characterize the fungal communities in cassava associated with SED symptoms by analyzing gross fungal morphology and performing metagenomics profiling. First, several individual pathogenic fungi were isolated and cultured from diseased cassava leaf tissues from seven locations in Barbados (BB). Both culture isolation and molecular community analyses showed the presence of several other fungi in the disease microenvironment of symptomatic cassava leaves. These included Fusarium, Colletotrichum, and Alternaria species and the suspected species Elsinoë brasiliensis synonym Sphaceloma manihoticola. Additionally, a community analysis using ITS2 amplicon sequencing of 21 symptomatic leaf tissues from BB, St. Vincent and the Grenadines (SVG), Trinidad and Tobago (TT), and Jamaica (JA) revealed that the disease symptoms of superelongation may also result from the interactions of fungal communities in the mycobiome, including Elsinoë species and other fungi such as Colletotrichum, Cercospora, Alternaria, and Fusarium. Therefore, we suggest that examining the pathobiome concept in SED in the future is necessary.

Use of sensory and physico-chemical parameters to understand consumer perception of attiéké, a fermented cassava product

BACKGROUND

While cassava breeding research programs initially focused on agronomic performance, in recent years, they have considered the processability and the organoleptic properties of final product, to increase the adoption of new varieties. A main cassava foodstuff is attiéké, a fermented and granular product. It is therefore necessary to determine criteria used by attiéké processors to select raw cassava and the liking drivers of consumers. This study assessed the attiéké production process, the quality criteria of attiéké, the drivers of consumer acceptance and their thresholds.

RESULTS

Total processing yield of attiéké varied according to cassava variety and depends primarily on the fermentation-pressing yield. However, it was not correlated neither with the peeling yield nor with morphological characteristics of cassava roots. The production of a ton of attiéké requires about 150 hours. Dry matter, organic acids, soluble sugars, total pectin, and pH of raw material and attiéké varied depending on cassava variety. Ten discriminating sensory attributes of attiéké were identified. Consumer testing showed that attiéké overall liking is associated with sourness, texture, and brightness. Acceptable sensory score threshold was 1.67-2.18 for sour odor, 4.75 to 6.3 for cohesiveness, and 5.4 to 6.3 for 'mouth-filled sensation'. Attiéké dry matter negatively correlated with attiéké pectin content (r = -0.680), and positively with cohesiveness and moldability.

CONCLUSIONS

Several potential solutions are discussed to improve the adoption of cassava varieties for attiéké production. However, further studies will be carried out to translate the sensory thresholds of texture attributes into robust instrumental methods because texture is the important attribute of attiéké besides sourness. This article is protected by copyright. All rights reserved.

SEGS-1 a cassava genomic sequence increases the severity of African cassava mosaic virus infection in Arabidopsis thaliana

Cassava is a major crop in Sub-Saharan Africa, where it is grown primarily by smallholder farmers. Cassava production is constrained by Cassava mosaic disease (CMD), which is caused by a complex of cassava mosaic begomoviruses (CMBs). A previous study showed that SEGS-1 (sequences enhancing geminivirus symptoms), which occurs in the cassava genome and as episomes during viral infection, enhances CMD symptoms and breaks resistance in cassava. We report here that SEGS-1 also increases viral disease severity in Arabidopsis thaliana plants that are co-inoculated with African cassava mosaic virus (ACMV) and SEGS-1 sequences. Viral disease was also enhanced in Arabidopsis plants carrying a SEGS-1 transgene when inoculated with ACMV alone. Unlike cassava, no SEGS-1 episomal DNA was detected in the transgenic Arabidopsis plants during ACMV infection. Studies using Nicotiana tabacum suspension cells showed that co-transfection of SEGS-1 sequences with an ACMV replicon increases viral DNA accumulation in the absence of viral movement. Together, these results demonstrated that SEGS-1 can function in a heterologous host to increase disease severity. Moreover, SEGS-1 is active in a host genomic context, indicating that SEGS-1 episomes are not required for disease enhancement.

The aquaporin MePIP2;7 improves MeMGT9-mediated Mg2 + acquisition in cassava

Aquaporins are important transmembrane water transport proteins which transport water and several neutral molecules. However, how aquaporins are involved in the synergistic transport of Mg2+ and water remains poorly understood. Here, we found that the cassava aquaporin MePIP2;7 was involved in Mg2+ transport through interaction with MeMGT9, a lower affinity magnesium transporter protein. Knockdown of MePIP2;7 in cassava led to magnesium deficiency in basal mature leaves with chlorosis and necrotic spots on their edges and starch over-accumulation. Mg2+ content was significantly decreased in leaves and roots of MePIP2;7-RNA interference (PIP-Ri) plants grown in both field and Mg2+ -free hydroponic solution. Xenopus oocyte injection analysis verified that MePIP2;7 possessed the ability to transport water only and MeMGT9 was responsible for Mg2+ efflux. More importantly, MePIP2;7 improved the transportability of Mg2+ via MeMGT9 as verified using the CM66 mutant complementation assay and Xenopus oocytes expressing system. Yeast two-hybrid, bimolecular fluorescence complementation, co-localization, and co-immunoprecipitation assays demonstrated the direct protein-protein interaction between MePIP2;7 and MeMGT9 in vivo. Mg2+ flux was significantly elevated in MePIP2;7-overexpressing lines in hydroponic solution through non-invasive micro-test technique analysis. Under Mg2+ -free condition, the retarded growth of PIP-Ri transgenic plants could be recovered with Mg2+ supplementation. Taken together, our results demonstrated the synergistic effect of the MePIP2;7 and MeMGT9 interaction in regulating water and Mg2+ absorption and transport in cassava.

Radiological Analysis of Cassava Samples From a Coal Mining Area in Enugu State Nigeria

Cassava holds a vital position as a staple food in Nigeria, forming a significant portion of the daily diet for the population. Unfortunately, food intake can serve as a pathway for radiological contamination in humans and animals. In this study conducted in an old coal mining area in Enugu State, Nigeria, cassava samples from the area were analyzed using gamma ray spectroscopy. The results revealed significant mean activity concentrations of the radionuclides 40K, 226Ra, and 232Th in camp 1, camp 2, and Pottery areas. The activity concentration ranged from 193.68 to 300.92 Bq/kg for 40 K, 23.03 to 37.24 Bq/kg for 226Ra, and 135.33 to 158.43 Bq/kg for 232Th, respectively. Of concern is the total mean annual effective dose resulting from exposure to these 3 observed radionuclides that was calculated to be 2.03 mSv/yr. This value exceeds the recommended limit of 1 mSv/yr, indicating potential health risks associated with the radiological contamination from cassava consumption in this region. In summary, the study shows that cassava samples from the investigated area exhibited elevated levels of radiotoxicity, raising concerns about the safety of consuming cassava from this region as a food source.

MeGLYI-13, a Glyoxalase I Gene in Cassava, Enhances the Tolerance of Yeast and Arabidopsis to Zinc and Copper Stresses

Although zinc and copper are the two essential nutrients necessary for plant growth, their excessive accumulation in soil not only causes environmental pollution but also seriously threatens human health and inhibits plant growth. The breeding of plants with novel zinc or copper toxicity tolerance capacities represents one strategy to address this problem. Glyoxalase I (GLYI) family genes have previously been suggested to be involved in the resistance to a wide range of abiotic stresses, including those invoked by heavy metals. Here, a MeGLYI-13 gene cloned from a cassava SC8 cultivar was characterized with regard to its potential ability in resistance to zinc or copper stresses. Sequence alignment indicated that MeGLYI-13 exhibits sequence differences between genotypes. Transient expression analysis revealed the nuclear localization of MeGLYI-13. A nuclear localization signal (NLS) was found in its C-terminal region. There are 12 Zn2+ binding sites and 14 Cu2+ binding sites predicted by the MIB tool, of which six binding sites were shared by Zn2+ and Cu2+. The overexpression of MeGLYI-13 enhanced both the zinc and copper toxicity tolerances of transformed yeast cells and Arabidopsis seedlings. Taken together, our study shows the ability of the MeGLYI-13 gene to resist zinc and copper toxicity, which provides genetic resources for the future breeding of plants resistant to zinc and copper and potentially other heavy metals.

Integrated Analysis of Morphological, Physiological, Anatomical and Molecular Responses of Cassava Seedlings to Different Light Qualities

Light quality is highly important for growth control of in vitro plant cultures. Here, we investigated the effect of blue light (BL), red light (RL) and combined red and blue light (RBL) on in vitro cassava growth. Our results indicate that RL facilitated radial elongation of cassava and increased stomatal conductance as well as glucose, sucrose, fructose and starch content in leaves and cellulose content in the stem. It also enhanced SOD and POD activities but decreased the stomatal density and chlorophyll and carotenoid content in leaves. In addition, RL leads to shorter palisade cells, denser chloroplasts and more starch granules. These phenotypic changes were inverted following BL treatment. The expression levels of photosynthesis-related genes MeLHCA1, MeLHCA3, MePSB27-2, MePSBY, MePETE1 and MePNSL2 in leaves were at their lowest following RL treatment, while the expression levels of MePSB27-2, MePSBY, MePETE1 and MePNSL2 were at their highest after BL treatment. The phenotypic changes after RBL treatment were between the values observed for the RL and BL treatments alone. Moreover, the responses of SC8 and SC9 cassava varieties to light quality were largely conserved. As such, we believe that the results of this study lay the foundation for controlling the in vitro growth of cassava seedlings by light quality.

Isolation and Identification of Endophytic Bacteria Bacillus sp. ME9 That Exhibits Biocontrol Activity against Xanthomonas phaseoli pv. manihotis

In recent years, the bacterial blight of cassava has caused substantial economic losses to the Chinese cassava industry. Chemical control methods have become the primary approach to control this disease; however, their widespread usage and harmful residues have raised concerns about environmental pollution. In order to avoid this, it is urgent to seek a green ecological method to prevent and control it. Biological control through the utilization of microorganisms not only effectively inhibits the disease, but also gives consideration to environmental friendliness. Therefore, investigating an endophytic biological control method for cassava bacterial blight is of great importance. In this study, cassava leaf tissues were used as test specimens in order to isolate endophytic bacteria by using dilution and separation methods. Bacillus ME9, derived from cassava endophytic bacteria, exhibits good antagonism against a diverse range of pathogens, including Xpm11. Its genome consists of a series of genes encoding antibacterial lipopeptides, which may be directly related to its antibacterial capabilities. Furthermore, inoculation resulted in a substantial change in the diversity of the endophytic bacterial community, characterized by improved diversity, and displayed an obvious inhibition of pathogenic bacterial growth, demonstrating successful colonization within plants. The results laid a foundation and provided theoretical support for the development and utilization of cassava endophytic bacterial diversity and endogenous disease control strategies.

Development and validation of near-infrared spectroscopy procedures for prediction of cassava root dry matter and amylose contents in Ugandan cassava germplasm

BACKGROUND

Cassava utilization for food and/or industrial products depends on inherent properties of root dry matter content (DMC) and the starch fraction of amylose content (AC). Accordingly, in the present study, near-infrared reflectance spectroscopy (NIRS) models were developed to aid breeding and selection of DMC and AC as critical industrial traits taking care of root sample preparation and cassava germplasm diversity available in Uganda.

RESULTS

Upon undertaking calibrations and cross-validations, best models were adopted for validation. DMC in calibration samples ranged from 20 to 45 g 100g-1 , whereas, for amylose content, it ranged from 14 to 33 g 100g-1 . In the validation set, average DMC was 29.5 g 100g-1 , whereas, for amylose content, it was 24.64 g 100g-1 . For DMC, a modified partial least square regression model had regression coefficients (R2 ) of 0.98 and 0.96, respectively, in the calibration and validation set. These were also associated with low bias (-0.018) and ratio of performance deviation that ranged from 4.7 to 5.0. In addition, standard error of prediction values ranged from 0.9 g 100g-1 to 1.06 g 100g-1 . For AC, the regression coefficient was 0.91 for the calibration set and 0.94 for the validation set. A bias equivalent to -0.03 and a ratio of performance deviation of 4.23 were observed.

CONCLUSION

These findings confirm the robustness of NIRS in the estimation of dry matter content and amylose content in cassava roots and thus justify its use in routine cassava breeding operations. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Transforming Nigerian Food Systems Through Their Backbones: Lessons From a Decade of Staple Crop Biofortification Programing

This article presents the evolution of the biofortification program in Nigeria over the last decade and the role of interdisciplinary research in informing cost-effective, efficient, and inclusive development; implementation; and scaling of this program. Launched in 2011 to improve Nigeria's food systems to deliver accessible and affordable nutrients through commonly consumed staples, the Nigeria biofortification program was implemented through an effective partnership between the CGIAR and public, private, and civil society sectors at federal, state, and local levels. By the end of 2021, several biofortified varieties of Nigeria's 2 main staples, namely cassava and maize, were officially released for production by smallholders, with several biofortified varieties of other key staples (including pearl millet, rice, and sorghum) either under testing or in the release pipeline. In 2021, the program was estimated to benefit 13 million Nigerians consuming biofortified cassava and maize varieties. The evidence on the nutritional impact, consumer and farmer acceptance, and cost-effective scalability of biofortified crops documented by the program resulted in the integration of biofortified crops in several key national public policies and social protection programs; private seed and food company products/investments, as well as in humanitarian aid.

Going beyond consensus genome sequences: An innovative SNP-based methodology reconstructs different Ugandan cassava brown streak virus haplotypes at a nationwide scale in Rwanda

Cassava Brown Streak Disease (CBSD), which is caused by cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV), represents one of the most devastating threats to cassava production in Africa, including in Rwanda where a dramatic epidemic in 2014 dropped cassava yield from 3.3 million to 900,000 tonnes (1). Studying viral genetic diversity at the genome level is essential in disease management, as it can provide valuable information on the origin and dynamics of epidemic events. To fill the current lack of genome-based diversity studies of UCBSV, we performed a nationwide survey of cassava ipomovirus genomic sequences in Rwanda by high-throughput sequencing (HTS) of pools of plants sampled from 130 cassava fields in thirteen cassava-producing districts, spanning seven agro-ecological zones with contrasting climatic conditions and different cassava cultivars. HTS allowed the assembly of a nearly complete consensus genome of UCBSV in twelve districts. The phylogenetic analysis revealed high homology between UCBSV genome sequences, with a maximum of 0.8 per cent divergence between genomes at the nucleotide level. An in-depth investigation based on Single Nucleotide Polymorphisms (SNPs) was conducted to explore the genome diversity beyond the consensus sequences. First, to ensure the validity of the result, a panel of SNPs was confirmed by independent reverse transcription polymerase chain reaction (RT-PCR) and Sanger sequencing. Furthermore, the combination of fixation index (FST) calculation and Principal Component Analysis (PCA) based on SNP patterns identified three different UCBSV haplotypes geographically clustered. The haplotype 2 (H2) was restricted to the central regions, where the NAROCAS 1 cultivar is predominantly farmed. RT-PCR and Sanger sequencing of individual NAROCAS1 plants confirmed their association with H2. Haplotype 1 was widely spread, with a 100 per cent occurrence in the Eastern region, while Haplotype 3 was only found in the Western region. These haplotypes' associations with specific cultivars or regions would need further confirmation. Our results prove that a much more complex picture of genetic diversity can be deciphered beyond the consensus sequences, with practical implications on virus epidemiology, evolution, and disease management. Our methodology proposes a high-resolution analysis of genome diversity beyond the consensus between and within samples. It can be used at various scales, from individual plants to pooled samples of virus-infected plants. Our findings also showed how subtle genetic differences could be informative on the potential impact of agricultural practices, as the presence and frequency of a virus haplotype could be correlated with the dissemination and adoption of improved cultivars.

Genome-Wide Survey of the RWP-RK Gene Family in Cassava (Manihot esculenta Crantz) and Functional Analysis

The plant-specific RWP-RK transcription factor family plays a central role in the regulation of nitrogen response and gametophyte development. However, little information is available regarding the evolutionary relationships and characteristics of the RWP-RK family genes in cassava, an important tropical crop. Herein, 13 RWP-RK proteins identified in cassava were unevenly distributed across 9 of the 18 chromosomes (Chr), and these proteins were divided into two clusters based on their phylogenetic distance. The NLP subfamily contained seven cassava proteins including GAF, RWP-RK, and PB1 domains; the RKD subfamily contained six cassava proteins including the RWP-RK domain. Genes of the NLP subfamily had a longer sequence and more introns than the RKD subfamily. A large number of hormone- and stress-related cis-acting elements were found in the analysis of RWP-RK promoters. Real-time quantitative PCR revealed that all MeNLP1-7 and MeRKD1/3/5 genes responded to different abiotic stressors (water deficit, cold temperature, mannitol, polyethylene glycol, NaCl, and H2O2), hormonal treatments (abscisic acid and methyl jasmonate), and nitrogen starvation. MeNLP3/4/5/6/7 and MeRKD3/5, which can quickly and efficiently respond to different stresses, were found to be important candidate genes for further functional assays in cassava. The MeRKD5 and MeNLP6 proteins were localized to the cell nucleus in tobacco leaf. Five and one candidate proteins interacting with MeRKD5 and MeNLP6, respectively, were screened from the cassava nitrogen starvation library, including agamous-like mads-box protein AGL14, metallothionein 2, Zine finger FYVE domain containing protein, glyceraldehyde-3-phosphate dehydrogenase, E3 Ubiquitin-protein ligase HUWE1, and PPR repeat family protein. These results provided a solid basis to understand abiotic stress responses and signal transduction mediated by RWP-RK genes in cassava.

Valorization of Two African Typical Crops, Sorghum and Cassava, by the Production of Different Dry Pasta Formulations

Mediterranean diet is changing to keep up with the increasingly multiethnic Italian society. With food being considered as a means of integration, innovative foods capable of mixing different raw materials could be of interest. In this work, some of the most consumed African foods such as sorghum, cassava, and durum wheat were used to produce wholegrain spaghetti to valorize their nutritional and sensorial aspects and to combine Italian and foreign tastes. Different pasta formulations (cassava, semolina, cassava:semolina, cassava:sorghum, cassava:durum wheat whole meal, sorghum:semolina) were developed and compared for their content of proteins, total starch, resistant starch, amylose, fiber, total antioxidant capacity, ash, cooking quality and sensorial characteristics. The enrichment of cassava flour with durum wheat and sorghum wholegrain enhanced the total antioxidant capacity, protein, and fiber content with respect to 100% cassava pasta. The presence of cassava or sorghum resulted in a high diameter variability of pasta samples, lower water absorption, and shorter optimal cooking time with respect to semolina pasta. Sensory evaluation of cooked pasta revealed better scores in blends containing semolina. Although the obtained pasta samples were interesting for their nutritional aspects, further adjustments are required in the pasta-making process to improve pasta quality.

Drivers of consumer acceptability of cassava gari-eba food products across cultural and environmental settings using the Triadic Comparison of Technologies approach (tricot)

BACKGROUND

Nigeria and Cameroon are multi-ethnic countries with diverse preferences for food characteristics. This study aimed to inform cassava breeders on consumer-prioritized eba quality traits. Consumer testing was carried out using the triadic comparison of technologies (tricot). Diverse consumers in villages, towns and cities evaluated the overall acceptability of eba made from different cassava genotypes. Data from both countries were combined and linked to laboratory analyses of eba and the gari used to make it.

RESULTS

There is a strong preference for eba with higher cohesiveness and eba from gari with higher brightness and especially in Cameroon, with lower redness and yellowness. Relatively higher eba hardness and springiness values are preferred in the Nigerian locations, while lower values are preferred in Cameroon. Trends for solubility and swelling power of the gari differ between the two countries. This study also reveals that the older improved cassava genotype TMS30572 is a benchmark genotype with superior eba characteristics across different regions in Nigeria, while the recently released variety Game changer performs very well in Cameroon. In both locations, the recently released genotypes Obansanjo-2 and improved variety TM14F1278P0003 have good stability and overall acceptability for eba characteristics.

CONCLUSION

The wide acceptance of a single genotype across diverse geographical and cultural conditions in Nigeria, and three acceptable new improved varieties in both locations, indicates that consumers' preferences are surprisingly homogeneous for eba. This would enhance breeding efforts to develop varieties with wider acceptability and expand potential target areas for released varieties. This article is protected by copyright. All rights reserved.

Integrated Characterization of Cassava (Manihot esculenta) Pectin Methylesterase (MePME) Genes to Filter Candidate Gene Responses to Multiple Abiotic Stresses

Plant pectin methylesterases (PMEs) play crucial roles in regulating cell wall modification and response to various stresses. Members of the PME family have been found in several crops, but there is a lack of research into their presence in cassava (Manihot esculent), which is an important crop for world food security. In this research, 89 MePME genes were identified in cassava that were separated into two types (type-Ⅰ and type-Ⅱ) according to the existence or absence of a pro-region (PMEI domain). The MePME gene members were unevenly located on 17 chromosomes, with 19 gene pairs being identified that most likely arose via duplication events. The MePMEs could be divided into ten sub-groups in type-Ⅰ and five sub-groups in type-Ⅱ. The motif analysis revealed 11 conserved motifs in type-Ⅰ and 8 in type-Ⅱ MePMEs. The number of introns in the CDS region of type-Ⅰ MePMEs ranged between one and two, and the number of introns in type-Ⅱ MePMEs ranged between one and nine. There were 21 type-Ⅰ and 31 type-Ⅱ MePMEs that contained signal peptides. Most of the type-Ⅰ MePMEs had two conserved "RK/RLL" and one "FPSWVS" domain between the pro-region and the PME domain. Multiple stress-, hormone- and tissue-specific-related cis-acting regulatory elements were identified in the promoter regions of MePME genes. A total of five co-expressed genes (MePME1, MePME2, MePME27, MePME65 and MePME82) were filtered from different abiotic stresses via the use of UpSet Venn diagrams. The gene expression pattern analysis revealed that the expression of MePME1 was positively correlated with the degree of cassava postharvest physiological deterioration (PPD). The expression of this gene was also significantly upregulated by 7% PEG and 14 °C low-temperature stress, but slightly downregulated by ABA treatment. The tissue-specific expression analysis revealed that MePME1 and MePME65 generally displayed higher expression levels in most tissues than the other co-expressed genes. In this study, we obtain an in-depth understanding of the cassava PME gene family, suggesting that MePME1 could be a candidate gene associated with multiple abiotic tolerance.

Effects of Different Dietary Starch Sources and Digestible Lysine Levels on Carcass Traits, Serum Metabolites, Liver Lipid and Breast Muscle Protein Metabolism in Broiler Chickens

This study investigated the effects of digestible lysine (dLys) in different dietary starch sources on liver lipid metabolism and breast muscle protein metabolism in broiler chickens. The experimental design was a 3 × 3 two-factor completely randomized design. A total of 702 one-day-old male Arbor Acres Plus broilers were randomly divided into nine treatments of six replicate cages with thirteen birds each. The treatments consisted of three different starch sources (corn, cassava and waxy corn) with three different dLys levels (1.08%, 1.20% and 1.32%). The trial lasted from 1 to 21 days. Carcass traits, serum metabolites, breast muscle protein and liver lipid metabolism were evaluated. A significant interaction effect (p < 0.05) for dietary starch sources and dLys levels was noted in the percentage of abdominal fat and gene expression related to breast muscle protein metabolism throughout the experimental period. The waxy corn starch diet and a 1.08% dLys level in the diet increased both the percentage of abdominal fat (p < 0.01) and blood total cholesterol (p < 0.05) in the broilers. The waxy corn starch diet significantly upregulated the mRNA expressions of Eif4E, AMPK, FABP1, ACC and CPT1 (p < 0.05). The 1.32% dLys level significantly upregulated the mRNA expressions of mTOR, S6K1, Eif4E, AMPK and PPARα (p < 0.05) and significantly downregulated the mRNA expressions of MuRF and Atrogin-1 (p < 0.05). In summary, the waxy corn starch diet resulted in significantly higher expression levels of fat-synthesis-related genes than lipolysis-related genes, leading to abdominal fat deposition in broilers. Increasing the level of dLys in the diet increased the protein content in muscle by promoting protein synthesis and inhibiting protein degradation and also promoted the expression of lipolysis-related genes, thereby degrading the generation of abdominal fat in broilers. Our findings signify that increasing the dLys level to 1.32% when using the waxy corn starch diet could improve carcass traits.

Integrative analysis of metabolome and transcriptome reveals the mechanism of color formation in cassava (Manihot esculenta Crantz) leaves

Cassava (Manihot esculenta Crantz) leaves are often used as vegetables in Africa. Anthocyanins possess antioxidant, anti-inflammatory, anti-cancer, and other biological activities. They are poor in green leaves but rich in the purple leaves of cassava. The mechanism of anthocyanin's accumulation in cassava is poorly understood. In this study, two cassava varieties, SC9 with green leaves and Ziyehuangxin with purple leaves (PL), were selected to perform an integrative analysis using metabolomics and transcriptomics. The metabolomic analysis indicated that the most significantly differential metabolites (SDMs) belong to anthocyanins and are highly accumulated in PL. The transcriptomic analysis revealed that differentially expressed genes (DEGs) are enriched in secondary metabolites biosynthesis. The analysis of the combination of metabolomics and transcriptomics showed that metabolite changes are associated with the gene expressions in the anthocyanin biosynthesis pathway. In addition, some transcription factors (TFs) may be involved in anthocyanin biosynthesis. To further investigate the correlation between anthocyanin accumulation and color formation in cassava leaves, the virus-induced gene silencing (VIGS) system was used. VIGS-MeANR silenced plant showed the altered phenotypes of cassava leaves, partially from green to purple color, resulting in a significant increase of the total anthocyanin content and reduction in the expression of MeANR. These results provide a theoretical basis for breeding cassava varieties with anthocyanin-rich leaves.

Parasitoid Wasp Acerophagus papayae: A Promising Solution for the Control of Papaya Mealybug Paracoccus marginatus in Cassava Fields in Vietnam

Cassava is a valuable export commodity crop that is often attacked by pests, causing economic losses for this crop. The papaya mealybug Paracoccus marginatus has become a major pest of cassava in Vietnam. The parasitoid wasp Acerophagus papayae has been demonstrated to be the most efficient parasitoid wasp for controlling P. marginatus in many regions. We observed the occurrence of A. papayae in Vietnam, studied the biological characteristics of A. papayae, and investigated its parasitic activity on P. marginatus. The results showed that A. papayae occurred more frequently than Anagyrus loecki, another known parasitoid of P. marginatus. The lifespan of A. papayae was approximately 16 days. In the absence of hosts, a 50% honey solution was an essential diet to increase the longevity of both female and male of A. papayae. The second instar of P. marginatus was a suitable host stage for parasitism by A. papayae. Female A. papayae laid approximately 60.8 eggs within 17 days, mostly during the first 6 to 7 days. These findings suggest that A. papayae has the potential to control P. marginatus, and could inform the development of more effective pest management strategies for cassava crops in Vietnam and other regions affected by this pest.

Antioxidant, Anti-Inflammatory, and Anti-Cancer Properties of Amygdalin Extracted from Three Cassava Varieties Cultivated in Benin

Given that cancer is a disease that is rampant in the world and especially in Africa, where the population has enormous difficulty treating it, plants are a safer and less expensive alternative. Cassava is a plant species valued in Benin because of its numerous medicinal and nutritional virtues. This study evaluated the biological activities of amygdalin from the organs of three cassava varieties most commonly produced in Benin (BEN, RB, and MJ). HPLC analysis was used to quantify amygdalin in cassava organs and derivatives. Phytochemical screening was performed to determine secondary metabolite groups. DPPH and FRAP methods were used to assess antioxidant activity. Cytotoxicity of the extracts was tested on Artemia salina larvae. The anti-inflammatory activity was evaluated in vivo in an albino mouse paw edema model induced by 5% formalin. The anticancer activity was evaluated in vivo on Wistar rats rendered cancerous by 1,2-dimethylhydrazine (DMH) using 5-fluorouracil as a reference molecule. The results showed that the organs of all three-cassava varieties contained glycosides, flavonoids, saponosides, steroids, tannins, coumarins, and cyanogenic derivatives. Young stems and fresh cassava leaves had the highest amygdalin concentrations, with 11,142.99 µg 10 g-1 and 9251.14 µg 10 g-1, respectively. The Agbeli derivative was more concentrated in amygdalin, with a content of 401.56 µg 10 g-1 than the other derivatives. The antioxidant activity results showed that the amygdalin extracts were DPPH radical scavengers with IC50 values ranging from 0.18 mg mL-1 to 2.35 mg mL-1. The cytotoxicity test showed no toxicity of the extracts toward shrimp larvae. Administration of amygdalin extracts from the leaves of BEN and MJ varieties prevents inflammatory edema. The percentages of edema inhibition varied between 21.77% and 27.89%. These values are similar (p > 0.05) to those of acetylsalicylic acid (25.20%). Amygdalin extract of the BEN variety significantly (p < 0.0001) reduces edema. Both BEN extracts inhibited cancer induction with DMH. In preventive and curative treatments, rats fed with amygdalin extracts showed low anti-cancer activity under the effect of DMH and a significant difference in biochemical results. Thus, the organs of all three cassava varieties studied have secondary metabolites and good antioxidant activity. The leaves contain high levels of amygdalin and can be used as anti-inflammatory and anticancer agents.

Flower-inducing technology facilitates speed breeding in cassava

Cassava is a tropical crop that provides daily carbohydrates to more than 800 million people. New cassava cultivars with improved yield, disease resistance, and food quality are critical to end hunger and reduce poverty in the tropics. However, the progress of new cultivar development has been dragged down by difficulties obtaining flowers from desired parental plants to enable designed crosses. Inducing early flowering and increasing seed production are crucial to improving the efficiency of developing farmer-preferred cultivars. In the present study, we used breeding progenitors to evaluate the effectiveness of flower-inducing technology, including photoperiod extension, pruning, and plant growth regulators. Photoperiod extension significantly reduced the time to flowering in all 150 breeding progenitors, especially late-flowering progenitors which were reduced from 6-7 months to 3-4 months. Seed production was increased by using the combination of pruning and plant growth regulators. Combining photoperiod extension with pruning and the PGR 6-benzyladenine (synthetic cytokinin) produced significantly more fruits and seeds than only photoperiod extension and pruning. Another growth regulator, silver thiosulfate, commonly used to block the action of ethylene, did not show a significant effect on fruit or seed production when combined with pruning. The present study validated a protocol for flower induction in cassava breeding programs and discussed factors to consider in implementing the technology. By inducing early flowering and increasing seed production, the protocol helped move one step further for speed breeding in cassava.

Prediction of functional characteristics of gari (cassava flakes) using near-infrared reflectance spectrometry

Gari is a creamy, granular flour obtained from roasting fermented cassava mash. Its preparation involves several unit operations, including fermentation, which is essential in gari production. Fermentation brings about specific biochemical changes in cassava starch due to the actions of lactic acid bacteria. Consequently, it gives rise to organic acids and a significant reduction in the pH. Consumer preferences for gari are influenced by these changes and impact specific functional characteristics, which are often linked to cassava genotypes. Measurement of these functional characteristics is time-consuming and expensive. Therefore, this study aimed to develop high-throughput and less expensive prediction models for water absorption capacity, swelling power, bulk density, and dispersibility using Near-Infrared Reflectance Spectroscopy (NIRS). Gari was produced from 63 cassava genotypes using the standard method developed in the RTB foods project. The prediction model was developed by dividing the gari samples into two sets of 48 samples for calibration and 15 samples as the validation set. The gari samples were transferred into a ring cell cup and scanned on the NIRS machine within the Vis-NIR range of 400-2,498 nm wavelength, though only the NIR range of 800-2,400 nm was used to build the model. Calibration models were developed using partial least regression algorithms after spectra pre-processing. Also, the gari samples were analysed in the laboratory for their functional properties to generate reference data. Results showed an excellent coefficient of determination in calibrations (R² _Cal) of 0.99, 0.97, 0.97, and 0.89 for bulk density, swelling power, dispersibility, and water absorption capacity, respectively. Also, the performances of the prediction models were tested using an independent set of 15 gari samples. A good prediction coefficient (R² pred) and low standard error of prediction (SEP) was obtained as follows: Bulk density (0.98), Swelling power (0.93), WAC (0.68), Dispersibility (0.65), and solubility index (0.62), respectively. Therefore, NIRS prediction models in this study could provide a rapid screening tool for cassava breeding programs and food scientists to determine the food quality of cassava granular products (Gari).

When knowledge is not enough: barriers to recommended cassava processing in resource-constrained Kwango, Democratic Republic of Congo

Background

Despite interventions to provide knowledge and improve bitter cassava processing in the Democratic Republic of Congo (DRC), cassava processing is sub-optimal. Consumption of insufficiently processed bitter cassava is associated with konzo, a neurological paralytic disease.

Objective

This study aimed to explore barriers to appropriate cassava processing carried out by women in one deep rural, economically deprived area of DRC.

Methods

A qualitative design used focus group discussions (FGDs) and participant observation to collect data among purposively selected women aged 15-61 years in Kwango, DRC. Data were analyzed using thematic analysis.

Results

15 FGDs with 131 women and 12 observations of cassava processing were undertaken. Observations indicated women did not follow recommended cassava processing methods. Although women were knowledgeable about cassava processing, two main barriers emerged: access to water and lack of money. Accessing water from the river to process cassava was burdensome, and the cassava was at risk of being stolen by soaking it in the river; therefore, women shortened the processing time. Cassava was not only used as a staple food but also as a cash crop, which led to households shortening the processing time to reach the market quickly.

Conclusion

Knowledge about the risks of insufficient cassava processing and about safe processing methods alone is insufficient to change practices in a context of severe resource constraints. When planning nutrition interventions, it is critical to view the intervention in light of the socio-economic context in which the intervention will take place to improve its outcomes.

Integrated Metabolomic and Transcriptomic Analyses Reveals Sugar Transport and Starch Accumulation in Two Specific Germplasms of Manihot esculenta Crantz

As a starchy and edible tropical plant, cassava (Manihot esculenta Crantz) has been widely used as an industrial raw material and a dietary source. However, the metabolomic and genetic differences in specific germplasms of cassava storage root were unclear. In this study, two specific germplasms, M. esculenta Crantz cv. sugar cassava GPMS0991L and M. esculenta Crantz cv. pink cassava BRA117315, were used as research materials. Results showed that sugar cassava GPMS0991L was rich in glucose and fructose, whereas pink cassava BRA117315 was rich in starch and sucrose. Metabolomic and transcriptomic analysis indicated that sucrose and starch metabolism had significantly changing metabolites enrichment and the highest degree of differential expression genes, respectively. Sugar transport in storage roots may contribute to the activities of sugar, which will eventually be exported to transporters (SWEETs), such as (MeSWEET1a, MeSWEET2b, MeSWEET4, MeSWEET5, MeSWEET10b, and MeSWEET17c), which transport hexose to plant cells. The expression level of genes involved in starch biosynthesis and metabolism were altered, which may result in starch accumulation. These results provide a theoretical basis for sugar transport and starch accumulation and may be useful in improving the quality of tuberous crops and increasing yield.

Histone deacetylase 9 regulates disease resistance through fine-tuning histone deacetylation of melatonin biosynthetic genes and melatonin accumulation in cassava

Melatonin participates in plant growth and development and biotic and abiotic stress responses. Histone acetylation regulates many plant biological processes via transcriptional reprogramming. However, the direct relationship between melatonin and histone acetylation in plant disease resistance remains unclear. In this study, we identified cassava bacterial blight (CBB) responsive histone deacetylase 9 (HDA9), which negatively regulated disease resistance to CBB by reducing melatonin content. In addition, exogenous melatonin alleviated disease sensitivity of MeHDA9 overexpressed plants to CBB. Importantly, MeHDA9 inhibited the expression of melatonin biosynthetic genes through decreasing lysine 5 of histone 4 (H4K5) acetylation at the promoter regions of melatonin biosynthetic genes, thereby modulating melatonin accumulation in cassava. Furthermore, protein phosphatase 2C 12 (MePP2C12) interacted with MeHDA9 in vivo and in vitro, and it was involved in MeHDA9-mediated disease resistance via melatonin biosynthetic pathway. In summary, this study highlights the direct interaction between histone deacetylation and melatonin biosynthetic genes in cassava disease resistance via histone deacetylation, providing new insights into the genetic improvement of disease resistance via epigenetic regulation of melatonin level in tropical crops.

First Report of Macrophomina phaseolina Causing Leaf Blight of Cassava in China

Cassava (Manihot esculenta Crantz) is an important tropical and subtropical crop that feeds nearly 600 million people worldwide and is widely grown in Hainan Province, China (Vanderschuren et al., 2014). In November 2021, leaf blight symptoms were observed on South China 6 (SC6) cassava plants in Haikou City, Hainan Province, China. The disease was presented in almost every cassava plant we observed. The rotten leaves were shown to be infected but not the root or stem. The lesions started on the plant's lower leaves and gradually developed on the upper leaves of the entire cassava plant. The infected leaves gradually withered. Microscopic observation showed that the infected leaves exhibited necrotic lesions with pycnidial structures all over their surface. Diseased leaf segments (4 × 4 mm) were disinfected for 30 seconds with sodium hypochlorite 1% solution and then rinsed with sterile water for 30 seconds before being placed on potato dextrose agar (PDA) medium. Plates were incubated at 28°C in complete darkness. Marginal hyphae were picked and placed on a new PDA medium, and pure cultures were obtained after multiple transfers. The hyphae started white and gradually changed to a fluffy black-gray color as it grew on the PDA. Microscopic observation showed that there were a large number of ellipsoidal microsclerotia between the hyphae. Microsclerotia were sub fusiform, and hyaline, with a length of about 40 μm. The ribosomal internal transcribed spacer (ITS) region, ribosomal small subunit (SSU) region, and ribosomal large subunit (LSU) region of the isolate were amplified and sequenced using primers ITS1 and ITS4, NS1 and NS4 (White et al., 1990), and LROR and LR5 (Moriya et al., 2005), respectively. The obtained ITS (GenBank accession no. OP185242), SSU (GenBank accession no. OQ165195), and LSU (GenBank accession no. OQ118350.1) had 99.8% (100% coverage), 100% (100% coverage), and 100% (100% coverage) identities with the references ITS (GenBank accession no. KF951698), SSU (GenBank accession no. KF766281.1), and LSU (GenBank accession no. KF766364.1) in Macrophomina phaseolina, respectively. A phylogenetic tree was constructed with software MEGA7 using the maximum likelihood method, showing that the isolate was grouped in the same clade as M. phaseolina. To prove Koch's postulates, five healthy SC6 cassava plants (2-month-old) with 4-6 leaves were wounded with a small pin and inoculated with PDA blocks (3 × 3 mm) excised from the margin of a 7-day-cultured colony (Hu et al., 2022). Healthy plants treated with sterile PDA plugs served as controls. All plants were grown at 25°C with a 12-h light/dark rotation. After 7 days, typical blight symptoms developed on leaves inoculated with M. phaseolina, but not on the controls. The fungus was isolated from infected leaves. Based on molecular identification, M. phaseolina was re-isolated from leaves with leaf blight symptoms. Macrophomina is typically found to cause root and lower stem rot on cassava in Africa (Msikita et al., 1998). To the best of our knowledge, this is the first report of M. phaseolina causing leaf blight on cassava in China. Our finding provides a foundation to management of this disease.

Analysis of the molecular and biochemical mechanisms involved in the symbiotic relationship between Arbuscular mycorrhiza fungi and Manihot esculenta Crantz

INTRODUCTION

Plants and arbuscular mycorrhizal fungi (AMF) mutualistic interactions are essential for sustainable agriculture production. Although it is shown that AMF inoculation improves cassava physiological performances and yield traits, the molecular mechanisms involved in AM symbiosis remain largely unknown. Herein, we integrated metabolomics and transcriptomics analyses of symbiotic (Ri) and asymbiotic (CK) cassava roots and explored AM-induced biochemical and transcriptional changes.

RESULTS

Three weeks (3w) after AMF inoculations, proliferating fungal hyphae were observable, and plant height and root length were significantly increased. In total, we identified 1,016 metabolites, of which 25 were differentially accumulated (DAMs) at 3w. The most highly induced metabolites were 5-aminolevulinic acid, L-glutamic acid, and lysoPC 18:2. Transcriptome analysis identified 693 and 6,481 differentially expressed genes (DEGs) in the comparison between CK (3w) against Ri at 3w and 6w, respectively. Functional enrichment analyses of DAMs and DEGs unveiled transport, amino acids and sugar metabolisms, biosynthesis of secondary metabolites, plant hormone signal transduction, phenylpropanoid biosynthesis, and plant-pathogen interactions as the most differentially regulated pathways. Potential candidate genes, including nitrogen and phosphate transporters, transcription factors, phytohormone, sugar metabolism-related, and SYM (symbiosis) signaling pathway-related, were identified for future functional studies.

DISCUSSION

Our results provide molecular insights into AM symbiosis and valuable resources for improving cassava production.

Reactive oxygen species turnover, phenolics metabolism, and some key gene expressions modulate postharvest physiological deterioration in cassava tubers

Rapid postharvest physiological deterioration (PPD) in cassava (Manihot esculenta Crantz) tuber is a significant concern during storage. The freshly harvested tubers start spoiling within 24 to 72 h. Accumulation of H2O2 is one of the earliest biochemical events that occurred during PPD, which was detected using the 3,3 diaminobenzidine (DAB) in two contrast cassava genotypes, MNP Local A (29-57 μg g-1) and Sree Prakash (64-141 μg g-1). Accumulating the fluorescence hydroxycoumarin compounds emitted by the cassava tubers observed under an ultraviolet (UV) lamp showed significant variations at 0, 3, 6, 9, 12, and 15 days of storage. The total phenolics and carotenoids significantly and negatively correlated with PPD progression; however, the anthocyanin and flavonoids positively correlated with the PPD-anchored ROS accumulation. The primary compound, Phthalic acid, di(2-propylpentyl) ester, was identified in both the cassava tubers, Sree Prakash (57.21 and 35.21%), and MNP Local A (75.58 and 60.21%) at 0, and 72 h of PPD, respectively. The expression of PPD-associated genes APX-2, APX-3, PAL, and AP was higher at 6-12 days of PPD, which signified the synthesis of ROS turnover and phenylpropanoid biosynthesis. A significant, strong, and positive correlation was established between the secondary metabolites and PPD signaling gene expression, which was inversely correlated with hydroxycoumarin and H2O2 accumulation. MNP Local A tubers exhibited longer storage life of 15 days with a low PPD score, higher metabolites synthesis, and gene expression. The PPD-resistant lines may be used to augment cassava breeding strategies for large-scale commercial and industrial use.

Effects of different starch diets on growth performance, intestinal health and faecal microbiota of growing pigs

This experiment was conducted to investigate the effects of different starch source diets on growth performance, intestinal health, and, microbiota of growing pigs. Eighteen healthy "Duroc × Landrace × Yorkshire" pigs (50 ± 0.61 kg, Castrated boar) were randomly divided into three groups with six replicates and one pig per replicate. The pigs in the three treatments were fed diets prepared with cassava flour (CF), rice bran (RB) and sorghum flour (SF), respectively, and the nutritional levels of the three treatments were the same. The experiment lasted for 28 days. The results showed that pigs in the RB group had significantly increased average daily gain (ADG, p < 0.05) compared with pigs in CF and SF groups. Compared with pigs in the CF group, the final body weight (FBW) of growing pigs in the RB group was increased and the ratio of feed to gain (F: G) was decreased (p < 0.05). There was no significant difference between FBW and F: G between the SF group and the other two groups. Compared with the CF group, the RB group significantly increased the jejunum amylase activity (p < 0.05), and there was no significant difference between the SF group and the other two groups. Compared with growing pigs in the CF group and SF group, the duodenal villus height and villus height/crypt depth ratio of growing pigs in the RB group were significantly increased (p < 0.05). The concentrations of acetic acid, propionic acid, and total VFA in the colon and caecum of piglets in the SF group were significantly increased (p < 0.05) compared to piglets in CF and RB groups, and there was no significant difference between the CF group and RB group. Compared with the RB group, caecal butyric acid concentration was significantly increased in SF and CF groups (p < 0.05). Seven dominant phyla were identified at the phylum level, among which Firmicutes, Bacteroidota and Spirochaetota were dominant phyla, accounting for 74.18%, 14.87% and 6.56% of the RB group respectively. Cassava flour group accounted for 80.22%, 9.64% and 3.71%; Accounting for 65.33%, 17.34% and 13.07% of the SF group. Through the comparative analysis of microbial differences among the treatment groups, it was found that at the phylum level, compared with the SF group, the abundance of Synergistota in the diet of the CF group and the diet of the RB group was significantly increased (p < 0.05). The abundance decreased significantly (p < 0.05). The quantity of Desulfobacterota in the RB group was significantly higher than that in the CF group (p < 0.05). In conclusion, compared with sorghum starch and cassava starch, RB starch can improve the activity of digestive enzymes and villus height in the small intestine of growing pigs and promote the growth of pigs by protecting the intestinal health of growing pigs.

Bread Products from Blends of African Climate Resilient Crops: Baking Quality, Sensory Profile and Consumers' Perception

With food insecurity rising dramatically in Sub-Saharan Africa, promoting the use of sorghum, cowpea and cassava flours in staple food such as bread may reduce wheat imports and stimulate the local economy through new value chains. However, studies addressing the technological functionality of blends of these crops and the sensory properties of the obtained breads are scarce. In this study, cowpea varieties (i.e., Glenda and Bechuana), dry-heating of cowpea flour and cowpea to sorghum ratio were studied for their effects on the physical and sensory properties of breads made from flour blends. Increasing cowpea Glenda flour addition from 9 to 27% (in place of sorghum) significantly improved bread specific volume and crumb texture in terms of instrumental hardness and cohesiveness. These improvements were explained by higher water binding, starch gelatinization temperatures and starch granule integrity during pasting of cowpea compared to sorghum and cassava. Differences in physicochemical properties among cowpea flours did not significantly affect bread properties and texture sensory attributes. However, cowpea variety and dry-heating significantly affected flavour attributes (i.e., beany, yeasty and ryebread). Consumer tests indicated that composite breads could be significantly distinguished for most of the sensory attributes compared to commercial wholemeal wheat bread. Nevertheless, the majority of consumers scored the composite breads from neutral to positive with regard to liking. Using these composite doughs, chapati were produced in Uganda by street vendors and tin breads by local bakeries, demonstrating the practical relevance of the study and the potential impact for the local situation. Overall, this study shows that sorghum, cowpea and cassava flour blends can be used for commercial bread-type applications instead of wheat in Sub-Saharan Africa.

Utilization of Local Microorganisms as Bioactivators to Produce Organic Fertilizers and Analysis of Molecular Bacterial Diversity

<b>Background and Objective:</b> Local micro organism (LMO) is the result of the fermentation of various mixtures of organic matter. One of the organic materials used, based on the local wisdom of West Sumatra, is tapai (fermented Cassava), which is used as a bio activator in the manufacture of organic fertilizer. The research aims to produce organic fertilizers that meet national quality standards in terms of the physical and chemical quality of fertilizers as well as to determine the diversity of bacteria in bio activators through next-generation sequencing analysis. <b>Materials and Methods:</b> The organic ingredients for bio activators, cow feces as basic fertilizer ingredients, materials for analyzing bacterial diversity, LMO gDNA was extracted using ZymoBIOMICS DNA Miniprep Kit DNA and sequenced using Oxford Nanopore Technology. <b>Results:</b> On a scale of 1-3, the physical quality of organic fertilizers had an average value of 2.58 for smell, 2.83 for texture and 2.58 for color. The chemical quality of organic fertilizers is C-organic (23.56%), nitrogen (1.60%), carbon and nitrogen ratio (14.75%), phosphate (0.47%) and potassium (0.64%). The results of the analysis of bacteria on the bioactivator consisted of 7 phyla, 9 families, 45 genres and 297 species. The most common species is <i>Lentilactobacillus hilgardii</i> (62%). <b>Conclusion:</b> The organic fertilizer produced using the mole tapai bio activator complies with Indonesian national standard 19-7030-2004 based on physical and chemical parameters. The type of bacteria that dominates the bioactivator is the lactic acid bacteria group, which reaches 90%.

MePAL6 regulates lignin accumulation to shape cassava resistance against two-spotted spider mite

INTRODUCTION

The two-spotted spider mite (TSSM) is a devastating pest of cassava production in China. Lignin is considered as an important defensive barrier against pests and diseases, several genes participate in lignin biosynthesis, however, how these genes modulate lignin accumulation in cassava and shape TSSM-resistance is largely unknown.

METHODS

To fill this knowledge gap, while under TSSM infestation, the cassava lignin biosynthesis related genes were subjected to expression pattern analysis followed by family identification, and genes with significant induction were used for further function exploration.

RESULTS

Most genes involved in lignin biosynthesis were up-regulated when the mite-resistant cassava cultivars were infested by TSSM, noticeably, the MePAL gene presented the most vigorous induction among these genes. Therefore, we paid more attention to dissect the function of MePAL gene during cassava-TSSM interaction. Gene family identification showed that there are 6 MePAL members identified in cassava genome, further phylogenetic analysis, gene duplication, cis-elements and conserved motif prediction speculated that these genes may probably contribute to biotic stress responses in cassava. The transcription profile of the 6 MePAL genes in TSSM-resistant cassava cultivar SC9 indicated a universal up-regulation pattern. To further elucidate the potential correlation between MePAL expression and TSSM-resistance, the most strongly induced gene MePAL6 were silenced using virus-induced gene silencing (VIGS) assay, we found that silencing of MePAL6 in SC9 not only simultaneously suppressed the expression of other lignin biosynthesis genes such as 4-coumarate--CoA ligase (4CL), hydroxycinnamoyltransferase (HCT) and cinnamoyl-CoA reductase (CCR), but also resulted in decrease of lignin content. Ultimately, the suppression of MePAL6 in SC9 can lead to significant deterioration of TSSM-resistance.

DISCUSSION

This study accurately identified MePAL6 as critical genes in conferring cassava resistance to TSSM, which could be considered as promising marker gene for evaluating cassava resistance to insect pest.

Single-cell transcriptome sequencing atlas of cassava tuberous root

INTRODUCTION

Single-cell transcriptome sequencing (ScRNA-seq) has emerged as an effective method for examining cell differentiation and development. In non-model plants, it hasn't been employed very much, especially in sink organs that are abundant in secondary metabolites.

RESULTS

In this study, we sequenced the single-cell transcriptomes at two developmental phases of cassava tuberous roots using the technology known as 10x Genomics (S1, S2). In total, 14,566 cells were grouped into 15 different cell types, primarily based on the marker genes of model plants known to exist. In the pseudotime study, the cell differentiation trajectory was defined, and the difference in gene expression between the two stages on the pseudotime axis was compared. The differentiation process of the vascular tissue and cerebral tissue was identified by the trajectory. We discovered the rare cell type known as the casparian strip via the use of up-regulated genes and pseudotime analysis, and we explained how it differentiates from endodermis. The successful creation of a protoplast isolation technique for organs rich in starch was also described in our study.

DISCUSSION

Together, we created the first high-resolution single-cell transcriptome atlas of cassava tuberous roots, which made significant advancements in our understanding of how these roots differentiate and develop.

Genome-wide identification, expression profiling, and functional analysis of ammonium transporter 2 (AMT2) gene family in cassava (Manihot esculenta crantz)

Background: Nitrogen (N), absorbed primarily as ammonium (NH₄ ⁺) from soil by plant, is a necessary macronutrient in plant growth and development. Ammonium transporter (AMT) plays a vital role in the absorption and transport of ammonium (NH₄ ⁺). Cassava (Manihot esculenta Crantz) has a strong adaptability to nitrogen deprivation. However, little is known about the functions of ammonium transporter AMT2 in cassava. Methods: The cassava AMT2-type genes were identified and their characteristics were analyzed using bioinformatic techniques. The spatial expression patterns were analyzed based on the public RNA-seq data and their expression profiles under low ammonium treatment were studied using Real-time quantitative PCR (RT-qPCR) method. The cassava AMT2 genes were transformed into yeast mutant strain TM31019b by PEG/LiAc method to investigate their functions. Results: Seven AMT2-type genes (MeAMT2.1-2.7) were identified in cassava and they were distributed on 6 chromosomes and included two segmental duplication events (MeAMT2.2/MeAMT2.4 and MeAMT2.3/MeAMT2.5). Based on their amino acid sequences, seven MeAMT2 were further divided into four subgroups, and each subgroup contained similar motif constitution and protein structure. Synteny analysis showed that two and four MeAMT2 genes in cassava were collinear with those in the Arabidopsis and soybean genomes, respectively. Sixteen types of cis-elements were identified in the MeAMT2 promoters, and they were related to light-, hormone-, stress-, and plant growth and development-responsive elements, respectively. Most of the MeAMT2 genes displayed tissue-specific expression patterns according to the RNA-seq data, of them, three MeAMT2 (MeAMT2.3, MeAMT2.5, and MeATM2.6) expressions were up-regulated under ammonium deficiency. Complementation experiments showed that yeast mutant strain TM31019b transformed with MeAMT2.3, MeAMT2.5, or MeATM2.6 grew better than untransgenic yeast cells under ammonium deficiency, suggesting that MeAMT2.3, MeAMT2.5, and MeATM2.6 might be the main contributors in response to ammonium deficiency in cassava. Conclusion: This study provides a basis for further study of nitrogen efficient utilization in cassava.

Cassava (Manihot esculenta Crantz): A Systematic Review for the Pharmacological Activities, Traditional Uses, Nutritional Values, and Phytochemistry

Cassava (Manihot esculenta Crantz) is considered one of the essential tuber crops, serving as a dietary staple food for various populations. This systematic review provides a comprehensive summary of the nutritional and therapeutic properties of cassava, which is an important dietary staple and traditional medicine. The review aims to evaluate and summarize the phytochemical components of cassava and their association with pharmacological activities, traditional uses, and nutritional importance in global food crises. To collect all relevant information, electronic databases; Cochrane Library, PubMed, Scopus, Web of Science, Google Scholar, and Preprint Platforms were searched for studies on cassava from inception until October 2022. A total of 1582 studies were screened, while only 34 were included in this review. The results of the review indicate that cassava has diverse pharmacological activities, including anti-bacterial, anti-cancer, anti-diabetic, anti-diarrheal, anti-inflammatory, hypocholesterolemic effects, and wound healing properties. However, more studies that aim to isolate the phytochemicals in cassava extracts and evaluate their pharmacological property are necessary to further validate their medical and nutritional values.

Comparative Transcriptome Profiling of Cassava Tuberous Roots in Response to Postharvest Physiological Deterioration

Cassava is one of the most versatile tuberous-root crops on Earth. However, the postharvest storage properties of cassava tuberous root mean that it is perishable through a process known as postharvest physiological deterioration (PPD), which seriously affects its starch quality. Therefore, a comprehensive understanding of the transcriptional regulatory activity of cassava against the PPD response is necessary in order to extract key molecular mechanisms related to PPD tolerance. In this study, we found that RYG1 tuberous roots showed delayed PPD compared to those of SC8. In addition, RYG1 roots maintained a more stable cell wall structure after storage than those of SC8. The transcriptome changes in tuberous roots were analyzed for both RYG1 and SC8 after 21 days of storage (SR and SS) compared to fresh (FR and FS) by the RNA-Seq method. The total number of differentially expressed genes (DEGs) in the various comparisons of these four samples ranged from 68 to 3847. Of these, a total of 2008 co-DEGs in SR vs. SS were shared by either SR vs. FR or SS vs. FS. GO and KEGG enrichment analysis revealed that upregulated co-DEGs in SR vs. SS were mainly enriched in photosynthesis, protein processing, hormone and cutin, suberine and wax biosynthesis. By contrast, the downregulated co-DEGs were mainly related to cell wall organization, starch and sucrose metabolism, galactose metabolism, phenylpropanoid biosynthesis, diterpenoid biosynthesis, cysteine and methionine metabolism and flavonoid biosynthesis. The protein-protein interaction (PPI) networks of the co-DEGs showed a complex interaction of genes in different pathways, and 16 hub genes were characterized to have a degree in excess of 15, among which eight genes were associated with photosynthesis. These results provide new information for the study of cassava resistance to PPD and lay a foundation for the further molecular breeding of storage-tolerant cassava varieties.

A promoter toolbox for tissue-specific expression supporting translational research in cassava (Manihot esculenta)

There is an urgent need to stimulate agricultural output in many tropical and subtropical countries of the world to combat hunger and malnutrition. The starchy crop cassava (Manihot esculenta), growing even under sub-optimal conditions, is a key staple food in these regions, providing millions of people with food. Cassava biotechnology is an important technique benefiting agricultural progress, but successful implementation of many biotechnological concepts depends on the availability of the right spatiotemporal expression tools. Yet, well-characterized cassava promoters are scarce in the public domain. In this study, we investigate the promoter activity and tissue specificity of 24 different promoter elements in stably transformed cassava plants. We show that many of the investigated promoters, especially from other species, have surprisingly low activity and/or tissue specificity, but feature several promoter sequences that can drive tissue-specific expression in either autotrophic-, transport- or storage tissues. We especially highlight pAtCAB1, pMePsbR, and pSlRBCS2 as strong and specific source promoters, pAtSUC2, pMeSWEET1-like, and pMeSUS1 as valuable tools for phloem and phloem parenchyma expression, and pStB33, pMeGPT, pStGBSS1, as well as pStPatatin Class I, as strong and specific promoters for heterotrophic storage tissues. We hope that the provided information and sequences prove valuable to the cassava community by contributing to the successful implementation of biotechnological concepts aimed at the improvement of cassava nutritional value and productivity.

Flour on Gluten-Free Muffins from Different Edible Cassava Varieties in Thailand

In Thailand new edible cassava varieties have been developed to be used in the food industry. The aim of this research was to analyze the difference between flour from three cassava varieties and to evaluate the suitability and quality of flour for gluten-free muffins. The physico-chemical properties of flour from three varieties were studied. The results showed the moisture content of flour was between 10.65 ± 0.01 and 10.85 ± 0.45%. Total protein content was highly significant with a difference of 1.97 ± 0.00%, 2.15 ± 0.01%, and 2.18 ± 0.01%, respectively. Moreover, ash and fat in each flour were highly significant. Amylose content was 19.93 ± 0.47%, and the viscosity was 6286.00 ± 1.52 mPa.s. The color of flour values of L* a* b* value was not statistically different in each variety of flour. Fourier transform infrared spectroscopy (FTIR) analysis was used for the biochemical change in flour. The PCA and cluster analysis results revealed that cassava flour from Pirun 6 was different from Pirun 2 and Pirun 4. After that, the test using selected cassava flour from Pirun 6 to test the physical properties and sensory attributes of gluten-free muffins compared with wheat flour found that gluten-free muffins were overall better than basic muffins.

Agrobacterium-mediated Genetic Transformation of Cassava

The storage root crop cassava (Manihot esculenta Crantz) is predicted to remain central to future food and economic security for smallholder farming households and agricultural output in the tropics. Genetic improvement of cassava is required to meet changing farmer and consumer needs, evolving pests and diseases, and challenges presented by climate change. Transgenic and genome editing technologies offer significant potential for introducing desired traits into farmer-preferred varieties and breeding lines, and for studying the biology of this under-investigated crop species. A bottleneck in implementing genetic modification in this species has been access to robust methods for transformation of cassava cultivars and landraces. In this article, we provide a detailed protocol for Agrobacterium-mediated transformation of cassava and regeneration of genetically modified plants. Basic Protocol 1 describes how to establish and micropropagate in vitro cassava plantlets, and Alternate Protocol 1 details how to establish in vitro cultures from field or greenhouse cuttings. Basic Protocol 2 describes all steps necessary for genetic transformation in the model variety 60444, and Alternate Protocol 2 provides details for modifying this method for use with other cultivars. Finally, Basic Protocol 3 describes how to establish plants produced via Basic Protocol 2 and Alternate Protocol 2 in soil in a greenhouse. These methods have proven applications across more than a dozen genotypes and are capable of producing transgenic and gene-edited plants for experimental purposes, for testing under greenhouse and field conditions, and for development of plants suitable for subsequent regulatory approval and product deployment. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Establishment and propagation of in vitro cassava plantlets Alternate Protocol 1: Establishment of in vitro plants from field or greenhouse plants Basic Protocol 2: Genetic transformation of cassava variety 60444 Alternate Protocol 2: Genetic transformation of additional cultivars Basic Protocol 3: Establishment and growth of plants in the greenhouse.

Utility of Ugandan genomic selection cassava breeding populations for prediction of cassava viral disease resistance and yield in West African clones

Cassava (Manihot esculenta Crantz) is a staple crop for ~800 million people in sub-Saharan Africa. Its production and productivity are being heavily affected by the two viral diseases: cassava brown streak disease (CBSD) and cassava mosaic disease (CMD), impacting greatly on edible root yield. CBSD is currently endemic to central, eastern and southern Africa, if not contained could spread to West Africa the largest cassava producer and consumer in the continent. Genomic selection (GS) has been implemented in Ugandan cassava breeding for accelerated development of virus resistant and high yielding clones. This study leveraged available GS training data in Uganda for pre-emptive CBSD breeding in W. Africa alongside CMD and fresh root yield (FRW). First, we tracked genetic gain through the current three cycles of GS in Uganda. The mean genomic estimated breeding values (GEBVs), indicated general progress from initial cycle zero (C0) to cycle one (C1) and cycle two (C2) for CBSD traits and yield except for CMD. Secondly, we used foliar data of both CBSD and CMD, as well as harvest root necrosis and yield data to perform cross-validation predictions. Cross-validation prediction accuracies of five GS models were tested for each of the three GS cycles and West African (WA) germplasm as a test set. In all cases, cross-validation prediction accuracies were low to moderate, ranging from -0.16 to 0.68 for CBSD traits, -0.27 to 0.57 for CMD and -0.22 to 0.41 for fresh root weight (FRW). Overall, the highest prediction accuracies were recorded in C0 for all traits tested across models and the best performing model in cross-validation was G-BLUP. Lastly, we tested the predictive ability of the Ugandan training sets to predict CBSD in W. African clones. In general, the Ugandan training sets had low prediction accuracies for all traits across models in West African germplasm, varying from -0.18 to 0.1. Based on the findings of this study, the cassava breeding program in Uganda has made progress through application of GS for most target traits, but the utility of the training population for pre-emptive breeding in WA is limiting. In this case, efforts should be devoted to sharing Ugandan germplasm that possess resistance with the W. African breeding programs for hybridization to fully enable deployment of genomic selection as a pre-emptive CBSD breeding strategy in W. Africa.

Recent Developments in Cassava (Manihot esculenta) Based Biocomposites and Their Potential Industrial Applications: A Comprehensive Review

The rapid use of petroleum resources coupled with increased awareness of global environmental problems associated with the use of petroleum-based plastics is a major driving force in the acceptance of natural fibers and biopolymers as green materials. Because of their environmentally friendly and sustainable nature, natural fibers and biopolymers have gained significant attention from scientists and industries. Cassava (Manihot esculenta) is a plant that has various purposes for use. It is the primary source of food in many countries and is also used in the production of biocomposites, biopolymers, and biofibers. Starch from cassava can be plasticized, reinforced with fibers, or blended with other polymers to strengthen their properties. Besides that, it is currently used as a raw material for bioethanol and renewable energy production. This comprehensive review paper explains the latest developments in bioethanol compounds from cassava and gives a detailed report on macro and nano-sized cassava fibers and starch, and their fabrication as blend polymers, biocomposites, and hybrid composites. The review also highlights the potential utilization of cassava fibers and biopolymers for industrial applications such as food, bioenergy, packaging, automotive, and others.

Genome-wide identification and expression of TIFY family in cassava (Manihot esculenta Crantz)

Plant-specific TIFY [TIF(F/Y)XG] proteins serve important roles in the regulation of plant stress responses. This family encodes four subfamilies of proteins, JAZ (JASMONATE ZIM-domain), PPD (PEAPOD), ZML (Zinc-finger Inflorescence-like), and TIFY. In this work, a total of 16 JAZ, 3 PPD, 7 ZML, and 2 TIFY genes were found in cassava (Manihot esculenta Crantz) at the genome-wide level. The phylogenetics, exon-intron structure, motif organization, and conserved domains of these genes were analyzed to characterize the members of the JAZ, PPD, and ZML subfamilies. Chromosome location and synteny analyses revealed that 26 JAZ, PPD, and ZML genes were irregularly distributed across 14 of the 18 chromosomes, and 18 gene pairs were implicated in large-scale interchromosomal segmental duplication events. In addition, JAZ, PPD, and ZML gene synteny comparisons between cassava and three other plant species (Arabidopsis, Populus trichocarpa, and rice) uncovered vital information about their likely evolution. The prediction of protein interaction network and cis-acting elements reveal the function of JAZ, PPD, and ZML genes. Subsequently, expression patterns of JAZ, PPD, and ZML genes were validated by qRT-PCR as being expressed in response to osmotic, salt, and cadmium stress. Moreover, almost all JAZ subfamily genes were responsive to jasmonic acid (JA) treatment. In particular, MeJAZ1, MeJAZ13, and MeJAZ14, were highly up-regulated by three treatments, and these genes may deserve further study. This comprehensive study lays the groundwork for future research into TIFY family genes in cassava and may be valuable for genetic improvement of cassava and other related species.