Transgenic expression of the rice Xa21 pattern‐recognition receptor in banana (Musa sp.) confers resistance to Xanthomonas campestris pv. musacearum

Banana Xanthomonas wilt (BXW), caused by the bacterium Xanthomonas campestris pv. musacearum (Xcm), is the most devastating disease of banana in east and central Africa. The spread of BXW threatens the livelihood of millions of African farmers who depend on banana for food security and income. There are no commercial chemicals, biocontrol agents or resistant cultivars available to control BXW. Here, we take advantage of the robust resistance conferred by the rice pattern‐recognition receptor (PRR), XA21, to the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo). We identified a set of genes required for activation of Xa21‐mediated immunity (rax) that were conserved in both Xoo and Xcm. Based on the conservation, we hypothesized that intergeneric transfer of Xa21 would confer resistance to Xcm. We evaluated 25 transgenic lines of the banana cultivar ‘Gonja manjaya’ (AAB) using a rapid bioassay and 12 transgenic lines in the glasshouse for resistance against Xcm. About 50% of the transgenic lines showed complete resistance to Xcm in both assays. In contrast, all of the nontransgenic control plants showed severe symptoms that progressed to complete wilting. These results indicate that the constitutive expression of the rice Xa21 gene in banana results in enhanced resistance against Xcm. Furthermore, this work demonstrates the feasibility of PRR gene transfer between monocotyledonous species and provides a valuable new tool for controlling the BXW pandemic of banana, a staple food for 100 million people in east Africa.     

pUCPCR1

The mutiple cloning site of pUC19 was replaced by a multiple cloning site possessing a double Xcm1 restriction site. Digestion withXcmI gives a linear vector with a single 3′-overhanging T-residue at both ends. This provides the easiest way of creating a vector in which PCR fragments produced byTaq polymerase can be directly cloned without further modifications.     

Races of Xanthomonas citri subsp. malvacearum,the causal organism of bacterial blight of cotton in northern Nigeria

Xanthomonas citri subsp. malvacearum (Xcm) causes severe qualitative and quantitative losses to farmers in cotton-growing areas of the world. Isolates of Xcm were extracted from cotton seeds obtained from five ginneries located in Funtua, Malumfashi, Gusau and Zaria and standardised to 10^?5?cfu/ml. One isolate per location was used to inoculate three sets of 10 cotton differential lines known to differentiate races of Xcm through possession of B-genes for resistance to bacterial blight. Each cotton differential line was inoculated with the isolates at the six-leaf stage and SDW was inoculated as control. One hundred and sixty pots used were arranged in completely randomised design on the screen house bench. Four different pathogenic races were identified namely race 1, race 12, race 13 and race 16. This confirms the existence of an evolution of the species across northern Nigeria.     

Ecological diversity of edible insects and their potential contribution to household food security in Haut‐Katanga Province,Democratic Republic of Congo

Democratic Republic of the Congo (DR Congo) has a wide diversity of edible insects making it one of the most important biodiversity hot spots in Africa. The aim of this study was to give the first insight into the food plant range, seasonal availability of edible insects, community preference and willingness to consume them. The study revealed a list of eleven edible insect species belonging to four families. Twenty‐six plant species were recorded as food plants of nine edible caterpillar species. Seasonal availability of these insects coincided with the rainy season and was strongly linked to relatively high level of consumption. The caterpillars Elaphrodes lactea Gaede, Lobobunaea saturnus Fabricius and Cinabra hyperbius (Westwood) as well as the termites Macrotermes falciger Gerstäcker were the most dominant species of edible insects preferred and consumed among the different communities. Our study demonstrates that entomophagy is a common practice among the ethnic populations with married, tertiary and university‐level individuals recording significantly higher consumption of edible caterpillars. Populations between the ages of 18 and 45 years as well as the Bemba tribe were also more actively involved in entomophagy. Further research would be necessary to exploit edible insect biodiversity and ethno‐entomophagy and initiate actions for food plant conservation in DR Congo.     

Onion thrips colonization of onion fields bordering crop and non‐crop habitats in muck cropping systems

Onion thrips, Thrips tabaci Lindeman, colonization of onion fields may be influenced by bordering crop and non‐crop habitats. Identifying habitats adjacent to onion fields associated with high T. tabaci infestations would be valuable for improving scouting efforts and management decisions. A 3‐year study examined adult T. tabaci colonization patterns within onion fields early (June through early July) and late in the season (August) in three muck regions in New York (USA). We hypothesized that early‐season adult densities would be greater in onion fields bordering other crops (e.g. carrot, corn and potato) and non‐crops (e.g. woods) than those bordering other onion fields and that more adults would occur along onion field edges than field centres. Results indicated similar adult densities in onion fields regardless of bordering crop and non‐crop habitats in seven of nine muck region × year data sets; exceptions were more adults in onion fields bordering potato (Elba region only) and corn (Potter region only) than those bordering other onion fields. Adult densities decreased as distance into onion fields increased in only four of nine muck region × year data sets; in these cases only 38% more adults were found along field edges than field centres. Later in the season, we hypothesized that adult densities would be greater in non‐mature onion fields bordering mature onion fields, and densities would be greater along field edges than field centres. Results indicated that adult densities in non‐mature onion fields bordering mature onion fields were 54 times greater than those bordering other non‐mature onion fields, and four times more adults occurred along field edges than field centres; adult densities were similar along field edges and centres in non‐mature onion fields bordering other non‐mature onion fields. Implications for T. tabaci management in onion based on these colonization patterns are discussed.     

Highly Efficient Immunodiagnosis of Episomal Banana streak MY virus Using Polyclonal Antibodies Raised Against Recombinant Viral‐Associated Protein

Banana streak MY virus (BSMYV) is the causal agent of viral leaf streak disease of banana, which leads to considerable losses in banana production in most of the banana‐growing regions worldwide. Developing high‐throughput virus detection system is essential for managing viral diseases especially in vegetatively propagated crops like banana. In this study, viral‐associated protein (VAP) coded by ORF II of BSMYV was expressed in Escherichia coli, and polyclonal antibodies were raised against purified recombinant VAP (rVAP) fusion protein in rabbits. Specificity and sensitivity of resulting antibodies were tested in Western blot, immunosorbent electron microscopy (ISEM) and enzyme‐linked immunosorbent assays (ELISAs). In direct antigen‐coated (DAC)‐ELISA, antibodies reacted specifically to BSMYV in crude sap, up to 1 : 8000 dilutions, but not to healthy leaf extracts. Using this antiserum, an immunocapture polymerase chain reaction (IC‐PCR) assay was developed and compared with DAC‐ELISA. VAP antibody‐based IC‐PCR is highly specific and could differentiate episomal virus infection from the integrated endogenous BSV (eBSV) sequences. The recombinant antibodies were validated by testing with a large number of banana germplasm conserved in the field gene bank. Field samples collected during surveys and mother cultures used in tissue culture propagation suggest that antibodies generated against rVAP are sensitive and useful for large‐scale detection of BSMYV. To the best of our knowledge, this is the first report on the production of polyclonal antiserum against recombinant VAP of BSMYV and its suitability for serology‐based testing by ELISA and IC‐PCR. This VAP‐based immunodiagnosis can be applied in quarantine, germplasm exchange and certification programmes.     

A Survey Investigating the Infection of Fusarium langsethiae and Production of HT‐2 and T‐2 Mycotoxins in UK Oat Fields

Fusarium langsethiae is a toxigenic fungal species that has been reported in European small‐grain cereal crops such as oats, wheat and barley. Although its relative contribution to fusarium head blight (FHB) symptoms is not well understood, it is reported to contaminate these cereals with high levels of HT‐2 and T‐2 trichothecenes mycotoxins that are currently under consideration for legislation by the European Commission. Ten commercial oat fields in Shropshire and Staffordshire (two adjacent counties in the Midlands) in the UK were surveyed in the 2006/2007 growing season. Samples were taken from predetermined field locations at Zadoks growth stages 32/33, 69, 77‐85 and 90‐92 for F. langsethiae biomass and HT‐2 and T‐2 toxins quantification. The results from this study showed that oats can be heavily infected with F. langsethiae and have high concentrations of HT‐2 and T‐2 toxins with no apparent FHB symptoms. The regression of HT‐2 + T‐2 toxins on F. langsethiae DNA concentration was highly significant (P < 0.001, r² = 0.55). The results indicated that although F. langsethiae had no direct effect on crop yield, it may result in indirect economic losses where the grain can be rejected or downgraded as a result of intolerable levels of HT‐2 and T‐2 toxins, which are of human food and animal feed safety concern. The influence of cultural field practices on the infection and HT‐2 and T‐2 toxins accumulation in oats was not clear and warrants further studies to identify the sources of F. langsethiae inoculum and conditions favourable for infection and mycotoxin production.     

Seasonal decline of the tomato leafminer,Tuta absoluta,in the shifting landscape of a vegetable‐growing area

Insect pest populations exhibit seasonal dynamics in response to changes in resource availability or other environmental factors such as climatic conditions, natural enemies, and intra‐ or interspecific competition. Understanding such dynamics is critical for developing effective integrated pest management strategies. The objective of the present study was to identify factors driving the seasonal decline of the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in the shifting landscape of a vegetable‐growing area in Senegal. A set of 42 tomato fields was monitored for the number of T. absoluta adults caught in pheromone traps and for the incidence of larvae, during 5 months from June to November 2016 in the Niayes area (Senegal). The surface of solanaceous host crops, climatic conditions, and abundance of natural enemies were also monitored. A drastic decline in T. absoluta abundance was observed during the rainy season. The decrease in resource availability, especially tomato crops, in the surrounding landscape of monitored fields was the main factor affecting the population dynamics during the rainy season. However, alternative host crops such as eggplant and Ethiopian eggplant, can provide ‘reservoirs’ for residual populations of the pest. For applied purpose, it would be interesting to focus the management efforts on residual populations during the rainy season, to make more difficult the reconstitution of populations during the dry season.     

Survival strategies of Dalbulus maidis during maize off‐season in Brazil

Despite the importance of Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) as a vector of maize‐stunting pathogens, it is not understood how this leafhopper survives the maize off‐season in regions where overwintering hosts do not occur. We investigated migration and the use of alternate hosts as possible survival mechanisms for D. maidis during maize off‐season in Brazil. Dalbulus maidis populations were monitored with yellow sticky cards for 16–29 months in Anastácio (Mato Grosso do Sul State), in two farms with perennial pastures (Pasture1 and Pasture2), where maize had not been planted for >5 years, in a subsistence farm >20 km distant, where maize was annually planted (spring) (Maize1), and in Piracicaba (São Paulo State), where maize was grown year round (Maize2). RAPD‐PCR analysis of leafhoppers sampled on maize in two plots (Maize1 and Pasture1) at 15–20 and 110–120 days after germination was performed. Dalbulus maidis was trapped in the maize plots of all areas, but not in weedy or woody vegetation adjacent to the plots. Higher numbers were trapped throughout the year in Piracicaba, where maize was continuously grown under irrigation, and in the subsistence farm of Anastácio, where volunteer maize plants were available for long periods in the maize off‐season. In Anastácio farms, some population peaks were recorded in the absence of maize from midwinter to early spring, especially after soil plowing. RAPD‐PCR analysis showed that D. maidis populations sampled were genetically similar. Our data suggest that D. maidis uses a mixed strategy to survive the over‐season period in Brazil, in which part of the population overwinters locally on volunteer maize plants or nearby irrigated maize crops, whereas the other individuals migrate to colonize new maize crops in distant areas or regions. We hypothesize that immigrant D. maidis uses the contrast between plowed and vegetated soil as a visual cue for locating new maize crops.     

A 13‐lipoxygenase is Expressed Early in the Hypersensitive Reaction of Cotton Plants to Xanthomonas campestris pv. malvacearum

Lipoxygenases (LOXs) are enzymes responsible for lipid peroxidation processes during plant defence responses to pathogen infection. Jasmonates are lipid‐derived signals that mediate plant stress responses with chloroplastic LOXs implicated in the biosynthesis of oxylipins like jasmonic acid (JA). Hypersensitive reaction (HR) cell death of cotton to the incompatible race 18 of Xanthomonas campestris pathovar malvacearum (Xcm) is associated with 9S‐lipoxygenase activity and expression of a 9‐LOX GhLOX1. Here, we report the cloning of cotton (Gossypium hirsutum L.) LOX gene GhLOX2. Sequence analysis showed that GhLOX2 is a putative 13‐LOX with a chloroplast‐transit peptide in the amino acid terminus. GhLOX2 was found to be significantly expressed in the first hour of Xcm‐induced HR. Investigation into LOX signalization on cotyledons incubated with methyl‐jasmonate (MeJA) or infiltrated with salicylic acid (SA) or ethylene (ET) revealed that the first two treatments induced GhLOX2 gene expression. Our results show that GhLOX2 gene expression occurred at the stage of the HR prior biochemical events previously highlighted. The role that GhLOX2 may have in the defence strategy of cotton to Xcm is discussed regarding the HR.     

Biomechanical properties of the emergent aquatic macrophyte Sparganium erectum: Implications for fine sediment retention in low energy rivers

This paper is concerned with the biomechanical properties of the emergent aquatic macrophyte, Sparganium erectum. We present observations of adjustments in the physical characteristics and biomechanical properties of S. erectum during the growing season (April-November) from the River Blackwater, UK. When a pulling device is attached to plant stems to measure their resistance to uprooting, individual plants show remarkable strength in their above- and below-ground biomass (median stem strength when stems break away from the underground biomass, 78 N, median rhizome strength, 39 N) and high resistance to uprooting (median uprooting resistance when entire plants uproot, 114 N). This provides the potential for the species to protect and reinforce the generally soft, silty sediments that it often retains and within which its rhizomes and roots develop in lower energy river environments. There is a propensity for plant stems to break before the plant is uprooted at the beginning and end of the growth season, but for the stems to have sufficient strength in mid season for plant uprooting to dominate. This ensures that rhizome and root systems remain relatively undisturbed at times when the silty sediments in which they grow are poorly protected by above-ground biomass. In contrast, rhizome strength remains comparatively invariant through the growing season, supporting the plant's potential to have a protective/reinforcing effect on fine sediments through the winter when above ground biomass is absent.     

When beggars are choosers—How nesting of a solitary bee is affected by temporal dynamics of pollen plants in the landscape

Wild bees are declining in intensively farmed regions worldwide, threatening pollination services to flowering crops and wild plants. To halt bee declines, it is essential that conservation actions are based on a mechanistic understanding of how bee species utilize landscapes. We aimed at teasing apart how foraging resources in the landscape through the nesting season affected nesting and reproduction of a solitary bee in a farmland region. We investigated how availability of floral resources and potentially resource‐rich habitats surrounding nests affected nest provisioning and reproduction in the solitary polylectic bee Osmia bicornis. The study was performed in 18 landscape sectors dominated by agriculture, but varying in agricultural intensity in terms of proportion of organic crop fields and seminatural permanent pastures. Pasture‐rich sectors contained more oak (Quercus robur), which pollen analysis showed to be favored forage in early season. More oaks ≤100 m from nests led to higher proportions of oak pollen in nest provisions and increased speed of nest construction in early season, but this effect tapered off as flowering decreased. Late‐season pollen foraging was dominated by buttercup (Ranunculus spp.), common in various noncrop habitats. Foraging trips were longer with more oaks and increased further through the season. The opposite was found for buttercup. Oak and buttercup interacted to explain the number of offspring; buttercup had a positive effect only when the number of oaks was above the mean for the studied sectors. The results show that quality of complex and pasture‐rich landscapes for O. bicornis depends on preserving existing and generating new oak trees. Lignose plants are key early‐season forage resources in agricultural landscapes. Increasing habitat heterogeneity with trees and shrubs and promoting suitable late‐flowering forbs can benefit O. bicornis and other wild bees active in spring and early summer, something which existing agri‐environment schemes seldom target.     

香蕉园黄胸蓟马成虫种群的活动节律、消长规律与空间分布

为系统明确黄胸蓟马在香蕉园的活动节律、消长规律与空间分布。采用蓝色诱虫板诱集法和田间踏查法,在2016—2018年期间调查了香蕉园黄胸蓟马成虫的活动高度情况、日间节律、以及不同香蕉品种(南天黄、巴西蕉与皇帝蕉)与不同地区(海南澄迈、广西玉林与云南景洪)的种群消长规律,同时分析了其空间分布格局与性比。结果显示:高度与蓟马种群数量密切相关,2—6 m是香蕉园黄胸蓟马的主要活动高度范围;蓟马种群的活动节律在晴、阴与雨天基本一致,日活动高峰时段为12:00—16:00时,夜间和阴雨天均活动少;黄胸蓟马的种群动态不受香蕉作物品种和地理区域的影响,但与香蕉作物的生长期密切相关;年度消长规律呈现单峰型,香蕉进入花蕾期时,蓟马种群数量快速增长,盛花期时达到高峰,其余时期少有发生。聚集指标与Taylor回归法分析共同表明黄胸蓟马成虫在香蕉园的空间分布型为聚集式分布。性比调查发现黄胸蓟马在香蕉花蕾内的雌虫比例约为70%,表明该虫是一个雌性为主的种群。为揭示黄胸蓟马的灾变规律提供了基础数据,同时可为香蕉蓟马的适时与精准化监测预报及防治提供指导依据。     

Fusarium Species Isolated from Common Weeds in Eggplant Fields and Symptomless Hosts of Fusarium oxysporum f. sp. melongenae in Turkey

Thirteen species of weed plants were collected between May and September in 2010 and 2011 from eggplant fields representing 11 distinct locations covering a wide geographical area of Turkey. Weeds are potential hosts of many plant pathogens and may not exhibit disease symptoms when colonized. Fusarium spp. were isolated from five monocotyledonous species and eight dicotyledonous species. A total of 212 isolates recovered from weeds were assigned to eight Fusarium species on the basis of morphological characteristics. F. oxysporum was the most frequently isolated species (29.7%), followed by F. solani (19.8%), F. graminearum (13.7%), F. verticillioides (12.7%), F.equiseti (9.9%), F. avenacearum (8.0%), F. proliferatum (3.8%) and F. subglutinans (2.4%). The F. oxysporum isolates from different weed hosts were characterized by means of pathogenicity and vegetative compatibility grouping (VCG) tests. Among these, 29 isolates were found to be pathogenic to eggplant cv. Kemer and re‐isolated as Fusarium oxysporum Schlecht. f. sp. melongenae (Fomg) as evidenced. These isolates from weed hosts were assigned to VCG 0320. This study is the first report of Fomg isolated from weeds in eggplant fields in Turkey. None of the weed species tested showed symptoms of wilting in pot experiments, and F. oxysporum was isolated with greater frequency from all inoculated weeds. The results of this study indicate that several weed plants may serve as alternative sources of inoculum for Fomg, during the growing season.     

Colonization preference of Euschistus servus and Nezara viridula in transgenic cotton varieties,peanut, and soybean

Producers of Bt cotton, Gossypium hirsutum L. (Malvaceae), in the southeastern USA face significant losses from highly polyphagous stink bug species. These problems may be exacerbated by crop rotation practices that often result in cotton, peanut, Arachis hypogaea L., and soybean, Glycine max (L.) Merrill (both Fabaceae), growing in close proximity to one another. Because all of these crops are hosts for the major pest stink bug species in the region, we experimentally examined colonization preference of these species among the crops to clarify this aspect of their population dynamics. We planted peanut, soybean, Bt cotton, and glyphosate‐tolerant (RR) non‐Bt cotton at three sites over 3 years in replicated plots ranging from 192 to 1 323 m² and calculated odds ratios for colonization of each crop for Nezara viridula (L.) and Euschistus servus (Say) (both Hemiptera: Pentatomidae). In four of five experiments, both E. servus and N. viridula preferred soybean significantly more often than Bt cotton, non‐Bt cotton, and peanut. Neither N. viridula nor E. servus showed any preference between non‐Bt and Bt cotton in any experiment. Both species had higher numbers in Bt and non‐Bt cotton relative to peanut; this was not significant for any single experiment, but analyses across all experiments indicated that N. viridula preferred Bt and non‐Bt cotton significantly more often than peanut. Our results suggest that soybean in the landscape may function as a sink for stink bug populations relative to nearby peanut and cotton when the soybean is in the reproductive stage of development. Stink bug preference for soybean may reduce pest pressure in near‐by crops, but population increases in soybean could lead to this crop functioning as a source for later‐season pest pressure in cotton.     

Detection of Ralstonia solanacearum in Soil and Weeds from Commercial Tomato Fields Using Immunocapture and the Polymerase Chain Reaction

A detection assay for Ralstonia solanacearum in soil and weeds was developed by combining immunocapture and the polymerase chain reaction (IC‐PCR). Anti‐R. solanacearum polyclonal antibodies were produced in a white female rabbit and Dynal^® super‐paramagnetic beads were coated with purified immunoglobulinG (IgG). Using IC‐PCR, the 718 bp target DNA was amplified at a detection threshold of approximately 10⁴ colony‐forming units (CFU) bacteria per millilitre of suspension. DNA was not amplified in soil suspensions derived from autoclaved and non‐autoclaved soils, which contained R. solanacearum at 1–10⁵ CFU/g soil. However, a positive PCR result was obtained when bacteria in the soil suspensions were first enriched in nutrient broth. IC‐PCR detected R. solanacearum in tomato stems 24 h after inoculation by stem puncture with a suspension containing approximately 10⁵ CFU/ml. IC‐PCR detected the bacterium in 28 of 55 (51%) weeds and 10 of 32 (31%) soil samples. Of the weeds, Physalis minima, Amaranthus spinosus and Euphorbia hirta had the highest incidence of infection. R. solanacearum was not detected in soil taken from fallow fields, but it was discovered in some weed species. Symptomless tomato and pepper plants collected from the fields in which tomato bacterial wilt had previously occurred were found to contain R. solanacearum. These discoveries suggest that weeds and latent hosts may play a role in the survival of R. solanacearum between cropping cycles.     

Quantification of Monosporascuscannonballus Ascospores in Muskmelon Fields in Eastern Spain

The populations of Monosporascuscannonballus ascospores in the soils of 14 muskmelon fields throughout muskmelon production areas of Comunidad Valenciana (eastern Spain) were quantified from 2002 to 2003. The fields were surveyed in July, at the end of the cropping season, when plants approached maturity and symptoms of vine decline in the canopy appeared as patches of wilted or dead plants. Ascospores were recovered from all muskmelon fields surveyed. The average soil populations ranged from 1.54 to 6.33 per g of soil and the number of ascospores within a soil sample ranged from 0.50 to 16.20 ascospores/g of soil. This is the first detailed report on ascospore populations of M. cannonballus in muskmelon fields from a cucurbit‐growing area in Spain and the Mediterranean basin.     

The impact of plant associations on Macrosteles quadrilineatus management in carrots

Habitat diversification can influence the interactions of insects with plants and this can be used in agroecosystems for the management of pest populations. Plant diversification can be achieved through planting crops, such as trap crops, or by adjusting weed management. Aster leafhopper, Macrosteles quadrilineatus Forbes (Hemiptera: Cicadellidae), is a polyphagous species that uses cereals, vegetables, and weeds as host plants. The influence of weeds on M. quadrilineatus abundance was investigated experimentally in carrot [Daucus carota L. cv. Canada (Apiaceae)] field plots by adjusting the level of management of two groups of weeds (broadleaf and grass) and by comparing it to weed‐free plots. The preference of M. quadrilineatus for different cereal and weed species relative to carrots was tested in choice test assays. Habitat context influenced the abundance of M. quadrilineatus in the field experiments. The presence of border crops such as oat, rye, barley, wheat, and triticale did not significantly attract or repel this insect to carrot plots compared to the no‐border treatment. However, spelt‐bordered plots had 42% fewer M. quadrilineatus than three treatments, triticale, wheat, and barley, that had the highest insect abundance. The type of weed management affected M. quadrilineatus abundance in carrot plots, but not the frequency of herbicide application. Plots that had carrot growing with broadleaf‐weeds had about 59% fewer M. quadrilineatus compared with those growing with crabgrass or carrot alone. In the greenhouse choice tests, grasses (e.g., cereals) attracted and broadleaf‐weeds repelled M. quadrilineatus relative to carrots. In summary, carrot growers may be able to manage this pest by reducing the interaction of cereal cover crops with carrots and eliminating grassy weeds in commercial production fields.     

Golden bananas in the field: elevated fruit pro‐vitamin A from the expression of a single banana transgene

Vitamin A deficiency remains one of the world's major public health problems despite food fortification and supplements strategies. Biofortification of staple crops with enhanced levels of pro‐vitamin A (PVA) offers a sustainable alternative strategy to both food fortification and supplementation. As a proof of concept, PVA‐biofortified transgenic Cavendish bananas were generated and field trialed in Australia with the aim of achieving a target level of 20 μg/g of dry weight (dw) β‐carotene equivalent (β‐CE) in the fruit. Expression of a Fe'i banana‐derived phytoene synthase 2a (MtPsy2a) gene resulted in the generation of lines with PVA levels exceeding the target level with one line reaching 55 μg/g dw β‐CE . Expression of the maize phytoene synthase 1 (ZmPsy1) gene, used to develop ‘Golden Rice 2’, also resulted in increased fruit PVA levels although many lines displayed undesirable phenotypes. Constitutive expression of either transgene with the maize polyubiquitin promoter increased PVA accumulation from the earliest stage of fruit development. In contrast, PVA accumulation was restricted to the late stages of fruit development when either the banana 1‐aminocyclopropane‐1‐carboxylate oxidase or the expansin 1 promoters were used to drive the same transgenes. Wild‐type plants with the longest fruit development time had also the highest fruit PVA concentrations. The results from this study suggest that early activation of the rate‐limiting enzyme in the carotenoid biosynthetic pathway and extended fruit maturation time are essential factors to achieve optimal PVA concentrations in banana fruit.