Tropical Strains Research Articles

Fatty Acid Profiling of Tropical Microalgae and Cyanobacteria Strains Isolated From Southwest Indian Ocean Islands

Tropical microalgae and cyanobacteria have natural potential virtues that can be used in a wide range of bioproducts. Indeed, they represent a large biodiversity and benefit from favorable environmental conditions. In this context, 27 isolated marine tropical strains have been studied for their total lipid content, lipid class’s distribution and fatty acids composition. Their potential use for applications in the field of biodiesel and nutritional products has been evaluated by the determination of various parameters estimated in relation to the carbon chain size and the amount and/or position of double bonds in fatty acids (as example, the cetane number, the iodine value, the polyunsaturated/saturated acids ratio, the omega 6 and 3 ratio (n6/n3)). The dinoflagellates Prorocentrum lima and Amphidinium massartii, and the cyanobacteria Leptolyngbya sp. RS01 have good characteristics for biodiesel production whereas Spirulina sp. has a good profile of fatty acids for nutritional application.

Effects of temperature on extracellular hydrolase enzymes from soil microfungi

Soil microbes play important roles in global carbon and nutrient cycling. Soil microfungi are generally amongst the most important contributors. They produce various extracellular hydrolase enzymes that break down the complex organic molecules in the soil into simpler form. In this study, we investigated patterns of amylase and cellulase (which are responsible for breaking down starch and cellulose, respectively) relative activity (RA) on solid media at different culture temperatures in fungal strains from Arctic, Antarctic and tropical soils. Fungal isolates from all three regions were inoculated onto R2A media supplemented with starch for amylase and carboxymethylcellulose and trypan blue for cellulase screening. The isolates were then incubated at 4, 10, 15, 20, 25, 30, 35 and 40 °C and examined for activity after 5 and 10 days, for tropical and polar isolates, respectively. The data obtained indicate that the polar fungal strains exhibited similar patterns of amylase and cellulase RA. Both Arctic and Antarctic fungi showed highest RA for amylase and cellulase at 35 °C, while colony growth was maximised at 15 °C. Colony growth and RA of the polar isolates were negatively correlated suggesting that, as temperatures increase, the cells become stressed and have fewer resources available to invest in growth. Unlike polar isolates, tropical isolates did not exhibit any trend of colony growth with temperature, rather having idiosyncratic patterns in each isolate. The low enzyme production and RA levels in the tropical strains may suggest both a low ability to respond to temperature variation in their natural thermally stable tropical habitats, as well as a level of thermal stress limiting their enzyme production ability.

A highly efficient Agrobacterium tumefaciens-mediated transformation system for the postharvest pathogen Penicillium digitatum using DsRed and GFP to visualize citrus host colonization

Penicillium digitatum is a major postharvest pathogen of citrus crops. This fungus broadly spreads worldwide and causes green mold disease, which results in severe losses for citrus production. Understanding of the citrus infection by P. digitatum may help develop effective strategies for controlling this pathogen. In this study, we have characterized a virulent strain of P. digitatum isolated in Vietnam and established a highly efficient Agrobacterium tumefaciens-mediated transformation (ATMT) system for this fungal strain with two newly constructed binary vectors. These binary vectors harbor dominant selectable markers for hygromycin or nourseothricin resistance, and expression cassettes for the red fluorescent protein (DsRed) or the green fluorescent protein (GFP), respectively. Using the established ATMT system, the transformation efficiency of the Vietnamese strain could reach a very high yield of 1240±165 transformants per 106 spores. Interestingly, we found that GFP is much better than DsRed for in situ visualization of citrus fruit colonization by the fungus. Additionally, we showed that the transformation system can also be used to generate T-DNA insertion mutants for screening non-pathogenic or less virulent strains. Our work provides a new platform including a virulent tropical strain of P. digitatum, an optimized ATMT method and two newly constructed binary vectors for investigation of the postharvest pathogen. This platform will help develop strategies to dissect molecular mechanisms of host-pathogen interactions in more detail as well as to identify potential genes of pathogenicity by either insertional mutagenesis or gene disruption in this important pathogenic fungus.

Exploring the metabolic and physiological diversity of native microalgal strains (Chlorophyta) isolated from tropical freshwater reservoirs

Microalgae have attracted interest as a potential feedstock for biodiesel and valuable co-products such as bioethanol and protein. However, production at a commercial scale is still costly in part due to a lack of knowledge of their biology which in turn limits our ability to increase their overall growth rate or alter their metabolism and composition through changes in culture conditions or genetic engineering. We therefore isolated ten strains of freshwater microalgae (Chlorophyta) and characterized them at the morphological, molecular and biochemical level under autotrophic conditions. Two Scenedesmus strains (BR003 and BR024) differed from others strains in respect to their fatty acid profile, with high levels of C16 and C18:1 and low levels of polyunsaturated fatty acids. Interestingly, Chlamydomonas sp. BR020 and Chlorella vulgaris BR017 showed high levels of α-linolenic acid (C18:3), while BR017 also exhibited higher protein levels (14% of total dry weight), suggesting that these may be interesting strains to be used within the biorefinery concept. Furthermore, Monoraphidium sp. BR023 showed higher lipid content (29% of total dry weight), and transesterifiable fatty acid production (43.2μgmg−1 dry weight) and lower starch levels (164μmolmg−1 dry weight) while Chlamydomonas sp. BR020 exhibited the opposite trend. The results suggest that Scenedesmus bajacalifornicus BR024, Selenastrum capricornutum BR009 and Scenedesmus obliquus BR003 represent potential strains for biomass and biodiesel production, presenting 1.81, 1.73 and 2.14mgmL−1 dry weight of biomass, respectively, and 21.6, 16.4 and 17% of total dry weight of lipid, respectively. Additionally, the two Scenedesmus species showed the highest lipid productivity (23mgL−1d−1 and 24mgL−1d−1). Overall we were able to access a new source of microalgal biodiversity and perform a robust characterization of native tropical microalgae strains leading to the identification of strains with high potential for biotechnological applications.

Enzymatic Hydrolysis of Black Liquor Xylan by a Novel Xylose-Tolerant, Thermostable β-Xylosidase from a Tropical Strain of Aureobasidium pullulans CBS 135684.

From three cell-associated β-xylosidases produced by Aureobasidium pullulans CBS 135684, the principal enzyme was enriched to apparent homogeneity and found to be active at high temperatures (60-70°C) over a pH range of 5-9 with a specific activity of 163.3units (U) mg-1. The enzyme was thermostable, retaining over 80% of its initial activity after a 12-h incubation at 60°C, with half-lives of 38, 22, and 10h at 60, 65, and 70°C, respectively. Moreover, it was tolerant to xylose inhibition with a K i value of 18mM. The K m and V max values against p-nitrophenyl-β-d-xylopyranoside were 5.57±0.27mM and 137.0±4.8μmolmin-1mg-1 protein, respectively. When combining this β-xylosidase with xylanase from the same A. pullulans strain, the rate of black liquor xylan hydrolysis was significantly improved by up to 1.6-fold. The maximum xylose yield (0.812±0.015gg-1 dry weight) was obtained from a reaction mixture containing 10% (w/v) black liquor xylan, 6Ug-1 β-xylosidase and 16Ug-1 xylanase after incubation for 4h at 70°C and pH 6.0.

Fatty acids profile and nutritional composition of two tropical diatoms from the Costa Rican Pacific Coast

Microalgae represent an important nutritional source for diverse organisms, therefore, their nutritional value, and more specifically, total lipid and fatty acid contents, must be considered. This study evaluated the nutritional contents and potential growth under controlled conditions of Nitzschia sp. and Chaetoceros sp. Tropical microalgae, isolated from the Gulf of Nicoya, Costa Rica. In both strains, the nutritional composition and the fatty acid profile were evaluated in exponential and stationary phases. With regards to fatty acids, v sp. had more Eicosapentaenoic Acid (EPA) in both the exponential (32.80%) and stationary (27.20%) phases. The results in growth rate, production and biochemical composition indicated two tropical microalgae strains suitable for cultivation under controlled conditions. The studies of the phytoplankton in this geographical area is highly relevant because of its importance in the primary production of nutrients and the importance of finding sources of fatty acids such as the EPA.

Effect of elevated temperature on the physiological responses of marine Chlorella strains from different latitudes

The increased frequency of heat waves due to climate change poses a threat to all organisms. Microalgae are the basis of aquatic food webs, and high temperatures have significant impacts on their adaptation and survival rates. Algae respond to environmental changes by modulating their photosynthetic rates and biochemical composition. This study aims to examine the effect of elevated temperature on similar taxa of marine Chlorella originating from different latitudes. Strains from the Antarctic, temperate zone, and the tropics were grown at various temperatures, ranging from 4 to 38, 18 to 38, and 28 to 40 °C, respectively. A pulse-amplitude modulated (PAM) fluorometer was used to assess their photosynthetic responses. Parameters including maximum quantum efficiency (F v/F m), relative electron transport rate (rETR), and light harvesting efficiency (α) were determined from the rapid light curves (RLCs). In addition, the composition of fatty acids was compared to evaluate changes induced by the temperature treatments. Increasing the temperature from 35 to 38 °C for both Antarctic and temperate strains and from 38 to 40 °C for the tropical strain resulted in severe inhibition of photosynthesis and suppressed growth. Although all the strains demonstrated the ability to recover from different stress levels, the tropical strain was able to recover most rapidly while the Antarctic strain had the slowest recovery. The results underline that the thermal threshold for the analysed Chlorella strains temperature ranges between 38 and 40 °C. Furthermore, the analysed strains exhibited different trends in their response to elevated temperatures and recovery capabilities.

Use of Tropical Strains: Aspergillus vadensis and Aspergillus oryzae as Producers of α-Amylases in Biotechnological Practice

Use of Tropical Strains: Aspergillus vadensis and Aspergillus oryzae as Producers of α-Amylases in Biotechnological Practice

Phylogenies of symbiotic genes of Bradyrhizobium symbionts of legumes of economic and environmental importance in Brazil support the definition of the new symbiovars pachyrhizi and sojae

Bradyrhizobium comprises most tropical symbiotic nitrogen-fixing strains, but the correlation between symbiotic and core genes with host specificity is still unclear. In this study, the phylogenies of the nodY/K and nifH genes of 45 Bradyrhizobium strains isolated from legumes of economic and environmental importance in Brazil (Arachis hypogaea, Acacia auriculiformis, Glycine max, Lespedeza striata, Lupinus albus, Stylosanthes sp. and Vigna unguiculata) were compared to 16S rRNA gene phylogeny and genetic diversity by rep-PCR. In the 16S rRNA tree, strains were distributed into two superclades—B. japonicum and B. elkanii—with several strains being very similar within each clade. The rep-PCR analysis also revealed high intra-species diversity. Clustering of strains in the nodY/K and nifH trees was identical: 39 strains isolated from soybean grouped with Bradyrhizobium type species symbionts of soybean, whereas five others occupied isolated positions. Only one strain isolated from Stylosanthes sp. showed similar nodY/K and nifH sequences to soybean strains, and it also nodulated soybean. Twenty-one representative strains of the 16S rRNA phylogram were selected and taxonomically classified using a concatenated glnII-recA phylogeny; nodC sequences were also compared and revealed the same clusters as observed in the nodY/K and nifH phylograms. The analyses of symbiotic genes indicated that a large group of strains from the B. elkanii superclade comprised the novel symbiovar sojae, whereas for another group, including B. pachyrhizi, the symbiovar pachyrhizi could be proposed. Other potential new symbiovars were also detected. The co-evolution hypotheses is discussed and it is suggested that nodY/K analysis would be useful for investigating the symbiotic diversity of the genus Bradyrhizobium.

Development of a hydrolysis probe-based real-time assay for the detection of tropical strains of Fusarium oxysporum f. sp. cubense race 4.

Fusarium oxysporum f. sp. cubense (Foc) is one of the most important threats to global banana production. Strategies to control the pathogen are lacking, with plant resistance offering the only long-term solution, if sources of resistance are available. Prevention of introduction of Foc into disease-free areas thus remains a key strategy to continue sustainable banana production. In recent years, strains of Foc affecting Cavendish bananas have destroyed plantations in a number of countries in Asia and in the Middle East, and one African country. One vegetative compatibility group (VCG), 01213/16, is considered the major threat to bananas in tropical and subtropical climatic conditions. However, other genetically related VCGs, such as 0121, may potentially jeopardize banana cultures if they were introduced into disease-free areas. To prevent the introduction of these VCGs into disease-free Cavendish banana-growing countries, a real-time PCR test was developed to accurately detect both VCGs. A previously described putative virulence gene was used to develop a specific combination of hydrolysis probe/primers for the detection of tropical Foc race 4 strains. The real-time PCR parameters were optimized by following a statistical approach relying on orthogonal arrays and the Taguchi method in an attempt to enhance sensitivity and ensure high specificity of the assay. This study also assessed critical performance criteria, such as repeatability, reproducibility, robustness, and specificity, with a large including set of 136 F. oxysporum isolates, including 73 Foc pathogenic strains representing 24 VCGs. The validation data demonstrated that the new assay could be used for regulatory testing applications on banana plant material and can contribute to preventing the introduction and spread of Foc strains affecting Cavendish bananas in the tropics.

Digitonthophagus gazella auctorum: an unfortunate case of mistaken identity for a widely introduced species (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini).

At risk of committing entomological heresy, we question the identity of a dung-burying beetle species that originates from Africa and has been introduced first into Hawaii and subsequently to Australasia, North America, and South America (Fincher 1986; Edwards 2007; Noriega et al. 2010) for pasture improvement and biological control of dung-breeding flies (Waterhouse 1974; Bornemissza 1979). Under the name Onthophagus gazella (Fabricius 1787), it was the first species selected for introduction into Australia by the CSIRO Dung Beetle Project (Bornemissza 1976; Edwards 2007). Firstly, in 1968, a "tropical strain" was introduced from Hawaii where it had become established after introduction from Zimbabwe in 1957 (Markin & Yoshioka 1998). Later, after establishment of the CSIRO Dung Beetle Research Unit in Pretoria in 1970, a "cold" or "even rainfall strain" was introduced into Australia directly from South Africa (Bornemissza 1976) (even rainfall region = south coast of Eastern Cape). The species was subsequently introduced into the southern continental United States of America (Victoria County, Texas) from Hawaii (Montes de Oca & Halffter 1998) then elsewhere into southeastern and southwestern states from Hawaii and breeding colonies from Australia (Anderson & Loomis 1978). It has since expanded its range through Mexico, Central America, and the Caribbean to coastal Colombia (Kohlmann 1994; Noriega 2002; Noriega et al. 2006, 2011). Expansion of its range within central southern South America (Noriega et al. 2010) has been assisted by introductions into Brazil from the United States of America since the 1980s (Bianchin et al. 1998), and others into Venezuela and Chile (Vidaurre et al. 2008). More recently, it has been introduced into quarantine and field trials in New Zealand (Forgie et al. 2013) using individuals originating from the south coast of the Eastern Cape and Northwest Province of South Africa (S. Forgie, personal communication).

Production of γ-Decalactone by Yeast Strains under Different Conditions.

γ-Decalactone is a flavour compound that when obtained by biotechnological production using microorganisms is classified as natural. The aim of this study is to evaluate various conditions for γ-decalactone production by tropical yeast strains Yarrowia lipolytica CCMA 0242 and Lindnera saturnus CCMA 0243. The growth of and γ-decalactone production by Y. lipolytica CCMA 0242 were higher in castor oil than in glycerol. γ-Decalactone production in single batch or fed-batch fermentation did not differ significantly. The γ-decalactone production by L. saturnus CCMA 0243 was better at initial pH=5, while the production by Y. lipolytica CCMA 0242 was better at initial pH=6. The yeast L. saturnus CCMA 0243 produced more γ-decalactone than Y. lipolytica CCMA 0242 under the same fermentation conditions. The crude glycerol was not an alternative substrate for γ-decalactone production by Y. lipolytica CCMA 0242. Castor oil at volume fraction of 30% showed better results as a substrate. The strain L. saturnus CCMA 0243 showed better results of γ-decalactone production. This yeast species can be considered an alternative producer of γ-decalactone in biotechnological processes.

Partial Purification of α-amylase Expressed by a Tropical Mutant Strain of Aspergillus niger IFE 08

Partial Purification of α-amylase Expressed by a Tropical Mutant Strain of Aspergillus niger IFE 08

Allele genetypes and homology analysis of MSP-1 and CSP gene of Plasmodium vivax in Shandong Province

To analyze the genotypes and homology of MSP-1 and CSP gene of Plasmodium vivax in Shandong Province, so as to provide the evidence for case traceability. A total of 12 blood samples were collected from P. vivax-infected cases in Shandong Province in 2011. Parasite genomic DNA was extracted. Primers were designed according to MSP-1 and CSP gene sequences of P. vivax. Then Nested PCR, enzyme digestion, sequencing and sequence alignment, and homologous analysis were performed. The MSP-1 gene of all the 12 samples from P. vivax-infected cases were detected with a 470 bp PCR amplification band, and 350 bp and 120 bp enzyme digestion fragments, which were identified as type Sal-1. An analysis of phylogenetic tree of MSP-1 gene showed that the sequences of 9 indigenous case samples in Shandong Province were located in the same branch, one case sample infected from India was located in the same branch with India strains. All the 12 P. vivax-infected samples covered GDRA (D/A) GQPA sequences in CSP gene, which were identified as type PV-Ⅰ. Of the CSP gene among 12 P. vivax-infected samples, 10 samples of indigenous case in Shandong Province and one sample of the case infected in Guangdong Province were detected with both 560-840 bp and 150-230 bp PCR amplification bands, which were identified as temperate zone family strain of type PV-Ⅰ. However, one sample from the case infected in India was detected only with a 560-840 bp band, which was identified as tropical zone family strain of PV-Ⅰ. An analysis of phylogenetic tree of CSP gene showed that the sequences of 10 samples from the indigenous cases in Shandong Province and one sample from the case infected in Guangdong Province were located in the same branch, one sample from the case infected in India was located in the same branch with India and Indonesia strains. Of all the indigenous isolates in Shandong Province, MSP-1 gene is genotyped type Sal-1, CSP gene is genotyped temperate zone family strain of type PV-Ⅰ, with a high homology found among the indigenous isolates.

Partial purification of α-amylase expressed by a tropical mutant strain of Aspergillus flavus IFE 03

Partial purification of α-amylase expressed by a tropical mutant strain of Aspergillus flavus IFE 03

Asterionellopsis tropicalis (Bacillariophyceae): a new tropical species found in diatom accumulations.

The diatom Asterionellopsis glacialis sensu lato forms high-density patches in the surf zone of some sandy beaches worldwide and was until recently considered a cosmopolitan species. With the recent description of four cryptic species, the identity of specimens found in these accumulations remains uncertain. In this study, diatom patches were sampled from two sandy beaches of the Brazilian coast: one tropical (Futuro Beach, 3° S; 38° W) and one subtropical (Cassino Beach, 32° S; 52° W). Fine structure of frustules and the sequencing of three phylogenetic markers revealed the subtropical strains to be A.guyunusae and the tropical strains to be a new species, here described as Asterionellopsis tropicalis sp. nov. A.tropicalis was differentiated morphologically by the number of striae in 10μm at the foot pole and head (39-44; 38-45, respectively), from A.lenisilicea (46-55; 46-64), A.maritima (46-51; 46-60), and A.thurstonii (42-58; 55-70). The number of striae at the head region of the valvocopula (10μm) helped to distinguish A.tropicalis (56-62) from A.guyunusae (61-64), but A.tropicalis was morphologically undistinguishable from A.glacialis. The sequence divergence from other identified Asterionellopsis species was 13%-16% (Cox1), 11%-12% (5.8S + ITS2) and 2%-6% (RbcL), and A.tropicalis formed a distinct monophyletic clade with high support in all analyzed phylogenetic trees (single or multi-locus). This work will aid in the understanding of the ecological and physiological diversity of diatom patches that are key to the trophic webs of sandy beaches.

Physiological and transcriptional responses to inorganic nutrition in a tropical Pacific strain of Alexandrium minutum: Implications for the saxitoxin genes and toxin production

Saxitoxins (STXs) constitute a family of potent sodium channel blocking toxins, causative agents of paralytic shellfish poisoning (PSP), and are produced by several species of marine dinoflagellates and cyanobacteria. Two STX-core genes, sxtA and sxtG, have been well elucidated in Alexandrium but the expression of these genes under various nutritional modes in tropical species remains unclear. This study investigates the physiological responses of a tropical Pacific strain of Alexandrium minutum growing with nitrate or ammonium, and with various nitrogen to phosphorus (N:P) supply ratios. The transcriptional responses of the sxt genes were observed. Likewise, a putative sxtI encoding O-carbamoyltransferase (herein designated as AmsxtI) was recovered from the transcriptomic data, and its expression was investigated. The results revealed that the cellular toxin quota (Qt) was higher in P-depleted, nitrate-grown cultures. With cultures at similar N:P (<16), cells grown with excess ammonium showed a higher Qt than those grown with nitrate. sxtA1 was not expressed under any culture conditions, suggesting that this gene might not be involved in STX biosynthesis by this strain. Conversely, sxtA4 and sxtG showed positive correlations with Qt, and were up-regulated in P-depleted, nitrate-grown cultures and with excess ambient ammonium. On the other hand, AmsxtI was expressed only when induced by P-depletion, suggesting that this gene may play an important role in P-recycling metabolism, while simultaneously enhancing toxin production.

Variation in relapse frequency and the transmission potential of Plasmodium vivax malaria.

There is substantial variation in the relapse frequency of Plasmodium vivax malaria, with fast-relapsing strains in tropical areas, and slow-relapsing strains in temperate areas with seasonal transmission. We hypothesize that much of the phenotypic diversity in P. vivax relapses arises from selection of relapse frequency to optimize transmission potential in a given environment, in a process similar to the virulence trade-off hypothesis. We develop mathematical models of P. vivax transmission and calculate the basic reproduction number R0 to investigate how transmission potential varies with relapse frequency and seasonality. In tropical zones with year-round transmission, transmission potential is optimized at intermediate relapse frequencies of two to three months: slower-relapsing strains increase the opportunity for onward transmission to mosquitoes, but also increase the risk of being outcompeted by faster-relapsing strains. Seasonality is an important driver of relapse frequency for temperate strains, with the time to first relapse predicted to be six to nine months, coinciding with the duration between seasonal transmission peaks. We predict that there is a threshold degree of seasonality, below which fast-relapsing tropical strains are selected for, and above which slow-relapsing temperate strains dominate, providing an explanation for the observed global distribution of relapse phenotypes.

Phylogeny and Classification of Euglenophyceae: A Brief Review

Euglenophyceae (phototrophic euglenids) are an important lineage within the Euglenida, Euglenozoa. Most of the approximately 3,000 described species are free-living, phototrophic, unicellular flagellates with one to several plastids of secondary origin, three bounding membranes and chlorophylls a and b; but, the lineage also includes colorless species that lost their photosynthesizing capability. They show a typical cell membrane consisting of parallel proteinaceous strips and microtubules located underneath the plasma membrane, and discoid mitochondrial cristae. Euglenozoa are a monophyletic group that includes, besides Euglenida, the Kinetoplastidea, Diplonomea and Symbiontida. Since the class Euglenophyceae was proposed, its classification system has undergone several revisions, mainly after the adoption of molecular techniques. This article summarizes recent advances in the phylogeny and classification of the phototrophic euglenids, aiming at understanding the situation of the group within the phylum Euglenozoa, as well as its evolutionary relationships and the changes in its taxonomic classification. The current status of the group, as well as the limitations derived from the lack of inclusion of tropical strains in phylogenetic studies is briefly discussed.

Resistance toFusarium oxysporumf. sp.cubensetropical race 4 in African bananas

Bananas (Musa spp.) constitute one of the most important staple food crops in Africa. Two major groups of bananas exist in Africa: the East African highland banana (EAHB, AAA) in East and Central Africa, and the plantains (AAB) in West Africa. Neither of these groups has been affected by Fusarium oxysporum f. sp. cubense (Foc) race 1, which is the primary fungal pathogen in the continent for banana. The susceptibility of EAHB and plantains to Foc tropical race 4 (TR4) is unknown, and was the focus of this study. A collection of 14 genetically diverse EAHB and plantain cultivars were evaluated in China and The Philippines to determine field resistance to Foc TR4. A field heavily infested with TR4 was used in Guangzhou, China, and another one in Davao City in The Philippines. Disease incidence was determined according to leaf yellowing, pseudostem splitting and confirmed rhizome discoloration. The fungus was also re-isolated from diseased materials and identified by polymerase chain reaction (PCR) using Foc TR4-specific primers. All EAHB and plantain cultivars, except EAHB 'Ibwi', proved to be resistant to the tropical strain of Foc race 4, with disease incidence ranging from 0-5% only. In The Philippines, 'Ibwi' developed Fusarium wilt at an incidence of 32% compared to 46% for 'Williams' and 79% for 'Grand Naine's (both AAA genome, Cavendish subgroup). Similar results were observed in China where most cultivars were severely affected by the corm weevil. Our preliminary results indicate that African bananas are less vulnerable to Foc TR4 compared with some susceptible cultivars in Asia. A more extensive screening of African bananas is required considering the diversity of EAHB and plantains grown in that region.